ASHS 2024 Conference: Full Schedule

9:59am HST

Growth Chambers and Controlled Environments 1 (CE 1)

Tuesday September 24, 2024 9:59am - 12:00pm HST

Transcriptomic Analysis of Kale (Brassica oleracea) Grown Under Different Light Emitting Diode Wavelengths Revealed Potential Genes Responsible for Phenotypic Changes - Tristan Sanders
Blue Light Mediates Far-Red Light Effects on Increasing Leaf Area and Shoot Mass of Kale and Lettuce - Jiyong Shin
Interactions Between Blue Light and Far-Red Light on Growth of Culinary Herbs - Bridget Knight
Blue and Green Light and Temperature Interactively Regulate Growth, Morphology, Physiology, and Phytochemicals of Lettuce - Sangjun Jeong
Switching From Low to High Blue Light Before Harvest Increases Nutritional Quality While Maintaining High Biomass in Red-leaf Lettuce Under Elevated CO2 - Shem Msabila
Supplemental Blue and UV-B Light Enhances Amino Acid-Derived Flavor Compounds in Greenhouse-Grown Tomatoes - Samikshya Bhattarai
Characterizing the effect of blue light on water relations of unrooted cuttings during indoor acclimation - Ana Sofia Gomez
Shedding Light on Nutrition: The Influence of Supplemental Lighting on Glucosinolate Concentrations in Brassica Plants and Their Potential Anticarcinogenic Effects in Human Diets - Skyler Brazel

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Tuesday September 24, 2024 9:59am - 12:00pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:00am HST

CE 1 - Transcriptomic Analysis of Kale (Brassica oleracea) Grown Under Different Light Emitting Diode Wavelengths Revealed Potential Genes Responsible for Phenotypic Changes

Tuesday September 24, 2024 10:00am - 10:15am HST

Coral 1

Light emitting diodes (LEDs) of different wavelengths significantly influenced kale growth, morphology, and nutrient content. The importance of indoor agriculture is being recognized, but few studies have investigated the influence of LEDs, particularly green wavelengths, on crops at the transcriptome level. The objective of this study was to use RNA sequencing technology to elucidate the genetic response of kale to blue (BV), green (G), and red (RF) LEDs compared to the combination of all the LEDs (RFBVG), control. Results revealed total amount of differentially expressed genes (DEGs) was 1373 for kale grown under BV LEDs, 924 under G LED, and 133 under the RF LED treatments. DEGs enriched in kale grown under RF LEDs played roles in regulating hormone metabolic processes and oxidoreductase activity. In the BV treatment, several enzymes in the phenolic biosynthetic pathway were upregulated compared to the control which may explain previous results reporting higher levels of phenolic content in kale grown under BV LEDs. In the G LED treatment, the expression of genes related to photosynthesis, heme binding, and oxidoreductase activity were upregulated compared to those in the control group. These results may support previous findings of higher iron content in kale grown under G LEDs. Further, the G LED treatment upregulated the expression of cytochrome P450 enzymes, which play key roles in plant growth and stress responses. Understanding the molecular mechanisms underlying the effects of different LED wavelengths by RNAseq provides information to improve indoor cultivation practices that optimize crop growth and nutrient value.

Speakers

Tristan Sanders

West Virginia University

Co-authors

Janet Tou

West Virginia University

Nicole Waterland

West Virginia University

Youyoun Moon

West Virginia University

Tuesday September 24, 2024 10:00am - 10:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:15am HST

CE 1 - Blue Light Mediates Far-Red Light Effects on Increasing Leaf Area and Shoot Mass of Kale and Lettuce

Tuesday September 24, 2024 10:15am - 10:30am HST

Coral 1

There are contrasting effects of far-red (FR; 700–750 nm) light on leaf area and biomass in plants. These differences have been attributed to photon flux density (PFD) and species/cultivar differences. In a previous experiment, total PFD (TPFD) did not mediate the influence of FR light on leaf area and shoot mass when the TPFD alterations were only of red (R; 600–699 nm) and FR light. Therefore, we hypothesized that blue (B; 400–499 nm) light controls the influence of TPFD in regulating the effects of FR light on leaf area and shoot mass. We cultivated kale (Brassica oleracea var. sabellica) ‘White Russian’ and lettuce (Lactuca sativa) ‘Rex’ and ‘Rouxai’ under 12 lighting treatments with a 24 h∙d−1 photoperiod and TPFDs of 85, 170, 255, or 340 µmol∙m−2∙s−1 and FR fractions [FR-PFD divided by the sum of R and FR PFD] of 0.00, 0.17, or 0.33. The alterations in the TPFDs were solely due to B-PFD; the sum of R and FR PFD was constant in all treatments. Preliminary results indicate that elevated FR fraction did not increase leaf area and shoot mass of all three crops in the absence of B light, when the TPFD was 85 µmol∙m−2∙s−1. However, a high B-PFD and thus TPFD amplified the effects of a high FR fraction at increasing leaf area and shoot mass of all three cultivars. These high FR-fraction effects were correlated with increased biomass partitioning to leaves at a high B-PFD and thus TPFD. These results imply that the contrasting effects of FR light on leaf area and biomass in previous studies could be attributed to the B-PFD. In addition, the influence of TPFD on FR-fraction effects is primarily influenced by the B-PFD.

Speakers

Jiyong Shin

Michigan State University

Co-authors

Erik Runkle

Michigan State University

Tuesday September 24, 2024 10:15am - 10:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:30am HST

CE 1 - Interactions Between Blue Light and Far-Red Light on Growth of Culinary Herbs

Tuesday September 24, 2024 10:30am - 10:45am HST

Coral 1

Light quality can regulate growth and quality characteristics of young plants, but responses of culinary herb transplants are not well understood. Blue light generally inhibits extension growth while far-red light promotes stem elongation and leaf expansion. The objective of this study was to investigate the interaction between blue (400-499 nm) and far-red (700-750 nm) light on six culinary herb species, basil ‘Nufar’, cilantro ‘Santo’, parsley ‘Giant of Italy’, sage ‘Extraka’, mint ‘Spearmint’, and oregano ‘Greek’, with the goal of producing high-quality transplants with compact growth. Six indoor lighting treatments were tested with blue light photon flux densities (PFDs) of 20, 60, or 100 µmol∙m−2∙s−1 and far-red light of 0 or 60 µmol∙m−2∙s−1, with red light (600-699 nm) added so that the total PFD was 210 µmol∙m−2∙s−1 in all treatments. Seeds were sown in 72-cell trays at a constant 23 °C under a 16-h photoperiod and grown for 28-44 days until harvest. As expected, treatments with the highest far-red and lowest blue light PFDs had the greatest extension growth and those with no far-red and high blue light were the most compact. Preliminary results indicate basil, cilantro, and mint exhibited the greatest leaf area under high blue and far-red light. Generally, all species had the highest shoot fresh mass when grown with far-red light. We conclude that blue light and far-red light interact to regulate plant height and leaf area, especially in basil and sage. Therefore, including blue and far-red in the light spectrum should be considered to manage the morphology of young culinary herb plants.

Speakers

Bridget Knight

Michigan State University

Co-authors

Erik Runkle

Michigan State University

Tuesday September 24, 2024 10:30am - 10:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:45am HST

CE 1 - Blue and Green Light and Temperature Interactively Regulate Growth, Morphology, Physiology, and Phytochemicals of Lettuce

Tuesday September 24, 2024 10:45am - 11:00am HST

Coral 1

Substituting green (G; 500-600 nm) for blue (B; 400-500 nm) light can enhance crop yield through increasing leaf expansion and photon capture in indoor farming. In addition to yield, the concentration of phytochemicals may also be influenced by varying B to G light ratios. Those responses to B and G light are primarily mediated by cryptochrome photoreceptors. However, cryptochrome activity is further dependent on temperature. We hypothesized that B and G light and temperature could interactively regulate plant morphology, physiology, and secondary metabolites, consequently impacting crop yield and nutritional quality. Two cultivars of lettuce (Lactuca sativa L.), ‘Rouxai’ and ‘Rex’, were grown under three temperatures (20, 24, and 28 ℃) and five spectral treatments composed of B, G, and red (R; 600-700 nm) light (B40G0R60, B30G10R60, B20G20R60, B10G30R60, and B0G40R60). The subscript number following each light type represents its percentage in total photon flux density (TPFD; 400-800 nm). TPFD was maintained at a constant level of 200 μmol·m-2·s-1, with R photon flux of 120 μmol·m-2·s-1 (60% of TPFD) in all treatments. Results revealed that light spectra and temperature interactively influenced plant morphology. Specifically, in Rouxai, increasing G light from 0% to 40%, coupled with decreasing B from 40% to 0%, linearly increased total leaf area at all three temperatures. Notably, the substitution of G for B light caused the greatest leaf expansion at 24 ℃ (a 64% increase at 20 ℃, a 90% increase at 24 ℃, and a 32% increase at 28 ℃). In Rex, substituting G light for B light up to 30% increased total leaf area at 20 and 24 ℃, but not at 28 ℃. Similar to Rouxai, the spectral effect on the leaf expansion of Rex was greater at 24 ℃, compared to 20 ℃. Shoot dry weight responded to spectral and temperature treatments similarly as total leaf area. Secondary metabolites (e.g., phenolics and flavonoids) and antioxidant capacity consistently decreased with increasing G light (or decreasing B from 40% to 0%), but the decline was more pronounced at warmer temperatures. Without significant interaction between light spectrum and temperature, chlorophyll and carotenoid contents decreased with increasing G light. Thus, we concluded that the proportion of B and G light and temperature interactively regulated plant morphology and secondary metabolites, ultimately affecting crop yield and nutritional quality. Our study emphasizes the importance of considering the interaction between light spectrum and temperature in optimizing production systems.

Speakers

Sangjun Jeong

Texas A

Co-authors

Genhua Niu

Texas A

Shuyang Zhen

Tuesday September 24, 2024 10:45am - 11:00am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:00am HST

CE 1 - Switching From Low to High Blue Light Before Harvest Increases Nutritional Quality While Maintaining High Biomass in Red-leaf Lettuce Under Elevated CO2

Tuesday September 24, 2024 11:00am - 11:15am HST

Coral 1

Growing food crops in space supports astronauts’ dietary needs in long-duration space missions and necessitates efficient use of light. In red-leaf lettuce (Lactuca sativa), sufficient red (R) and far-red (FR) light promote extension growth, whereas sufficient blue (B) light restricts extension growth but enhances secondary metabolite accumulation. Green (G) light also contributes to photosynthesis and improves visual quality. Compared to fixed light spectra, we evaluated dynamic light spectra to balance harvestable biomass and nutritional quality of red-leaf lettuce ‘Outredgeous’ under elevated CO2 concentration (≈2794 μmol⋅mol–1) and intermediate relative humidity (≈48%), typical on the International Space Station. This ground-based growth chamber experiment was performed twice following a randomized complete block design. We grew plants hydroponically at ≈22 °C under light-emitting diodes (LEDs) with four fixed light spectra and four dynamic light-spectrum alternations. The four fixed light spectra from seed to harvest were B60R140, B10R190, B10G50R140, and B10R140FR50 (the subscript following each waveband denotes its photon flux density in μmol·m−2·s−1). The four dynamic light-spectrum alternations switched among B10R190, B10G50R140, and B10R140FR50 in the lag (day 0–11) and exponential growth (day 11–25) phases, followed by B60R140 in the finish phase (day 25–28). Plant data were collected 11 and 28 days after sowing for seedlings and mature plants, respectively. Among the fixed light spectra, increasing the B photon flux density decreased shoot mass by 28% to 39% but increased total phenolic concentration by 27% to 45% in mature plants. Partial substitution of R light with G light decreased shoot mass by 31% to 42% in seedlings, but not mature plants. Partial substitution of R light with FR light did not influence shoot mass of seedlings or mature plants. Compared with fixed low B light treatments, dynamic light-spectrum alternations with high B light in the finish phase did not affect shoot mass, root mass, or leaf number while increasing total phenolic concentration by 8% to 25%. In addition, partial substitution of R light with G or FR light during the lag or exponential growth phase did not influence shoot or root mass. We conclude that low B light in the lag and exponential growth phases followed by short-term high B light in the finish phase improves lettuce nutritional quality without decreasing biomass as seen under long-term high B light. Spectrum selection in the earlier phases should prioritize the photosynthetic photon efficacy of LEDs to maximize light use efficiency.

Speakers

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

Tuesday September 24, 2024 11:00am - 11:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:15am HST

CE 1 - Supplemental Blue and UV-B Light Enhances Amino Acid-Derived Flavor Compounds in Greenhouse-Grown Tomatoes

Tuesday September 24, 2024 11:15am - 11:30am HST

Coral 1

Tomato production under controlled environmental conditions presents challenges due to the selective permeation of solar radiation within enclosed structures or the limited wavelengths produced by artificial light sources. Despite these challenges, growers increasingly opt for such production systems due to the enhanced uniformity and yield of fruit compared to open-field cultivation. However, controlled environment conditions, particularly greenhouses, often limit specific wavelengths of light, including blue and UV-B radiation. This limitation has the potential to alter flavor and overall fruit quality. Therefore, the present investigation examined how supplemental blue and UV-B light, independently and in combination, influence the levels of amino acid–derived flavor compounds, particularly those derived from branched-chain and aromatic amino acids, in two tomato varieties, Plum Regal (PR, commercial) and TAM HOT-Ty (THT, Texas A

Speakers

Samikshya Bhattarai

Graduate Research Assistant, Texas A&M University

Co-authors

Bhimanagouda Patil

Texas A

Deepak Jha

Texas A

Shuyang Zhen

Tuesday September 24, 2024 11:15am - 11:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:30am HST

CE 1 - Characterizing the effect of blue light on water relations of unrooted cuttings during indoor acclimation

Tuesday September 24, 2024 11:30am - 11:45am HST

Coral 1

Managing water loss of unrooted cuttings (URC) during acclimation is critical to decrease crop losses and shorten rooting time. Vertical indoor propagation (VIP) systems that use indoor-farming technologies enable the opportunity to optimize the environment for URC acclimation. However, recommend environmental setpoints for VIP systems are unknown. Light quality affects various morphological and physiological processes in plants, and blue light in particular, has an effect on stomatal opening and plant size, both of which regulate water relations of plants. Therefore, the objective of this study was to characterize short-term effects of increasing percentages of blue light on water relations of Chrysanthemum ‘Crystal Bright’ and Begonia ‘Dark Britt’ URC. Four light-quality treatments were evaluated: 15%, 30%, 45%, or 60% blue light. All treatments provided a photosynthetic photon flux density of 70 µmol·m–2·s–1 delivered by broadband and monochromatic-blue light-emitting diode fixtures. Ambient temperature, relative humidity, and carbon dioxide concentration were set at 22 °C, 70%, and 420 μmol·mol–1. Water uptake and water loss were evaluated by placing individual URC in vials with and without water, and exposing them to each treatment for 24 or 48 h, respectively. Changes in water loss were also recorded at various intervals for 24 h. Water uptake of Chrysanthemum linearly increased as blue-light percentages increased. In contrast, water uptake followed a quadratic response for Begonia, which peaked at 45% blue light. Water loss also followed a quadratic response for begonia, with increasing values up to 30% blue light. Water loss of Chrysanthemum followed linear response to increasing blue light. After 24 h, water loss of Chrysanthemum linearly increased with increasing blue light, from 0.65 to 0.76 g under 15% and 60% blue light, respectivey. There were no treatment differences for stomatal conductance, but leaf vapor pressure deficit linearly increased with increasing blue light, regardless of species. These findings show that blue light affects water relations of URC, which should be considered when making lighting recommendations for VIP systems.

Speakers

Ana Sofia Gomez

Purdue University

Co-authors

Celina Gomez

Purdue University

Tuesday September 24, 2024 11:30am - 11:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:45am HST

CE 1 - Shedding Light on Nutrition: The Influence of Supplemental Lighting on Glucosinolate Concentrations in Brassica Plants and Their Potential Anticarcinogenic Effects in Human Diets

Tuesday September 24, 2024 11:45am - 12:00pm HST

Coral 1

Brassica plants contain important secondary metabolites, such as glucosinolates, and provide a nutritious addition to the human diet. Glucosinolates, when hydrolyzed, yield isothiocyanates which can affect the carcinogenesis process, and further research into increasing glucosinolate concentrations in plants is important for determining anticarcinogenic properties of brassicas in human diets. Kale (Brassica oleracea var. acephala cv. ‘Toscano’ ) and Arabidopsis (Arabidopsis thaliana, Col-0) were grown in the greenhouse under natural light (control) and subjected to three additional supplemental light treatments to determine the impact of supplemental LED lighting on glucosinolate concentrations. Treatments included no supplemental light (control), 75:25 Red:Blue LED, 50:50 Red:Blue LED, and Warm White LED light at 100 μmol.m-2.s-1 each. Plants were harvested when the first kale treatment group reached a leaf number of 7, and when half of all Arabidopsis flowers began opening. Harvested plants were analyzed for glucosinolate and mineral nutrient concentration. Statistical analysis on Arabidopsis data revealed significant differences among light treatments in glucosinolate concentrations, particularly glucoraphanin and gluconasturtiin. Additionally, significant differences were found in leaf and petiole mass and leaf number of both kale and Arabidopsis at harvest. The no supplemental light control produced the lowest harvest mass compared to plants receiving supplemental light. Preliminary qPCR analysis of Arabidopsis displays variations in the relative expression of genes CYP79B2 and CYP83A1, varying across treatment when compared to the control. Glucosinolate analysis of kale resulted in no statistically significant differences among all four light treatments. However, glucosinolates, including gluconapin, glucoraphanin, gluconasturtiin, and several unknowns, were found to be present across all four treatments. As glucosinolates are stress-response compounds, their lack of variation in kale and significant variation in Arabidopsis under different light environments indicate that other environmental factors also play a crucial role in their production. Further research is necessary to identify abiotic and biotic factors influencing their concentration in the greenhouse environment for both species.

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Caleb Zepeda

University of Tennessee - Knoxville

Carl Sams

University of Tennessee

Samantha Nuzzi

Donald Danforth Plant Science Center

Tessa Burch-Smith

Donald Danforth Plant Science Center

Tuesday September 24, 2024 11:45am - 12:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

1:00pm HST

Plant Nutrient Management Interest Group Meeting

Tuesday September 24, 2024 1:00pm - 2:00pm HST

Sea Pearl 4

Plant Nutrient Management Interest Group
The purpose of this meeting is to align the ASHS mission to develop nutrient management strategies for horticultural field and controlled environment-grown plants, (1) to maximize plant productivity, and (2) to reduce environmental footprints by restricting nutrient loss where it can impact greenhouse gas emissions and water quality.

Moderator

Vijay Joshi

Texas A

Tuesday September 24, 2024 1:00pm - 2:00pm HST
Sea Pearl 4

Meetings - Committee/Division/interest Group

SUBJECT Growth Chambers and CE, Plant Nutrient Mgmt

4:00pm HST

AI Innovation for Horticulture - Part 1

Tuesday September 24, 2024 4:00pm - 6:00pm HST

Coral 3

Sponsoring Professional Interest Groups
Technology: Coordinator Milt McGiffen - milt.mcgiffen@ucr.edu
Teaching Methods: Coordinator, Kathryn Orvis – orvis@purdue.edu
Controlled Environment: Coordinator, Kent Kobayashi - kentko@hawaii.edu

Supporting Professional Interest Groups
Federal Partners: Matthew Mattia - Matthew.Mattia@usda.gov
Plant Biotech: Kedong Da - kda@ncsu.edu
Ornamentals/Landscape and Turf; Youping Sun - youping.sun@usu.edu
Local Food Systems: Charles H. Parrish II - chip.parrish@pm.me

Artificial intelligence and related topics, e.g., robotics, have been a long time coming in
agriculture. For decades there have been predictions of intelligent robots replacing
humans, and large farms run by a few humans with many autonomous tractors and
other devices. But with the now widespread use of artificial intelligence in everyday life,
the moment has arrived. We developed this colloquium by casting a wide net out to all
the Professional Interest Group Chairs, and have assembled talks and demonstrations
from general topics to specific applications.

Two online meetings were held, where Professional Interest Groups officers and those interested suggested
speakers and discussed topics. Further discussions over email helped fill in the details
to create this colloquium.

We will have a block of speakers for the diverse topics we present below, as well
as panel discussions on how AI is and can be incorporated into various aspects of
Horticulture, so that there is ample time for questions and discussion.

Title: Overview of the Colloquium

Speaker: Milt McGiffen, Cooperative Extension Specialist, Department of Botany and Plant Sciences,
University of California, Riverside, CA.

AI in Ornamentals

Title: FloraScore: An App for Rapid Assessment of Pollinator Attractiveness to Annuals
and Perennial Plants.

Description: Customers are interested in buying annuals and perennials that support
pollinators. Protocols for rapid assessment in flower trail evaluations are not
available. We have developed a mobile app that can be used to analyze in real time the
users’ observational data and quantitatively rank the relative utility of observed cultivars
to pollinator communities. This app takes into account pollinator groups, relevant floral
characteristics and landscape.

Presenter: Harland Patch
Assistant Research Professor
Department of Entomology
Penn State University
549 Ag Sciences & Industries Building
University Park, PA 16802

Title: Approach to Biodiversity Protection: Employing AI and IoT Systems for the
Containment of Box Tree Moth Proliferation.

Description: The box tree moth (BTM, Cydalima perspectalis) is an invasive pest first
confirmed in Niagara County, New York in 2021. This invasive pest can significantly
damage and potentially kill boxwood (Buxus species) plants if left unchecked. This
presentation describes our advances in combining deep learning algorithms for
enhanced computer vision with IoT-enabled smart traps, to facilitate the early detection
and continuous monitoring of BTM populations and to protect the prevalent ornamental
boxwood in U.S. landscapes.

Presenter: Yanqiu Yang (she/her)
Ph.D. Graduate Research Assistant
Department of Agricultural and Biological Engineering
Pennsylvania State University
3 Agricultural Engineering Building
University Park, PA 16802

Title: Landscapes from Words: The Future of Landscape Design with AI.

Description: The ongoing text-to-graphic artificial intelligence (AI) revolution has the
potential to change the field of Landscape Architecture dramatically. The ability to
produce original high-quality graphics, manipulate the viewer's perspective of images,
and amend the rendering style through text inputs are significant advancements that will
inform new design process models. These changes can lead to expanded design
exploration, improved accessibility for non-designers to contribute to creating visual
concepts, enhanced ability to integrate data analysis and visualizations, and
streamlined collaboration between clients and project stakeholders using a shared
visual language. This talk focuses on two dimensions of change that may result from the
rapid evolution of text-to-graphic AI, including (1) faster iterations and exploration of
design options and (2) the advancement of methods that result in more inclusive and
responsive design. In the classroom, students are just beginning to acknowledge the
existence of text-to-graphic AI, which allows them to experiment with text-based design
options that allow them to quickly visualize and explore a wide range of site program
alternatives. Nevertheless, how do we manage the ethical and creative boundaries
within an academic setting? In a research context, methods supporting rapid
manipulation of both generated images and existing landscape photography represent
advances that allow for greater collaboration surrounding landscape design decisions
(Incorporating resilience strategies, protecting vernacular landscape elements that
support a sense of place, or representing new design proposals that modify the
landscape). These approaches allow stakeholders to gain remarkable advances in

influencing the design process through shared visualization development. However, as
with any emerging technology, practitioners, educators, and researchers need to
respond to the challenges presented by text-to-graphic AI by developing and testing
new design process models and public engagement techniques that can improve
landscape decision-making and streamline collaboration.

Presenter: Aaron Thompson
Assistant Professor
Department of Horticulture and Landscape Architecture
Purdue University
625 Ag Mall Drive
West Lafayette, IN 47906

Title: Developing Guidelines for Extension’s Use of ChatGPT and Other Generative AI
Tools.

AI in Extension
Dr. Masiuk is a member of ASHS and has agreed to speak.
Description: A new technological era marked by the advent of Artificial Intelligence
(AI), particularly generative AI and Large Language Models (LLMs) like ChatGPT has
necessitated the need to navigate this domain with a compass of ethicality, safety, and
effectiveness. Penn State’s experience developing guidelines for Extension’s use of
generative AI tools which will be shared and discussed.

Presenter: Michael Masiuk
Assistant Director – Horticulture Programs
Penn State Extension
342 Agricultural Administration Building
University Park, PA 16802

Panel: 30 minute panel with the above speakers, to allow time for Q&A and discussion.

Moderator

Milt McGiffen

Speakers

Kent D. Kobayashi

Associate Professor, TPSS Dept., Univ. of Hawaii at Manoa

Harland Patch

Penn State University

Dr. Harland Patch focuses his current research on understanding the behavioral and molecular mechanisms associated with pollinator host plant choice, and the structure of plant-pollinator communities. Dr. Patch is also involved in ongoing projects to determine the interacting causes... Read More →

Kathryn Orvis

Professor, Purdue Univ

Yanqiu Yang

PhD candidate, The Pennsylvania State University

Yanqiu YangFounder & AI Lead Engineer at bioWatch | PhD Candidate at PSU | President-Elect of the Ag & Bio Engineering Graduate Student Council (GSC)Hi there! I’m Yanqiu, and I’m on a mission to bring cutting-edge technology to the fields and orchards. As the Founder & AI Lead... Read More →

Aaron Thompson

Michael Masiuk

Tuesday September 24, 2024 4:00pm - 6:00pm HST
Coral 3

Colloquium

SUBJECT Technology, Growth Chambers and CE, Teaching

7:59am HST

Growth Chambers and Controlled Environments 2 (CE 2)

Wednesday September 25, 2024 7:59am - 10:00am HST

Coral 2

Will Increasing the Potassium to Nitrogen Ratio Benefit Hydroponic Strawberry Production? - Jonathan Ries
Impact of Diurnal Chilling on Vegetative and Floral Development of Strawberry (Fragaria x annanassa) cvs. ‘Albion’, ‘Chandler’, ‘Monterey’, ‘Sensation’ Tray Plants in a Controlled Environment - Michael Palmer
Utilizing Controlled Environment Agriculture to Enhance the Yield and Flavor of Strawberries - Nicholas Cooley
Impact Of Elevated CO2 And Two Daily Light Integrals on the Production Efficiency of Strawberry (Fragaria × ananassa ‘Monterey’) Daughter Plants - Samson Humphrey
Unraveling Strawberry Stock Plant Architecture, Morphology, and Tips’ Spatial Distribution under Three Photoperiods to Facilitate Future Propagation System Design: A Comparative Study on Monterey as a Long-day Cultivar - Moein Moosavi
Stratified Wood Substrates for Optimizing Growth of Greenhouse-Grown Strawberries and Blueberries - Brandan Shur
Effect of Light Intensity on Strawberry Runner Tips Propagated Indoors - Lian Duron
Characterizing the Growth, Morphology, Productivity, and Fruit Quality of Twenty-five Strawberry Cultivars in Vertical Farm Environment - Yiyun Lin

Moderator

Yiyun Lin

The Ohio State University

Wednesday September 25, 2024 7:59am - 10:00am HST
Coral 2

Oral Sessions, Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

8:00am HST

CE 2 - Will Increasing the Potassium to Nitrogen Ratio Benefit Hydroponic Strawberry Production?

Wednesday September 25, 2024 8:00am - 8:15am HST

Coral 2

Strawberries (Fragaria × ananassa) are increasingly being grown in hydroponic systems, where effective nutrient management is critical for optimizing crop production and yield. Among essential mineral nutrients, potassium is a key nutrient that affect fruit quality in many fruiting crops. This study investigated how potassium to nitrogen (K:N) ratios regulate strawberry growth and development in a deep-water culture hydroponic system. We hypothesized that increasing the K:N ratios would enhance vegetative growth, fruit yield, and fruit quality. Bare-root plants of strawberry ‘Monterey’ and ‘San Andreas’ were grown indoor under a 23 °C air temperature and an 18-h photoperiod with an extended photosynthetic photon flux density of 350 µmol∙m–2∙s–1. The N level was kept constant at 77 ppm, while the study tested K:N ratios ranging from 1.5:1 to 4:5:1. Three weeks after nutrient treatments, strawberry plants showed similar crown number, crown diameter, leaf number, leaf area, and shoot dry mass regardless of K:N ratios in both cultivars. Increasing K:N from 1.5:1 to 4.5:1 linearly increased the root dry mass of Monterey’ but not in ‘San Andreas’. During the fruit production, K:N ratios did not affect the total number of fruits or total fresh mass of fruits. However, there was a linear decrease in the diameter, length, and fresh mass of individual fruits with increasing K:N ratio from 1.5:1 to 4.5:1 in both 'Monterey' and 'San Andreas'. Additionally, increasing K:N ratio from 1.5:1 to 4.5:1 slightly increased total soluble solids in ‘San Andreas’, but led to a greater increase in titratable acidity compared to the increase in total soluble solids in both ‘Monterey’ and ‘San Andreas’. These results suggest that increasing K:N ratios from 1.5:1 to 4.5:1 has little beneficial effect on overall plant growth, fruit yield and fruit quality for hydroponic strawberry production in deep-water culture systems.

Speakers

Jonathan Ries

Arizona State University

Co-authors

Yujin Park

Arizona State University

Wednesday September 25, 2024 8:00am - 8:15am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

8:15am HST

CE 2- Impact of Diurnal Chilling on Vegetative and Floral Development of Strawberry (Fragaria x annanassa) cvs. ‘Albion’, ‘Chandler’, ‘Monterey’, ‘Sensation’ Tray Plants in a Controlled Environment

Wednesday September 25, 2024 8:15am - 8:30am HST

Coral 2

In US open field nurseries, strawberry transplants for fruit production accumulate diurnal chilling hours (hours between -2 and 7°C) in the field prior to harvest and receive supplemental chilling as bare root plants in a cooler before being transplanted into a fruit production system. In nurseries in Northwestern Europe, tray plants are placed outside after rooting to accumulate diurnal chill hours and are moved into the cooler with leaves and substrate for supplemental chilling before being transplanted. The optimal amount of chilling varies among cultivars but is thought to contribute to a proper balance of vegetative vigor and floral development leading to best fruiting after transplanting into the production system. Climate change, labor cost and related issues cause problems in both nurseries and production. Therefore more and more growers and start-up companies venture into controlled environment production systems. Due to high cost, these systems require transplants that are optimally conditioned for early flowering. We evaluated the impact of diurnal chilling on vegetative and floral development of 250 cc strawberry tray plants in a controlled environment. 28 day old ‘Albion’, ‘Chandler’, ‘Monterey’, and ‘Sensation’ rooted daughter plants were moved into growth chambers where they received 0 (15°C 24 hours), 100 (4°C, 16°C), 250 (4°C, 19°C), or 450 (4°C, 24°C) chill hours over a six week period. Within each treatment, the same amount of chill hours were applied each day for the six week period. Among treatments, the non-chill temperature increased as the number of chill hours increased to ensure the same daily average temperature of 15°C. Chambers were fixed at 50% RH, 450 ppm CO2, 130-40 µmol m-2 s-1 for all treatments and a 12 hour photoperiod for ‘Chandler’ and ‘Sensation’ and a 16 hour photoperiod for ‘Albion’ and ‘Monterey’. After the treatment, all plants were dissected under the microscope to determine the number and development of floral meristems (flower mapping). Our results show that the plants in the 100 and 250 hour treatments produced more floral meristems and branch crowns than the 0 and 450 hour treatments across all cultivars. Additionally, in ‘Albion’ and ‘Monterey’, the plants of the 100 and 250 hour treatments had greater fresh mass and higher crown diameter than the plants in the 0 and 450 hour treatments. Finally, all cultivars except ‘Sensation’ had more flowers on plants in the 100 and 250 hour treatments than those of the 0 and 450 hour treatments.

Speakers

Michael Palmer

North Carolina State University

Co-authors

Mark Hoffmann

North Carolina State University

Wednesday September 25, 2024 8:15am - 8:30am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

8:30am HST

CE 2 - Utilizing Controlled Environment Agriculture to Enhance the Yield and Flavor of Strawberries

Wednesday September 25, 2024 8:30am - 8:45am HST

Coral 2

Presentation: Oral ASHS 2024 Keywords: CEA, greenhouse, Fragaria ×ananassa, temperature Utilizing Controlled Environment Agriculture to Enhance the Yield and Flavor of Strawberries Nicholas Cooley, Joshua Vanderweide, and Roberto Lopez In the U.S., strawberries (Fragaria ×ananassa) are the most popular berry fruit with a value of $2.8B. In 2022, strawberries experienced 12% growth in annual sales, with the majority of field production occurring in California and Florida. To meet consumer demand for flavorful, fresh, local, and year-round fresh strawberries, the industry is expanding controlled environment (CE) production of day-neutral (everbearing) cultivars in greenhouses and indoor farms. Within CEs, growers can potentially meet these demands through the manipulation of environmental parameters such as temperature, light, vapor pressure deficit, and carbon dioxide concentration. Despite the recent growth, CE growers are reporting low profitability. This imbalance of production and profitability stems from high energy costs, supra-optimal greenhouse temperatures during parts of the year, and low yield from the industry standard cultivar ‘Albion’. For producers to be considered profitable, they must reach an approximate annual yield of 15 kg∙m–2, which equates to a weekly yield of around 0.3 kg∙m–2. The objectives of our research are to 1) quantify the yield of other day-neutral cultivars in greenhouses; 2) determine how day and night temperature influence yield and fruit quality parameters; and 3) develop a model to predict the cardinal temperatures of each cultivar. Three cultivars, ‘Albion’, ‘Cabrillo’, and ‘Monterey’ were grown at day/ night temperatures (12 h/ 12 h) of 15/7, 18/10, 21/13, 24/16 or 27/19 °C, under a 16-h photoperiod, and a target DLI of 15 mol·m–2·d–1. Fruits were harvested three times weekly and at harvest, berry weight, diameter, color, shape, distortion, brix content, and flavor-related volatile organic concentrations were recorded. After 12 weeks of harvest, the highest average weekly yield was 0.17, 0.19, and 0.24 kg∙m–2 for ‘Albion’, ‘Cabrillo’ ‘Monterey’ at 18/10, 24/16, and 24/16 C, respectively. While the highest combined overall yield for all three cultivars was at 24/16 °C, the highest average berry weight differed. At day and night temperatures of 18/10, 18/10, and 15/7 °C, ‘Albion’, ‘Cabrillo’, and ‘Monterey had the highest average berry weights, respectively. Our results collectively indicate there are higher yielding day-neutral cultivars than the industry standard ‘Albion’.

Speakers

Nicholas Cooley

Michigan State University

Wednesday September 25, 2024 8:30am - 8:45am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

8:45am HST

CE 2 - Impact Of Elevated CO2 And Two Daily Light Integrals on the Production Efficiency of Strawberry (Fragaria × ananassa ‘Monterey’) Daughter Plants

Wednesday September 25, 2024 8:45am - 9:00am HST

Coral 2

Abstract: Strawberry nurseries face many challenges, and are considering controlled environment propagation as an alternative to conventional open-field propagation. Limiting factors to economic feasibility include stock plant yield (number of daughters produced per stock plant). From published research we know that increasing CO2 concentration and light intensity increases strawberry photosynthetic rate, however there has been no research on the effects of these treatments on the total stock plant yield of daughters. Our hypothesis is that higher light intensity and CO2 concentrations will improve plant growth and lead to greater total daughter plant production. The objective of this experiment is to increase stock plant yield by increasing CO2 concentration (500, 850, and 1200 μmol mol-1) and light intensity (DLI 14.4 and 28.8 mol m-2 d-1). Strawberry (Fragaria × ananassa Duch., ‘Monterey’) stock plants were transplanted into three controlled environment growth chambers, under combinations of CO2 and DLI treatments in a split plot design under 26°C, 65% relative humidity, and a 16-hour photoperiod. The stock plants were grown under treatment conditions for 70 days, and newly-formed daughters were logged every day. At the end of the experiment the stock plants and their daughter plants were harvested, and each daughter plant was evaluated based on its size (number of leaves, leaf area, and fresh/dry mass). Increasing CO2 concentration linearly increased stock plant yield, leading to 23.96% more daughter plants per mother plant from the 500 to the 1200 μmol mol-1 treatment. Plants under higher light intensity (500 μmol m-2 s-1) had 38% higher stock plant yield than those under 250 μmol m-2 s-1. These data support our hypothesis that increasing CO2 concentration and light intensity increase the total yield of daughter plants produced per stock plant. By optimizing CO2 concentration and light intensity, strawberry nurseries may be able to grow more daughter plants more efficiently in controlled environment nurseries than in the conventional open-field system.

Speakers

Samson Humphrey

NCSU

N/A

Co-authors

Ricardo Hernandez

North Carolina State University

Wednesday September 25, 2024 8:45am - 9:00am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

9:00am HST

CE 2 - Unraveling Strawberry Stock Plant Architecture, Morphology, and Tips’ Spatial Distribution under Three Photoperiods to Facilitate Future Propagation System Design: A Comparative Study on Monterey as a Long-day Cultivar

Wednesday September 25, 2024 9:00am - 9:15am HST

Coral 2

The US strawberry industry needs healthy, high-quality transplants every year for fruit production. Following the challenges in open-field nurseries, research is focused on controlled-environment agriculture as a potential alternative to not only increase strawberry tip yield but also to produce healthier, virus-free transplants (rooted tips). Growing stock plants indoors where the runners grow vertically downward increases the yield and quality of tips, however, there is a lack of information on the general architecture of plants especially the spatial distribution of daughter plants and also the leaf area index (LAI) distribution of the daughter plants’ canopy in the growing space. This information is vital for future system design as it determines the distance between the shelves and the potential need for intracanopy lighting. Furthermore, besides temperature, photoperiod strongly affects the trade-off between runner Vs. flower production. Yet, there is also a lack of information on how photoperiod will change the yield, quality, and architecture of stock plants in CEA, specifically on long-day cultivars. Here, we examined 12, 16, and 20 h photoperiods with the same DLI of 26 mol m-2 d-1 on ‘Monterey’ as a long-day cultivar with two replications in time. The chamber environment was maintained at a high temperature of 26 °C, ambient CO2, and 65% relative humidity. The plant density was 9 plant m-2. Following 64 days of growth, parameters related to yield, architecture, and quality were recorded. Results showed that even under relatively high temperatures, with shortening the photoperiod, a linear increase in the number of tips was observed, increasing from ~36.3 to ~44.3 (18%) with the same DLI. Regardless of the photoperiod, the highest proportion of tips (30.8%) were harvested on the runners from 40 – 80 cm distance from the mother plant, though the highest LAI (53.2%) was recorded on the tips from 0 – 40 cm, causing a sudden drop (92.8%) in the light intensity after 40 cm where most of the tips are growing. This information shows the need for intracanopy lighting under 40 cm depth from the mother plants. Around 98% of the tips were harvested from 0 – 160 cm, showing the needed space for the growth of runners (i.e., the distance between the shelves). Several morphology and photosynthetic parameters were also recorded. The information from this study will be used as a base for a follow-up experiment comparing top versus intracanopy lighting.

Speakers

Moein Moosavi

NC State University

https://www.linkedin.com/in/moein-moosavi-nezhad/

Co-authors

Ricardo Hernandez

NC State University

Wednesday September 25, 2024 9:00am - 9:15am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

9:15am HST

CE 2 - Stratified Wood Substrates for Optimizing Growth of Greenhouse-Grown Strawberries and Blueberries

Wednesday September 25, 2024 9:15am - 9:30am HST

Coral 2

As the demand for locally grown produce, particularly fresh fruits like blueberries and strawberries, continues to surge, the imperative for year-round production becomes increasingly evident. While these fruits are globally recognized for their extended-season production potential in controlled environments, the intricate environmental factors crucial for improved production and profitability remain partially understood, including the impact of soilless substrates. Amid growing concerns about the availability of internationally sourced substrates, such as coconut coir, this study explores an alternative approach to reduce reliance on such components, particularly in the cultivation of two small fruits rapidly integrated into controlled environments. Substrate stratification, involving the vertical layering of substrates within a single container, has shown promise in nursery and greenhouse settings, enhancing resource efficiency in terms of water and fertilizer inputs. However, no research has assessed the application of stratified substrates for fruit crops with the specific aim of reducing coir inputs in greenhouse production. Thus, the objective of this study was to investigate whether stratifying coir over low-cost, hammer-milled processed tree fiber could effectively decrease coir usage, dependency, and associated costs within the controlled environment fruit production industry. 'Albion' strawberries and 'Star' blueberries were cultivated in five substrate treatments, ranging from 100% coir to various stratified layers beneath coir, including 25%, 50%, and 75% coir compositions, as well as a 100% processed tree fiber treatment. Results suggest that employing substrate stratification enhanced plant growth for both fruit crops, indicating its potential utility in optimizing controlled environment fruit production while reducing reliance on costly substrate materials like coir. Further analysis will elucidate the full implications of this innovative approach on production efficiency and profitability.

Speakers

Brandan Shur

North Carolina State University

Co-authors

Brian Jackson

NC State

Wednesday September 25, 2024 9:15am - 9:30am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

9:30am HST

CE 2 - Effect of Light Intensity on Strawberry Runner Tips Propagated Indoors

Wednesday September 25, 2024 9:30am - 9:45am HST

Coral 2

Indoor propagation systems that use sole-source lighting in controlled environments can facilitate year-round production of disease-free, uniform strawberry liners. However, optimal conditions to propagate strawberry runner tips indoors are unknown. Runner tips of ‘Albion’ and ‘Fronteras’ strawberries were propagated indoors for 28 d under four photosynthetic photon flux density (PPFD) treatments: 75, 150, 225, or 300 ± 5 μmol·m–2·s–1 provided for 24 h·d–1 by white light-emitting diode fixtures. Runner tips were also propagated in a shaded greenhouse under mist. After propagation, plants were moved to a common greenhouse compartment and grown for 7 weeks to evaluate carryover effects on fruit yield (‘Albion’) or daughter-plant production (‘Fronteras’). Treatment responses were similar for both cultivars, except that shoot dry mass (DM) of ‘Fronteras’ followed a quadratic response with increasing PPFD, which peaked at 225 μmol·m–2·s–1. In contrast, shoot DM of ‘Albion’ linearly increased with increasing PPFD. Root DM of both cultivars also followed an increasing response with PPFD. However, there were no treatment differences in the number of shoots produced per plant or the length of the longest root. Interestingly, plants propagated under ≥150 μmol·m–2·s–1 had several dead shoots (up to 20%), likely attributed to plant stress. After the carryover phase, ‘Albion’ propagated under 225 or 300 μmol·m–2·s–1 were statistically different and produced the lowest fruit fresh mass compared to those grown in the greenhouse, whereas values were similar among plants propagated in the greenhouse or indoors under 75 or 150 μmol·m–2·s–1. No treatment differences were measured in the number of daughter plants produced by ‘Fronteras’. These findings suggest that although higher PPFD indoors promoted rooting and growth, plants propagated in the greenhouse were likely better adjusted to the dynamic greenhouse environment, which enabled them to reach the same growth and development of indoor-propagated plants at the end of the carryover phase.

Speakers

Lian Duron

Purdue University

Wednesday September 25, 2024 9:30am - 9:45am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

9:45am HST

CE 2 - Characterizing the Growth, Morphology, Productivity, and Fruit Quality of Twenty-five Strawberry Cultivars in Vertical Farm Environment

Wednesday September 25, 2024 9:45am - 10:00am HST

Coral 2

As the interest in strawberry production in controlled environment agriculture is ascending, the demand for cultivars that yield premium-quality fruit is rising. To identify strawberry suitable for vertical farm production, 25 strawberry (Fragaria × ananassa) cultivars were selected for premium flavor from USDA National Clonal Germplasm Repository. Fruit productivity and quality traits, plant vegetative phenotypes, and photosynthetic rates were evaluated using strawberries grown in a walk-in growth chamber where photoperiod altered between short day and long day to promote flowering and fruit production. Our results show that strawberry ‘Mara des Bois’ produced the earliest harvest, and ‘Hood’ had the highest maximum productivity coefficient. The largest fruit was produced by ‘Chandler’, and the reddest fruit was produced by ‘Marshall’. Among the 25 cultivars, 11 exhibited fruit Brix levels above 0.9, and 3 had a fruit Brix:TA ratio of 1.0. Ongoing fruit flavor analysis aims to identify unique flavor compounds within these strawberries. Correlations linked time to first harvest and maximum productivity coefficient with canopy area, shoot height, and photosynthetic rate per plant, revealing the intricate sink-source dynamics in strawberry plants. Interestingly, no correlation was found between maximum productivity coefficient and any fruit quality trait, challenging the commonly held belief in the constant competition between crop productivity and quality. The information of strawberry growth and production in vertical farm environment provided in this study can assist indoor growers in cultivar selection and potentially contribute to future strawberry breeding programs.

Speakers

Yiyun Lin

The Ohio State University

Co-authors

Changhyeon Kim

The Ohio State University

Chieri Kubota

The Ohio State University

Jim Oliphant

US Department of Agriculture

Michael Hardigan

US Department of Agriculture

Nahla Bassil

US Department of Agriculture

Wednesday September 25, 2024 9:45am - 10:00am HST
Coral 2

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

12:19pm HST

Growth Chambers and Controlled Environments - (CE)

Wednesday September 25, 2024 12:19pm - 1:40pm HST

Coral 1

Urban Agriculture Efficiency: A Year-Long Evaluation of Kale Yield and Energy Use in a Shipping Container Farm - Skyler Brazel
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila
Production of Red Leaf Lettuce at Vertical Farm Equipped with Blue LED According to Anthocyanin Concentration and Its Gene Analysis - Junjira Satitmunnaithum
Interlighting Improves Tomato Yield in Northern Greenhouses - Meriam Karlsson
Assessing the Impact of UV-C Treatment on Growth Parameters and Nutrient Levels in Hydroponic Systems for Romaine Lettuce Cultivation - Markanna Moore
Effect of low root-zone temperature and UV radiation on growth and gene expression of secondary metabolite pathways in Nicotiana benthamiana - KiHo Son
Effects of Short-Wavelength UV-B, UV-A, and Blue Light on the Rose Flower Color Transition Phenotype - Navdeep Kaur
Arduino Uno Can Reliably Log Substrate Moisture from a Bus of Digital Sensors and Control a Drip-Irrigation System - Stephanie E Burnett
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Wednesday September 25, 2024 12:19pm - 1:40pm HST
Coral 1

Poster Session, Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:20pm HST

CE - Urban Agriculture Efficiency: A Year-Long Evaluation of Kale Yield and Energy Use in a Shipping Container Farm

Wednesday September 25, 2024 12:20pm - 12:30pm HST

Coral 1

Urban expansion is a threat to agricultural land. As cities increase in size and residential areas are being built on arable land, a new solution to growing food in urban area needs to be considered. Shipping container farms are designed to grow a high number of plants in a small area. These farms are programmable to fit the environmental parameters that are optimal for each type of crop. In this experiment, ‘Toscano’ kale was grown inside the farm and harvested weekly for one year to simulate farm production. The average day/night temperature in the farm was 22.8C and 15.6C with a photoperiod of 20 hours. Sole sourced lighting was supplied by light emitting diodes with an 80:20 red:blue ratio and an intensity of 100 mol . m -2. s -1 for a daily light integral of 7.2 mol . d -1 . Electrical energy use of the farm was collected on three categories of energy usage: Lighting, HVAC, and all Other Energy usage. Seeds were sown four weeks prior to transplant. Plants were transplanted weekly into vertical channels and harvested 12 weeks after sowing. This experiment was a complete block design with block nested in time. Yield data was collected at time of harvest, including plant number, fresh mass, dry mass, plant height, canopy area, and leaf number. The mean number of plants per replication was 320. The mean fresh mass per plant by block was 43.34g, 48.84g, 53.17g, 59.15g, 57.88g, and 53.29g, respectively, while mean dry mass was 3.31g, 3.66g, 3.94g, 4.42g, 4.3g, and 4.08g, respectively. Daily mean lighting and other energy consumption exhibited no variation across all 48 harvests. Daily mean HVAC energy consumption varied based on outdoor environmental conditions, with increased usage during summer months and a maximum of 33.53 kWh/day. Overall, fluctuations across mean fresh mass needs to be investigated further as the optimal harvest date for this farm may occur prior to 12 weeks, for both plant yield and energy consumption levels.

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Carl Sams

University of Tennessee

Katelynn Rector

University of Tennessee - Knoxville

Wednesday September 25, 2024 12:20pm - 12:30pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:30pm HST

CE - Production of Red Leaf Lettuce at Vertical Farm Equipped with Blue LED According to Anthocyanin Concentration and Its Ge

Wednesday September 25, 2024 12:30pm - 12:40pm HST

Coral 1

At the last ASHS annual conference, I, Satitmunnaithum et al., (2023), presented our study on the effect of blue and white LED light ratio on red leaf lettuce, however, the effect of blue LED on red coloration during its growth is still unclear. Thus, at this year’s conference, we aim to clarify the mechanisms of red coloration under blue LED based on anthocyanin biosynthesis gene analysis and its content in vertical farming condition to stabilize its production for high market demand. To elucidate the effect of blue LED light on the red coloration of red leaf lettuce, green and red leaf lettuce (Lactuca sativa L.) were selected for this study. Both were hydroponically cultivated at the Advanced Plant Factory Research Center at Meiji University, Japan. The cultivation temperature was set at 22 ℃ with a humidity of 60%. Seeds were sown under white LED for 24 hours. Ten-day-old seedlings were transplanted to different light conditions: white LED and blue LED. The photoperiod was set for 16 hours. The nutrient solution was supplied at an EC of 1.6 mS/m^2 with a pH of 6.0 ± 0.5. Both light treatments had a PPFD of 100-120 µmol/m^2/s. After 20, 25, and 30 days of transplantation, lettuces were harvested. The red area on leaf lettuce, along with the total anthocyanin content and its precursors, as well as the expressions of anthocyanin biosynthesis-related genes such as ANS, CHS, bHLH, DFR, and HY5, were evaluated. Blue light shows a large red area on red leaf lettuce at most of the development stages resulting in a high red area percentage, while green leaf lettuce remained completely green in both light conditions. The interested genes were upregulated mostly in blue light irradiated red leaf lettuce which led to high total anthocyanin content. This can be assumed that blue LED light enhances anthocyanin synthesis in red leaf lettuce which can contribute to the stable production of red leaf lettuce in vertical farms.

Speakers

Junjira Satitmunnaithum

Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University , Japan

Co-authors

Chiharu Inoue

Daiwa House Co. Ltd.,

Takao Otsuka

Daiwa House Co. Ltd.,

Takashi Ikeda

School of Agriculture, Meiji university

Wednesday September 25, 2024 12:30pm - 12:40pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:35pm HST

Exhibitor Talk: Conviron

Wednesday September 25, 2024 12:35pm - 12:50pm HST

Coral 5

This year Conviron is launching three new products:
• GEN1000-ECO (introduction date: April 16, 2024)
• ConvironDirect (introduction date: March 4, 2024)
• PGR15/E15 LED Retrofit (introduction date: Jan 5, 2024)
GEN-1000-ECO:
The GEN1000-ECO is a new compact reach in chamber ideal for short and tall plant research that comes standard with humidity control and energy efficient features such as a smaller compressor and LED lighting - for up to 15% reduced energy consumption. Low, medium and high light options are available to meet a range of research requirements.
ConvironDirect:
ConvironDirect is a new premium software tool that enables users to manage chamber setpoints and actual conditions remotely through any building LAN connected desktop, notebook or handheld mobile device. ConvironDirect is ideal for users that have Conviron reach-in plant growth chambers or walk-in rooms and want a seamless connection to their chamber, their plants, and their data from virtually anywhere.
PGR15/E15 LED Retrofit:
Fluorescent lamps such as T5, T8 and T12 have been the standard for many years and have been used in tens of thousands of plant growth chambers around the world. However, fluorescent lighting is trending towards obsolescence and replacement lights are increasingly difficult to source economically. Conviron is now offering a retrofit for aged PGR15-E15 chambers to enable users to take advantage of the latest LED lighting technology and save up to 80% on energy costs.

Speakers

Caitlynn Kendrick

Wednesday September 25, 2024 12:35pm - 12:50pm HST
Coral 5

Hort Theater & Collaboration Center, Industry Related

SUBJECT Technology, Growth Chambers and CE, Hort Industry

12:40pm HST

CE - Interlighting Improves Tomato Yield in Northern Greenhouses

Wednesday September 25, 2024 12:40pm - 12:50pm HST

Coral 1

Low natural light and high heating costs limit northern winter greenhouse production. Technology advancements now offer opportunities to improve delivery of light to and within crop canopies. The greenhouse tomato cultivars Bigdena and Beorange were chosen to evaluate high pressure sodium irradiance with LED interlighting. Plants were grown in a high-wire drip irrigation system using dutch (bato) buckets (17.7 L volume) filled with a 50/50 mixture of perlite and a peatlite medium (Pro-Mix BX). The containers were placed in alternating rows across a drainpipe. Seeds were sown on 8 Sep and two seedlings were transplanted into each container 38 d later (17 Oct). Day temperature was 22 ± 2°C and reduced to 18 ± 2°C during the night. Lower leaves were removed as fruit ripened and the study was terminated at a plant height of ~250 cm (128 d from transplanting). The photoperiod was 18-h. In addition to overhead 400-W HPS lighting, LED fixtures designed for placement within the canopy were evaluated (GE current Arize® Integral). Two horizontal LED bars were positioned 30 cm (12 inches) apart with the upper bar adjusted within 30 cm of the top of the plants throughout the study. The integral lighting provided a spectrum with blue (peak 450 nm) and red (peak 660 nm) wavelengths in a 12:88 ratio. The perpendicular horizontal distance from the LED bars to the plant stems was 30 to 35 cm. The intensity (400-700 nm) measured at the plant stems horizontally from the LEDs averaged 195 ± 30 µmol m-2s-1. Overhead HPS provided ~130 ± 20 µmol m-2s-1, 100 cm below the fixtures. Seasonally short days and low sun angles limited natural light during the study. The first ripe tomatoes were harvested 62 d from transplanting (18 Dec). Interlighting resulted in higher plant yields with 6.3 ± 0.82 kg for Bigdena and 4.9 ± 0.67 kg for Beorange. In comparison, 4.1 ± 0.37 kg (Bigdena) or 3.4 ± 0.80 kg (Beorange) was recorded for plants receiving only HPS lighting. Five or six additional tomatoes were harvested with interlighting for Bigdena (25 ± 2.0 versus 19 ± 1.8) and Beorange (22 ± 2.5 versus 17 ± 1.9). Average tomato size increased from 217 ± 11.9 g to 250 ± 19.3 g (Bigdena) or from 199 ± 36.1 g to 227 ± 20.2 g (Beorange) with interlighting.

Speakers

Meriam Karlsson

University of Alaska Fairbanks

Co-authors

Eric Cook

University of Alaska Fairbanks

Wednesday September 25, 2024 12:40pm - 12:50pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:50pm HST

CE - Assessing the Impact of UV-C Treatment on Growth Parameters and Nutrient Levels in Hydroponic Systems for Romaine Lettuc

Wednesday September 25, 2024 12:50pm - 1:00pm HST

Coral 1

Introduction: Preliminary studies have shown that ultraviolet treatment is able to reduce microbial contamination in the nutrient water of hydroponic systems. However, it is not known how these ultraviolet treatments may impact nutrient water chemistry or crop growth and yield. Purpose: The objective of this study is to examine the impact of an ultraviolet light treatment on romaine lettuce growth parameters and nutrient levels in the treated hydroponic water. Methods: Commercially-available DWC (Deep Water Culture) hydroponic systems were used to grow romaine lettuce (Latticua lettuceia var. Sparx) in a two-part nutrient solution (Hydro-Gro Leafy and calcium nitrate). The electrical conductivity (EC) was maintained between 1.6 and 1.8 mS/cm during the study. The nutrient solution was treated with a UV-C device (MiniPure MIN-1; 500ml capacity) emitting peak irradiance at 254nm at flow rates of 0, 3 and 6 L/min. Water samples were collected before and after each treatment and the experiment will be repeated twice for a total of three times. Twice weekly during the six-week growth period, parameters including plant height, SPAD value, and chlorophyll fluorescence were measured. At the end of the production, fresh weight and dry weight of each plant sample were measured. Results: Low and high UV doses resulted in 1.17 and 1.36 log reductions of Escherichia coli in hydroponic nutrient water. Preliminary findings for the effect of UV light on the concentration of nutrients (NPK) yielded no significant difference in the nutrient level. The study is underway for assessing the effect on the lettuce growth parameters and therefore we are not reporting any results on the crop growth parameters. Significance: UV light technology at optimized dosage levels has the potential to improve the safety of hydroponic systems with minimal effect on the plant growth and nutrient water.

Speakers

Markanna Moore

Kansas State University

Co-authors

Eleni Pliakoni

Kansas State University

Majid JaberiDouraki

Kansas State University

Manreet Bhullar

Kansas State University

Teng Yang

Kansas State University

Wednesday September 25, 2024 12:50pm - 1:00pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:00pm HST

CE - Effect of low root-zone temperature and UV radiation on growth and gene expression of secondary metabolite pathways in N

Wednesday September 25, 2024 1:00pm - 1:10pm HST

Coral 1

This study explored the effects of low root-zone temperature (LT) and UV radiation (UV) alone and combined on changes in growth, transcription, and gene expression related to secondary metabolite in Nicotidana benthamiana. The plants were grown in a controlled environment (25/20°C, 16/8 h [light/dark], 70% relative humidity, 1,000 µmol·mol−1 CO2 with photosynthetic photon flux densities of 100 and 200 µmol·m−2·s−1 for 10 and 18 d, respectively). Twenty-eight days after sowing, the seedlings were treated with LT (15°C), 0.3 W·m−2 of UV radiation, and a combined treatment with LT and UV (LT*UV) for 3 d. Results found that the treatment with UV alone decreased the quantum efficiency of photosystem II by approximately 1.5 times, and most growth characteristics decreased under the UV (approximately 1.5 times) and LT*UV treatments. Combined treatment with LT*UV significantly inhibited the growth characteristics and photosynthetic rates compared to those under the single LT and UV treatments. In particular, the transcriptome levels of phenylpropanoid and flavonoid biosynthesis were the most significantly affected by LT*UV. This suggests the potential of using LT treatment in hydroponic systems and UV radiation to control the synthesis of health-promoting compounds of secondary metabolites in greenhouses and controlled-environment agricultural facilities.

Speakers

KiHo Son

Gyeonsang National University

Co-authors

Eiji Goto

China university

Wednesday September 25, 2024 1:00pm - 1:10pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:10pm HST

CE - Effects of Short-Wavelength UV-B, UV-A, and Blue Light on the Rose Flower Color Transition Phenotype

Wednesday September 25, 2024 1:10pm - 1:20pm HST

Coral 1

Light quality plays a crucial role in the growth and development of plants. In this study, we aimed to assess the effects of short-wavelength light on rose genotype '16401-N055’, which exhibits the flower color transitioning trait: the flowers change colors from yellow to pink in sunlight. Roses that exhibit this flower phenotype are termed transitioning-type roses. Specifically, we analyzed and compared the impact of six different light treatments [a sunlight control in open field and five spectral treatments created using light-emitting diodes (LEDs)] on various physiological and morphological characteristics. The five LED treatments included white light, blue light, UV-A white light, UV-B white light, and 80% blue 20% white light. Each treatment had two replications where one-year-old rose plants were the experimental unit. The total light intensity was maintained at 300-350 micromol m-2 s-1 for a photoperiod of 16 h light and 8 h darkness. The morphological traits measured included height, width, number of buds, number of flowers, and node density. The color scale parameters L* [luminance of the color ranging from 0 (black) to 100 (white)], a* [red (positive values) and green (negative values) color levels], and b* [yellow (positive values) and blue (negative values) color levels] were measured using a colorimeter. Additionally, the chlorophyll concentration index (CCI) was measured using a chlorophyll meter. Fully pigmented pink flowers were only observed in the UV-B white light treatment with an average L* value of 44.1 and a* value of 50.6. A slight pink hue was observed on the outer sections of petals in blue and blue white light treatments. The average L* and a* values of flowers in the blue treatment were 87.21 and 6.24, and in blue white treatment were 90.9 and 1.86, respectively. The flowers in the white UV-A treatment remained white with the highest average L* value of 92.4 and the lowest average a* value of -1.86. The CCI of plants under sunlight (23.5) was significantly lower than the plants treated with blue (34.4), and blue white (33.7) light. No significant differences in morphological traits were detected after two weeks. The plants will be monitored for longer periods and more data will be collected every two weeks for one month to document additional changes. The results obtained will provide additional information on morphological and floral changes in this genotype under different light treatments.

Speakers

Navdeep Kaur

Texas A and M university

Co-authors

David Byrne

Texas A and M University

Oscar Riera-Lizarazu

Texas A and M University

Shuyang Zhen

Texas A and M University

Wednesday September 25, 2024 1:10pm - 1:20pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:20pm HST

CE - Arduino Uno Can Reliably Log Substrate Moisture from a Bus of Digital Sensors and Control a Drip-Irrigation System

Wednesday September 25, 2024 1:20pm - 1:30pm HST

Coral 1

Inexpensive Arduino microcontrollers can be programmed to operate and log data from environmental sensors and operate other accessories such as irrigation solenoids. We describe our efforts to build a modified version of Arduino Uno systems previously developed at the University of Georgia, which operated analog moisture sensors and opened solenoid valves to drip emitters when moisture fell below user-defined thresholds. We attempted to 1) replace analog sensors with a bus of digital sensors that use the SDI-12 communication protocol, 2) include programming to parse digital output from two popular SDI-12 sensors (Decagon GS3 and Campbell Scientific 5TM), 3) use 12VDC solenoid valves that were less expensive and smaller (1/2”) than alternatives, and 4) overcome several challenges encountered in the construction and programming of the Arduino-based system. These included an approach to more easily manage the connection of numerous wires, the inclusion of a reversed diode at the solenoid terminals to prevent electrical interference from intermittently resetting the Arduino program, and the adoption of programming strategies to work around memory limitations that initially rendered our Arduino systems with digital sensors unreliable. We overcame these challenges to develop a robust, reliable, and easy-to-deploy Arduino-based environmental logger and automated drip-irrigation system that can operate numerous digital sensors. Sensor type and thresholds for volumetric water content are defined in a single location within the program, enabling the user to easily make minor adjustments to the system. We also included extensive line-by-line documentation of the source code. A list of the hardware used in this system is available. In 2023, eight of these systems operating 64 total sensors proved their reliability over a two-month experiment on the drought stress physiology of wetland shrubs. We conclude that this system is an effective solution for in-house sensor-automated irrigation with high customizability for end users.

Speakers

Stephanie E. Burnett

University of Maine

Co-authors

Adam J. Peterson

Unaffiliated

Bryan Peterson

University of Maine

Jessica Hutchinson

University of Maine

Rhuanito S. Ferrarezi

University of Georgia

Wednesday September 25, 2024 1:20pm - 1:30pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:30pm HST

CE - Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination

Wednesday September 25, 2024 1:30pm - 1:40pm HST

Coral 1

Spinach (Spinacia oleracea) is a nutritionally and commercially significant crop grown in controlled environments; however, its seeds are difficult to germinate in soilless culture. Excess moisture in the root zone can inhibit germination and impede seedling establishment. To address this, we conducted an experiment with a randomized complete block design (three replications) to identify the optimal moisture content for spinach ‘Space’ germination. In each of 63 sealed containers, we placed 20 seeds on a double-layered paper towel pre-moistened with varying amounts of reverse-osmosis water. We quantified visible germination percentages daily in response to seven moisture indices [moisture mass ÷ (paper mass moisture mass)] ranging from 50% to 94% over an 11-day period. Air temperature and relative humidity were 22.12 ± 0.02 °C and 34.35% ± 8.80%, respectively. The optimal moisture index was 80%, which resulted in the highest cumulative visible germination percentage (92%, which is close to the labelled 93% on the seed package). Deviating from the optimal moisture index in either direction decreased the germination percentage to 0%–22% and delayed germination by up to 5 days. The response of the cumulative visible seed germination percentage to the moisture index followed a normal distribution. The daily new visible germination percentage peaked on day 3 under most moisture indices; it was 55% under the optimal moisture index and < 24% under the other moisture indices. In conclusion, a moisture index of 80% resulted in the highest germination percentage (92%) and the fastest germination time (2–5 days) in spinach ‘Space’, whereas lower or higher moisture indices caused poorer (0%–67%), delayed, and less uniform germination. Once transplanted, the spinach seeds germinated with this moistened-paper method under the optimal moisture index adapt and perform well in soilless substrates, including rockwool, which is notoriously difficult to germinate spinach seeds in.

Speakers

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

Wednesday September 25, 2024 1:30pm - 1:40pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:59pm HST

Growth Chambers and Controlled Environments 3 (CE 3)

Wednesday September 25, 2024 1:59pm - 3:45pm HST

Coral 1

Effects of Light Sources and Fertilizers on Biomass Production of Nine Lettuce Cultivars in a Hydroponic Nutrient Film Technique System - Dario Rueda Kunz
Enhancing Lettuce Yield: Strategies for Fertility Management in Soilless Growth Systems. - Bryce Waugh
Effect of ZnO and SiO2 Nanoparticles on Growth and Physiology of Hydroponic Lettuce Under Salinity Stress - Chungkeun Lee
An Intermediate Calcium-mobilizing Biostimulant Concentration Controls Tipburn of Two Greenhouse Hydroponic Lettuce Cultivars Without Affecting Growth -Shem Msabila
Optimizing Sampling Methods for Sap Extraction to Enhance Plant Nutrient Analysis in CEA - Husnain Rauf
Effects of Potassium and Iron Supplements and Late Nitrogen Restriction on Aquaponic Taro (Colocasia esculenta) Corm Production - Andrew Bohringer
Advantages of a novel in situ pH measurement for soilless media - Hikari Skabelund

Moderator

Theodore Radovich

University of Hawai’i at Mānoa

Wednesday September 25, 2024 1:59pm - 3:45pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

2:00pm HST

CE 3 - Effects of Light Sources and Fertilizers on Biomass Production of Nine Lettuce Cultivars in a Hydroponic Nutrient Film Technique System

Wednesday September 25, 2024 2:00pm - 2:15pm HST

Coral 1

This study investigated the impact of two light sources and fertilizers on the growth of nine lettuce cultivars in a hydroponic nutrient film technique system. The research was prompted by reduced plant growth and acidity issues observed in the nutrient solutions in which Lettuce (Lactuca sativa cv. Salanova) was growing in previous experiments. The hypothesis posited that adjusting the ammonium/nitrate ratio in the nitrogen fertilizer source could mitigate acidity drops in the nutrient solution and consequently enhance biomass production. This experiment was conducted at Texas Tech University's Horticulture Gardens and Greenhouse Complex from October 10 to November 22, 2023. Treatments included combinations of two light sources (WhiteLEDs and LumiGrow TopLight Node™) and two fertilizer brands (Oasis and MaxiGro) containing different ratios of ammonium:nitrate; Oasis with 21.25:78.75, and MaxiGro with 15:85. Both fertilizers were maintained at the same concentration of nitrogen throughout the experiment, although the rates were changed according to developmental stage. The nutrient solutions initially contained 100 ppm N fertilizer for three weeks, followed by a water change and an increase to 150 ppm N.The pH and EC levels were closely monitored throughout the experiment. Results revealed significant differences among cultivars for all measured variables, with Salvius demonstrating superior performance in most aspects. The light source had no significant impact on aerial growth variables, while the MaxiGro fertilizer brand significantly and positively influenced plant weight, height, and root weight. Although there were significant interactions between light source, cultivar, and fertilizer for above-ground variables, these were highly dependent upon fertlizer. In conclusion, the choice of fertilizer brand is crucial for optimal lettuce growth in hydroponic systems. This study highlights the importance of selecting appropriate fertilizer characteristics to avoid detrimental effects on biomass production. Further trials are recommended to validate these findings and address concerns for home and commercial growers in hydroponic lettuce production.

Speakers

Dario Rueda Kunz

Texas Tech University

Co-authors

Catherine Simpson

Texas Tech University

Wednesday September 25, 2024 2:00pm - 2:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

2:15pm HST

CE 3 - Enhancing Lettuce Yield: Strategies for Fertility Management in Soilless Growth Systems.

Wednesday September 25, 2024 2:15pm - 2:30pm HST

Coral 1

The focus on sustainability and effective resource management is expanding along with the upward trend in greenhouse production. Precise application of fertilizers is becoming more and more important in a variety of agricultural systems. The physical and chemical characteristics of soilless growth media differ from those of soil, which causes differences in their ability to retain nutrients. As such, accurate rates of fertilizer are crucial. This study looked at 14 different fertilizer blends with varying percentages of potassium (0-200ppm), phosphorus (0-100ppm), and nitrogen (0-200ppm). Pots were filled with Berger BM6 media and then ‘Buttercrunch’ lettuce seeds were planted. With each treatment fertilizer rate, the plants were hand-watered once a week to maintain a 10% leaching fraction. The number of leaves, dry shoot weight, fresh root weight, dried root weight, and SPAD readings were among the end measurements. The study found that a mix of high rates of nitrogen, phosphorous, potassium fertilizer treatments increased fresh shoot weight. This emphasizes the need for additional study to determine the best fertilizer rates for various specialty crops grown in soilless greenhouse environment.

Speakers

Bryce Waugh

Grad Student, Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Wednesday September 25, 2024 2:15pm - 2:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

2:30pm HST

CE 3 - Effect of ZnO and SiO2 Nanoparticles on Growth and Physiology of Hydroponic Lettuce Under Salinity Stress

Wednesday September 25, 2024 2:30pm - 2:45pm HST

Coral 1

Nanoparticles have unique physical and chemical properties, which can positively and negatively impact crop growth and tolerance to abiotic stresses. This study evaluated the potential of ZnO and SiO2 nanoparticles in alleviating salinity stress in hydroponically cultivated lettuce. Two-week-old lettuce seedlings (Lactuca sativa cv. Green Forest) were transplanted into a 5-L deep water culture system and grown for four weeks in a customized growth chamber set at 25°C with 230 µmol/m2/s PPFD. The nutrient solution was maintained at an electrical conductivity (EC) of 1.5 dS/m and pH 5.8, and replenished weekly. A factorial design was employed with four salinity stresses (non-saline, 50 mM NaCl, 33.3 mM CaCl2, 25 mM NaCl 16.6 mM CaCl2) and three nanoparticle treatments (no nanoparticle, 100 ppm ZnO, 100 ppm SiO2). Under non-saline conditions, both ZnO and SiO2 treatments showed no significant differences in shoot growth compared to the control plants. However, ZnO application reduced shoot biomass, leaf area, SPAD, chlorophyll fluorescence and net photosynthetic rate under CaCl2 and NaCl CaCl2 stress. SiO2-treated plants had higher SPAD than the control plants under CaCl2 stress but presented lower values under NaCl CaCl2 stress. Root growth also showed contrasting results based on the stress conditions. SiO2 application resulted in increased root dry weight, total root length and surface area under non-saline and CaCl2 stress, while they decreased under NaCl stress. Similarly, ZnO application enhanced root growth under non-saline conditions, but demonstrated negative effects under all salinity stress conditions. In conclusion, SiO2 nanoparticle application did not improve salinity tolerance in lettuce, except for root growth under CaCl2 stress, and ZnO nanoparticle treatments showed phytotoxicity in both shoots and roots under all salinity stress conditions.

Speakers

Chungkeun Lee

Texas A&M University

Co-authors

Daniel Leskovar

Texas A

Seunghyun Choi

Texas A

Wednesday September 25, 2024 2:30pm - 2:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

2:45pm HST

CE 3 - An Intermediate Calcium-mobilizing Biostimulant Concentration Controls Tipburn of Two Greenhouse Hydroponic Lettuce Cultivars Without Affecting Growth

Wednesday September 25, 2024 2:45pm - 3:00pm HST

Coral 1

Lettuce (Lactuca sativa) tipburn is a physiological disorder that leads to unappealing browning or necrosis of young leaf tips and stems, caused by localized calcium deficiency. It negatively impacts crop quality and yield, making proactive management essential for achieving optimal production. The objective was to evaluate the efficacy of a calcium-mobilizing chemical biostimulant, applied in the nutrient solution, on lettuce growth and tipburn. We conducted a greenhouse experiment on two lettuce cultivars (‘Dragoon’ and ‘Rex’) using a randomized complete block design. The seedlings were grown indoors under continuous white light from light-emitting diodes (LEDs) with a mean daily light integral (DLI) of 26 mol⋅m−2⋅d−1. We transferred 11-day-old seedlings to deep-water-culture hydroponic trays in a greenhouse. The two cultivars were subjected to three replications and five biostimulant concentrations (BC) of 0 (control), 0.125, 0.25, 0.5, and 1 mL⋅L−1 of the nutrient solution. Plants were grown under an 18-h photoperiod with a mean DLI of 16.6 ± 2.0 mol⋅m−2⋅d−1 from both sunlight and supplemental white LEDs, an air temperature of 24.6 ± 3.1 °C, and relative humidity of 33.2% ± 9.5%. Plant data were collected 14, 21, 28, and 35 days after transplant (DAT). There was no visible tipburn 14 DAT; however, plant diameter and shoot mass (fresh and dry) decreased with increasing BCs. We observed tipburn 21 DAT in both cultivars. The control had the highest severity on a 0–5 scale (0 = no tipburn; 5 = severe tipburn) for ‘Dragoon’ (0.6) and ‘Rex’ (1.3), whereas no tipburn occurred under higher BCs (i.e., 0.5 and 1 mL⋅L−1). Tipburn progressed 28 DAT, when increasing the BC from 0 to 1 mL⋅L−1 decreased the tipburn rating from 3.3 to 0 for ‘Dragoon’ and from 4.1 to 0 for ‘Rex’. Plant growth was stunted under the highest BC (i.e., 1 mL⋅L−1). At 35 DAT, both cultivars had severe tipburn under the control but had decreasing tipburn severity as the BC increased. Plant growth was unaffected under the control and low BCs (i.e., 0, 0.125, 0.25 mL⋅L−1). Under the highest BC, ‘Dragoon’ had the longest roots, but ‘Rex’ had the shortest. In contrast, plants experienced phytotoxicity (reduced biomass and chlorophyll concentration) under the highest BC, i.e., (1 mL⋅L−1) though no tipburn was recorded. In conclusion, the optimal calcium-mobilizing BC was 0.5 mL⋅L−1, which minimized tipburn of greenhouse hydroponic lettuce without affecting biomass accumulation or causing phytotoxicity during later development stages.

Speakers

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

Wednesday September 25, 2024 2:45pm - 3:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

3:00pm HST

CE 3 - Optimizing Sampling Methods for Sap Extraction to Enhance Plant Nutrient Analysis in CEA

Wednesday September 25, 2024 3:00pm - 3:15pm HST

Coral 1

Plant sap analysis is a technique for monitoring plant nutrient status in real-time, enabling precise nutrient management to enhance growth and yield in controlled environment agriculture (CEA). Comprehensive sampling techniques are vital for accurate determination of nutrient concentrations, considering the variability of nutrients across different developmental phases of plants. However, questions remain regarding the selection of the appropriate plant tissues, including the number of leaves collected, sampling time, type and age of plant tissue, and frequency. Different crops need specific sampling procedures due to their unique leaf morphology, growth habits, and physiology. Many commercial laboratories only distinguish between new and old leaves. In this series of studies, we determined the most effective sampling method including the number of leaves, the type and age of tissue, as well as the timing and frequency of the collection. Optimal sampling techniques were identified for lettuce and tomato by conducting five different experiments across three cultivars. These experiments varied the number of leaves sampled (10, 20, 30 per sample with three replicates), types of tissue (leaves for lettuce with three replicates, and petioles and leaves for tomatoes with 20 each per sample), age of tissue (new vs. old with 20 leaves per sample and three replicates), time of collection (6, 8, 10 am with three replicates). For lettuce, two developmental stages (half and final harvest maturity), while for tomatoes, sampling frequency at four different growth stages was investigated (first fully expanded leaves, 1/3 and 2/3 of crop development, and final harvest). The results indicate that collecting 20 fully expanded leaves at 8 am, particularly at the final harvest, was considered the best sampling technique for nutrient analysis for both lettuce and tomatoes, providing the most effective sampling technique for optimizing nutrient management.

Speakers

Husnain Rauf

University of Georgia

Co-authors

Cristian Toma

Kalera

Daniel Jackson

University of Georgia

Jason Lessl

University of Georgia

Jessica Staha

Local bounti

Miguel Puebla

Pure flavor

Rhuanito S. Ferrarezi

University of Georgia

Timothy Coolong

University of Georgia

Zilfina Rubio

University of Georgia

Wednesday September 25, 2024 3:00pm - 3:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

3:15pm HST

CE 3 - Effects of Potassium and Iron Supplements and Late Nitrogen Restriction on Aquaponic Taro (Colocasia esculenta) Corm Production

Wednesday September 25, 2024 3:15pm - 3:30pm HST

Coral 1

The growing of taro in aquaponic systems has yielded corms significantly smaller than those grown terrestrially. Previous trials only partially supported the hypothesis that these low yields were due to excessive water and nitrogen levels late in vegetative development. A 2×2 (nitrogen restricted × supplemental fertilizer) factorial designed experiment was replicated 4 times in dual-tub systems. The 4 treatments tested were: 1) Fish effluent supplied throughout 10 months of plant development (T1); 2) Fish effluent restricted from the system at 6 months and fresh water supplied for the remaining 4 months of development (T2); 3) T1 plus supplemental potassium and iron fertilizer (T3); 4) Treatment 2 plus supplemental potassium and iron fertilizer (T4). The results indicate that the supplemental fertilizer was more important than effluent restriction late in development in enhancing corm growth, although effluent restriction did result in a higher maturity index of corms under supplemental fertilizer treatment. The corm yields were 140% higher in T3 (1.5 kg plant-1) than in T2 (0.63 kg plant-1). T4 had significantly more biomass partitioned into the corm (56% of total biomass) compared to T3 (44% of total biomass). The ratio of corm: total biomass is a key indicator of plant maturity and suggests restriction of high nitrogen effluent enhanced photosynthate translocation to the corm under supplemental fertilizer. Corm density was highest in T3 and lowest in T4, perhaps due to starch conversion to sugar in over-mature corms in T4. These results demonstrate the importance of supplementing potassium and iron fertilization, as well as restricting high nitrogen fish effluent late in taro corm development, to optimize taro yields and quality in aquaponic production systems.

Speakers

Andrew Bohringer

University of Hawai'i at Manoa

Co-authors

Bradley Kai Fox

University of Hawai'i at Manoa

Eric Collier

University of Hawai'i at Manoa

Koon-Hui Wang

University of Hawai'i at Manoa

Robert Paull

University of Hawai'i at Mānoa

Theodore Radovich

University of Hawai’i at Mānoa

Wednesday September 25, 2024 3:15pm - 3:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

3:30pm HST

CE 3 - Advantages of a novel in situ pH measurement for soilless media

Wednesday September 25, 2024 3:30pm - 3:45pm HST

Coral 1

Rhizosphere pH determines nutrient bioavailability, but this pH is difficult to measure. Standard pH tests require adding water to growth media. This dilutes hydrogen ion activity and increases pH. We used a novel, in situ, pointed-tip electrode to estimate rhizosphere pH without dilution. Measurements from this electrode matched a research-grade pH meter in hydroponic nutrient solutions. We then compared measurements from this electrode to saturated paste and pour-through methods in peat moss, coconut coir, and pine bark. The pointed-tip electrode was unable to accurately measure pH in the highly-porous pine bark media. Adding deionized water to the other media at container capacity using the saturated paste method resulted in a pH that was 0.59 ± 0.30 units higher than the initial in situ measurement at the top of the container. This increase aligns with established solution chemistry principles. Measurements of pH using the pour-through method were 0.38 ± 0.24 pH units higher than in situ measurements at the bottom of the container. We conclude that in situ pH measurements are not subject to dilution and are thus more representative of the rhizosphere pH than the saturated paste and pour-through techniques.

Speakers

Hikari Skabelund

Texas A

Co-authors

Bruce Bugbee

Utah State University

Noah Langenfeld

Utah State University

Royal Heins

Utah State University

Wednesday September 25, 2024 3:30pm - 3:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

4:00pm HST

AI Innovation for Horticulture - Part 2

Wednesday September 25, 2024 4:00pm - 6:00pm HST

Coral 3

Introduction and Overview

Speaker: Kathryn Orvis
Professor
Department of Horticulture and Landscape Architecture
Purdue University
625 Ag Mall Drive
West Lafayette, IN 47907-2010

Title: Digital Agriculture and AI on Specialty Crops Production

Description: Digital agriculture is the 4th agricultural revolution and Artificial Intelligence (AI) is part of it. Currently, in the "connected agriculture"; era, many technologies have been released on the marked regarding the use of multispectral
sensors for many purposes in agriculture. This talk is going to cover information on how to use Digital Agriculture online platforms to process multispectral imagery, and how AI can be used to collect individual in-field plant data.

Speaker: Luan Pereira de Oliveira
Assistant Professor and Precision Agriculture Extension Specialist
Department of Horticulture
University of Georgia
139 Engineering Building
2329 Rainwater Road
Tifton, GA 31793

Title: Bringing the Future of AI to the Farm.
Description: In this talk, we will cover the multitude of use cases where AI can be applied in farming – from weed detection and robotics to Generative AI-based farm assistants and Virtual Reality. We go through the industry trends of applied Artificial Intelligence and think big about farm automation for the future.

Speaker: Justin Hoffman
Chief Technology Officer of AgTechLogic

Title: From Concept to Impact: The Evolution of Moss Robotics through Industry-
University Collaboration

Description: Moss Robotics' journey began with a project focused on autonomous driving technology for tree nurseries, born out of a collaboration between Carnegie Mellon University, Robotics Institute and Hale; Hine Nursery in Tennessee. In this talk, we share the story of how we discovered the real value our solution could offer to growers, and how we refined our ideas through continuous iteration. This process transformed moss robotics from a simple concept into the company it is today. We will cover the steps of our evolution, emphasizing the practical benefits of combining academic research with industry needs to innovate effectively. Additionally, we look ahead to how emerging technologies might further influence our growth and the agricultural industry as a whole, aiming for advancements in farming practices that are both technologically sophisticated and grounded in real-world applications.

Speaker: Di Hu
Founder and CEO
Moss Robotics

Title: AI-Enhanced Computer Vision for Crop Monitoring in Controlled Environment
Agriculture

Description: Controlled environment agriculture (CEA) production remains expensive due to high operation costs. Growers can reduce production costs by nurturing crops with data, however, the data is highly diverse, and growers lack the expertise to analyze this data to derive actionable insights for informed decision-making. In addition, traditional crop monitoring is carried out manually, which makes it unfeasible to collect data daily to get actionable insights for high yields. Recent advancements in sensing and computing technologies, such as AI, computer vision, edge computing, and edge-
cloud integration, have opened opportunities to develop data-driven technologies to enhance decision-making capabilities. Integrating AI and computer vision technologies has emerged as a transformative toolset that can collect real-time plant data at high spatial and temporal resolutions, pivotal in optimizing resource management and maximizing production. The CE Engineering lab delves into cutting-edge computer vision applications within CEA, focusing on various applications, including phenotyping leafy greens, yield estimation, disease monitoring, and plant spacing optimization. This presentation will explore the details of lettuce phenotyping, disease classification, strawberry fruit classification, and yield estimation. We will delve into the technical aspects of these algorithms, including image processing techniques, machine learning models, and data integration strategies. This presentation will showcase state-of-the-art deep learning approaches, including segmentation algorithms, model training, and deep classifiers. Overall, this presentation aims to provide insights into the transformative potential of computer vision in CEA, offering a glimpse into the future of data-driven and sustainable CE production.

Speaker: Azlan Zahid
Assistant Professor,
Department of Biological and Agricultural Engineering
Texas A&M AgriLife Research
Texas A&M University System
Dallas, TX 75252, USA

Panel: 30-minute panel with the above speakers, to allow time for Q&A and discussion.

Moderator

Milt McGiffen

Speakers

Kent D. Kobayashi

Associate Professor, TPSS Dept., Univ. of Hawaii at Manoa

Kathryn Orvis

Professor, Purdue Univ

Di Hu

CEO, moss robotics inc.

Luan Pereira de Oliveira

Justin Hoffman

Chief Technology Officer, AgTechLogic

Azlan Zahid

Texas A

Wednesday September 25, 2024 4:00pm - 6:00pm HST
Coral 3

Colloquium

SUBJECT Technology, Teaching, Growth Chambers and CE

4:14pm HST

Growth Chambers and Controlled Environments 2 (CE 2)

Wednesday September 25, 2024 4:14pm - 5:45pm HST

Coral 2

Carbohydrate Synthesis and Freeze Tolerance of Clonal-type Bermudagrasses as Affected by Mowing Heights During Cold Acclimation and Deacclimation Process - Mingying Xiang
Understanding Photoperiod Effects on Seek and Seedling Quality in Soybean Speed Breeding- Christiane da Silva
Identifying the Optimal Range of pH Management for Hydroponic Leafy Vegetables - Yujin Park
Enhancing Iron Bioavailability in Hydroponic Leafy Greens by Iron Chelators - Asmita Nagila
Effects of Mycorrhiza and Ciochar Interactions on Geraniums - Teal Hendrickson
Exploring Different Nutrient Solution Quantities to Optimize Quantity and Quality in Hydroponic Production - Puja Subedi
The Effect of Climate Change on Plants: A Case Study with Wheat - Kira Webster
How Does Supplementing Dissolved Oxygen Impact Hydroponic Strawberry Production? - Jonathan Ries
Exploring Different EC Levels to Optimize Quantity and Quality in Hydroponic Production - Puja Subedi

Wednesday September 25, 2024 4:14pm - 5:45pm HST
Coral 2

Poster Session, Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

4:15pm HST

CE 2 -Carbohydrate Synthesis and Freeze Tolerance of Clonal-type Bermudagrasses as Affected by Mowing Heights During Cold Acclimation and Deacclimation Process

Wednesday September 25, 2024 4:15pm - 4:25pm HST

Coral 2

Bermudagrass (Cynodon spp.) is a prominent warm-season turfgrass extensively utilized across golf courses, athletic fields, home lawns, and recreational areas due to its excellent heat tolerance, good traffic tolerance, and strong recuperative potential. Despite its strengths, winter survivability in colder climates remains a concern. Research has revealed variations in freeze tolerance across bermudagrass cultivars, yet there's a gap in understanding the underlying physiological mechanisms and the impact of cold acclimation and deacclimation processes. Additionally, the influence of mowing height on carbohydrate synthesis and freeze tolerance has been reported. To address these gaps, a study utilizing turfgrass plugs from different acclimation stages was conducted in a freeze chamber. The objective of this study was to examine freeze tolerance and carbohydrate synthesis in four clonal-type bermudagrass varieties ('Tifway’, ‘Tahoma 31’, ‘Astro’, and ‘TifTuf’) under mowing heights of 0.5” and 1.5” across various cold acclimation and deacclimation stages. The plugs were subjected to soil temperatures ranging from -5°C to -12°C, with survival assessed after three weeks to determine the lethal temperature (LT50) for each condition. Rhizome carbohydrate levels at each stage were determined. The correlation between rhizome carbohydrate level and freeze tolerance was determined. The data from this study is currently being analyzed.

Speakers

Mingying Xiang

Oklahoma State University

Co-authors

Dennis Martin

Oklahoma State University

Lu Zhang

Oklahoma State University

Shuhao Yu

Oklahoma State University

Yanwei Sun

Oklahoma State University

Wednesday September 25, 2024 4:15pm - 4:25pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

4:25pm HST

CE 2 - Understanding Photoperiod Effects on Seed and Seedling Quality in Soybean Speed Breeding

Wednesday September 25, 2024 4:25pm - 4:35pm HST

Coral 2

Soybean is a short-day plant, which means that days must be shorter than a critical value to induce flowering. Manipulating the photoperiod regime is a well-known way to shorten plant cycles in speeding breeding programs. However, the impact of the photoperiod on the quality of the produced seeds is not well understood. Here, we investigate how photoperiod affected the seed and seedling quality in soybean plants, grown in a controlled environment. Soybean (Glycine max) plants (var. S16-14801C and CZ7570LL) were grown in growth chambers with controlled temperature (27 ± 0.5˚C), CO2 (475 ± 15 µmol mol-1), humidity (70 ± 5.0%), and light (300 ± 5 µmol m-2 s-1 at table; 20% blue,10% green, 70% red). One week after germination, seedlings were exposed to different photoperiod regimes: i) 10 h (0 w at 18 h), ii) two weeks at 18 h and then 10 h (2 w at 18 h), iii) four weeks at 18 h and then 10 h (4 w at 18 h); iv) six weeks at 18 h and then 10 h (6 w at 18 h). The plants were grown in the described treatments until the R8 stage (95% brown pods), without changing the light fixture height (industry standard practice). A sample of seeds was harvested and analyzed regarding quality while other samples were placed to germinate in seed germination paper to evaluate germination rate and seedling growth for 10 days. Similar results were found for both varieties; plants of all treatments presented different heights, in which plants at 0 w at 18 h were shorter (50 cm) and 6 w at 18 h taller (180 cm). Treatments did not affect the moisture or weight of 100 seeds. Conversely, germination and seedling survival were 30% lower in seeds from plants 0 w at 18 h than in other treatments. Similar results were found for the root (13% lower in 0 w at 18 h) and shoot length (19% lower in 0 w at 18 h) of seedlings. However, the dry weight of seedlings was similar among treatments. Manipulating the photoperiod can speed up the plant cycle and is a good alternative for speed-breading programs. However, extreme photoperiods and low daily light integral can produce seeds and seedlings with lower quality that can influence the production of plants of the next generation.

Speakers

Cristiane da Silva

Postdoctoral Research Scholar, North Carolina State University

I'm Cristiane, a plant physiologist with experience in plant biochemistry and plant responses to abiotic stress. Currently, I'm a post-doc at NCSU studying the effects of light on plant life cycles to expedite breeding purposes in crop and tree species. When I'm not working, I enjoy... Read More →

Co-authors

Cristian Collado

North Carolina State University

Jan Van Butsele

BASF

Ricardo Hernandez

North Carolina State University

Richard Jack

BASF

Will Bednarz

BASF

Wednesday September 25, 2024 4:25pm - 4:35pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

4:35pm HST

CE 2 - Identifying the Optimal Range of pH Management for Hydroponic Leafy Vegetables

Wednesday September 25, 2024 4:35pm - 4:45pm HST

Coral 2

In hydroponics, the pH of the nutrient solution influences the solubility and availability of essential nutrients. The optimal pH for plant nutrient uptake in many crop species is around 6.0. However, the impacts of precise pH management on plant nutrient uptake, crop yield, and the optimal pH range remain less clear. In this study, we investigated the effects of pH management range on plant nutrient uptake and the growth of hydroponic leafy vegetables. Within an indoor vertical farm, we grew lettuce (Lactuca sativa) 'Rex,' kale (Brassica oleracea var. sabellica) 'Red Russian,' and arugula (Eruca sativa) 'Astro' using deep water culture hydroponics at the air temperature of 22 °C under a photosynthetic photon flux density of 200 μmol∙m−2∙s−1 with a 24-h photoperiod. The experiment included six pH treatments: pH 6, 6±0.5, 6±1.0, 6±1.5, 6±2.0, and without pH control. Compared to managing pH at 6, maintaining pH within 6±1.0 had generally similar impacts on leaf number, leaf area, SPAD index, shoot and root fresh mass, and shoot and root dry mass in all three crops. However, when compared to managing pH at 6, maintaining pH at 6±1.5 or greater reduced leaf area (by 32-47% in lettuce, by 30-41% in kale, or by 56-65% in arugula) and shoot fresh mass (by 33-54% in lettuce, by 37-45% in kale, or by 48-64% in arugula). Furthermore, in comparison to managing pH at 6, maintaining pH at 6±1.5 or greater also decreased leaf number in lettuce by 3-5 leaves and in arugula by 13-15 leaves but increased the root fresh mass of lettuce by 26-43%. Our results suggest that maintaining pH within 6±1.0 can be effective in promoting optimal nutrient uptake and overall plant development in the context of hydroponic cultivation.

Speakers

Yujin Park

Arizona State University

Co-authors

Matthew Easter

Arizona State University

Zhihao Chen

Arizona State University

Wednesday September 25, 2024 4:35pm - 4:45pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

4:45pm HST

CE 2 - Enhancing Iron Bioavailability in Hydroponic Leafy Greens by Iron Chelators

Wednesday September 25, 2024 4:45pm - 4:55pm HST

Coral 2

Iron is an essential micronutrient for the growth and development of both plants and humans, as it plays vital roles in processes such as protein synthesis, respiration and DNA replication. Leafy greens, vital dietary sources of iron, can be cultivated with increased bioavailable iron through hydroponics by customizing nutrient solutions. Conventionally, iron chelates like EDTA and DTPA, are used in hydroponics, but challenges persist in iron acquisition due to their pH dependency as well as quick oxidation to ferric ion which is harder to uptake by plants. Good sources of chelates that respond well to high pH values, like EDDHA, are often more expensive. Studies suggest that iron complexed with humic substances exhibits higher efficiency, though confirmation in large-scale hydroponic systems is still needed. Fulvic acids are water-soluble humic substances with lower molecular weights that hold promise as alternatives or supplements to synthetic chelates, enhancing iron uptake and stress tolerance. Hydroponic systems, such as Deep-Water Culture (DWC) or Nutrient Film Technique (NFT), impact plant growth and nutrient uptake differently based on temperature, EC, and pH. This research compared the effects of various iron chelators on lettuce and kale cultivation in DWC and NFT systems. Results indicate significant yield loss in iron-deficient kale, while iron-chelated solutions enhanced yields. The addition of fulvic acid to EDTA-chelated solutions notably improved kale yield in DWC compared to no iron and EDTA-only solutions. Leafy greens showed higher chlorophyll fluorescence (Fv/Fm ratio) and chlorophyll content in DWC compared to NFT. The results showed species-specific and system-specific responses. Notably, iron-chelated plants exhibit higher iron content correlating with increased shoot weight and chlorophyll content. The effect of fulvic acids and synthetic chelates might be synergistic, with both providing different advantages that can be complementary in hydroponic solutions. This study highlights the importance of iron management in hydroponics and the way forward for iron fortification techniques.

Speakers

ASMITA NAGILA

Graduate Research Assistant, Texas A&M university

Co-authors

Daniel Leskovar

Texas A

Seunghyun Choi

Texas A

Wednesday September 25, 2024 4:45pm - 4:55pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

4:55pm HST

CE 2 - Effects of Mycorrhiza and Biochar Interactions on Geraniums

Wednesday September 25, 2024 4:55pm - 5:05pm HST

Coral 2

Biochar has long been proposed to be a substitute for peat in soilless mixes for greenhouse growing. Low levels of biochar have been shown to increase disease resistance, increase nutrient supply and uptake, and immobilize phytotoxic substances. Due to its high porosity and pH, biochar has the potential to provide an ideal habitat for mycorrhizal fungi to partner with plant roots. This study examined how various mycorrhiza sources interacted with different biochar rates to effect geraniums (Pelargonium x hortorum L. ‘Maverick Red’). Four different mycorrhizal sources were used in addition to a control containing no mycorrhiza: two commercial sources, MycoBloom and BioAg Vam-Endo, spores extracted from agricultural soils, and spores extracted from prairie soil, with four biochar rates implemented: 0, 15, 30, and 45%. Media with biochar incorporated remained saturated for longer periods after irrigation than pots filled with straight BM-7 peat-media. Prairie soil combined with 15% biochar-BM7 media formed buds and began to flower before all other treatments. Results suggest that biochar and mycorrhiza may pair well to improve potted plant growing.

Speakers

Teal Hendrickson

Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Gail Wilson

Oklahoma State University

Wednesday September 25, 2024 4:55pm - 5:05pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

5:05pm HST

CE 2 - Exploring Different Nutrient Solution Quantities to Optimize Quantity and Quality in Hydroponic Production

Wednesday September 25, 2024 5:05pm - 5:15pm HST

Coral 2

Nutrient solutions play a crucial role in determining crop yield and quality, with optimized quantities offering sustainability benefits. However, there is a lack of comprehensive research regarding the optimal nutrient application quantity for various leafy green vegetables in recirculating hydroponic cultivation. To address this research gap, we proposed a project on different nutrient application quantities using the nutrient film technique (NFT) hydroponic system in a greenhouse with three replications during the fall (air temp: 24.22°C, RH: 31.2%), winter (air temp: 15.5 °C, RH: 73.3%) and early spring (air temp: 13.7 °C, RH: 72.4% ). The project focused on exploring different nutrient solution quantities of Low (76 liters), Medium (114 liters), and High (151 liters) nutrient regimens for six different leafy green vegetable species and cultivars common in Kansas including red butter lettuce (Lectuca sativa), green butter lettuce (Lectuca sativa), arugula (Eruca sativa), kale (Brassica oleracea), red malabar spinach (Basella alba), and basil (Ocimum basilicum). Our results showed that green butter lettuce and basil remained unaffected by the treatments throughout the study. Additionally, plant height, leaf count, and SPAD value for all species remained consistent across treatments and seasons. However, during the fall, the shoot fresh weight of red butter lettuce and kale increased by 7.11% and 21.1%, respectively, in the high-nutrient regimen. Moreover, the dry shoot weight of kale increased by 18.7% in the high-nutrient regimen, while the dry shoot weight of the red malabar spinach increased by 10.3% in the low-nutrient regimen. In contrast, during winter, the shoot fresh weight of red butter lettuce increased by 18.9% and 25.0%, respectively, in medium nutrient regimens compared to low and high nutrient regimens. Similarly, the shoot fresh weight of red malabar spinach increased by 15.3% and 25.0%, respectively, in low-nutrient regimens compared to medium and high-nutrient regimens. During early spring, the shoot fresh weight of red butter lettuce increased by 17.9-18.0% and that of arugula increased by 17.8% in the high-nutrient regimen, compared to low and medium nutrient regimens. In summary, the high-nutrient regimen benefited red butter lettuce and kale in fall and arugula in early spring. Conversely, during winter, the medium nutrient regimen benefited red butter lettuce, while the low nutrient regimen benefited red malabar spinach. The results from this experiment identified the optimal nutrient application quantity which helps to reduce nutrient waste for vital leafy vegetables in Kansas for different seasons and offers valuable production guidelines for local growers.

Speakers

Puja Subedi

Kansas State University

I am a graduate research assistant working at the Kansas University Olathe, 22201 W Innovation Dr, Olathe, KS 66061. My major is urban food system under the department of horticulture and natural resources. Currently, I am working in the hydroponics research project.

Co-authors

Teng Yang

Kansas State University

Wednesday September 25, 2024 5:05pm - 5:15pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

5:15pm HST

CE 2 - The Effect of Climate Change on Plants: A Case Study with Wheat

Wednesday September 25, 2024 5:15pm - 5:25pm HST

Coral 2

Anthropogenic climate change (ACC) will have considerable effects on plants, though the extent to which these effects are positive or negative has been controversial. For this poster, a fully factorial experiment combining water and temperature over broad ranges (10-90% soil water content under 16°C-40°C) was carried out to address three shortcomings that might help explain the contrasting effects of climate change on plants: testing only one climate variable (e.g., only water or only temperature), failure to account for nonlinear responses to climatic variables, and studying a limited number of response variables. The experiment utilized wheat as the model species and found that most dependent variables related to grain production showed the highest performance under 23-33°C and low water (

Speakers

Kira Webster

University of Hawaii at Manoa

Wednesday September 25, 2024 5:15pm - 5:25pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

5:25pm HST

CE 2 - How Does Supplementing Dissolved Oxygen Impact Hydroponic Strawberry Production?

Wednesday September 25, 2024 5:25pm - 5:35pm HST

Coral 2

Oxygen is crucial for the growth and nutrient uptake of plant roots, especially in crops like strawberries that demand high levels of oxygen in their root zones. However, in hydroponic systems, the nutrient solution is often inadequately oxygenated. In this study, we examined the effects of supplementing dissolved oxygen (DO) into the nutrient solution on the growth of strawberry plants. Inside an indoor vertical farm, bare-root plants of strawberry ‘Albion’ and ‘Eversweet’ were grown using deep water culture hydroponics under a controlled environment of 23 °C air temperature and an 18-h photoperiod, with an extended photosynthetic photon flux density of 350 µmol∙m –2 ∙s –1 . The DO concentration of the nutrient solution was maintained at control levels (no adjustment) or supplemented using an air pump or an oxygen concentrator. The average DO concentrations in the control condition was 70%, while supplementing the nutrient solution with an air pump or an oxygen concentrator increased the average DO concentration to 85% and 100%, respectively. Supplementing with DO had minimal to no effect on the days to root of strawberry bare root plants in both cultivars. Four weeks after the DO treatments, root length, crown diameter, leaf area, and fresh mass of shoot and root were also similar in both cultivars regardless of DO concentration. The effects of supplementing DO on flowering and fruit production will also be presented.

Speakers

Jonathan Ries

Arizona State University

Co-authors

Yujin Park

Arizona State University

Wednesday September 25, 2024 5:25pm - 5:35pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

5:35pm HST

CE 2 - Exploring Different EC Levels to Optimize Quantity and Quality in Hydroponic Production

Wednesday September 25, 2024 5:35pm - 5:45pm HST

Coral 2

Efficient nutrient management is the key to successful hydroponic production. However, there is a lack of comprehensive research regarding the optimal electrical conductivity (EC) levels for various leafy green vegetables in recirculating hydroponic cultivation. To address this research gap, we experimented with different EC levels using the nutrient film technique (NFT) hydroponic system in a greenhouse with three replications during the fall (air temp: 24.22°C, RH: 31.2%) winter (air temp: 15.5 °C, RH: 73.3%) and early spring (air temp: 13.7 °C, RH: 72.4%). The experiment was conducted using three different EC levels (1.2, 1.8, and 2.4 mS/cm) for six different leafy green vegetables kale (Brassica oleracea) ‘Winter bor F1’ and ‘Toscano’, swiss chard (Beta vulgaris), basil (Ocimum basilicum) ‘Prospera® Compact DMR (PL4)’ and ‘large leaf’ and red malabar spinach (Basella alba). Our results showed that, during the fall, the shoot fresh weight of the ‘Winter bor F1’ increased by 13.1 % in EC 2.4 compared to EC 1.2 and that of Swiss chard increased by 8.3-20.6% in EC 2.4 compared to EC 1.2 and 1.8 while that of ‘Prospera® Compact DMR (PL4)’ basil increased by 13.1-13.9 % in EC 1.8 compared to EC 1.2 and 2.4. In contrast during the winter, the shoot fresh weight of ‘Toscano’ kale, ‘Winter bor F1’ kale, and ‘large leaf’ basil increased by 11.2-17.8%, 18.9-20.8%, and 13.2-14.7%, respectively in EC 2.4 compared to EC 1.2 and 1.8, while that of ‘Prospera® Compact DMR (PL4)’ basil increased by 19.2 % in EC 1.2 compared to the EC 2.4. However, during the early spring, only the shoot fresh weight of ‘Winter bor F1’ kale in EC 1.8 was increased by 10.0 % compared to EC 1.2, while the plant height and fresh shoot weight of large leaf basil was increased slightly by 3.1-5.6% in EC 2.4 compared to EC 1.2. In summary, this experience suggested that ’Winter bor F1’ kale performed best in EC 2.4 during the fall and winter seasons but grew best in EC 1.8 during the early spring. In addition, the 2.4 mS/cm proved the optimal EC level for Swiss chard during the fall, ‘Toscano’ kale during the winter, and ‘large leaf’ basil during the spring. The results from this experiment identify optimal EC levels of vital leafy vegetables in Kansas for different seasons, aiding Kansas growers in reducing nutrient waste and enhancing leafy vegetable production.

Speakers

Puja Subedi

Kansas State University

Co-authors

Teng Yang

Kansas State University

Wednesday September 25, 2024 5:35pm - 5:45pm HST
Coral 2

Poster presentation (individual talk), Growth Chambers and Controlled Environments 2

SUBJECT Growth Chambers and CE

7:59am HST

Growth Chambers and Controlled Environments 4 (CE 4)

Thursday September 26, 2024 7:59am - 9:45am HST

Coral 1

Night Light Pollution Delays Flowering in Soybean and Cannabis - Madigan Eckels
Pre-breeding Leafy Green Watercress (Nasturtium officinale; Brassicaceae) In an Indoor Vertical Farm: A Discovery Trial - Yufei Qian
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila
Planting Density on the Growth and Production of Select Fruiting Crops in Aquaponic Systems - Teal Hendrickson
Global Sensitivity Analysis and Validation of the Modified Energy Cascade Crop Model for Controlled Environment Agriculture - Donald Coon
Planting Density and the Growth of Kale and Cilantro in Year-round Aquaponics - Teal Hendrickson
The Physiological Responses of Citrus Tree Roots to Soil Acidification - Duplicate Sambani
Towards Sustainable Controlled Environment Agriculture Systems: Developing An Intelligent Decision-Making Tool For Improved Resource Use Efficiency - Eshwar Ravishankar

Speakers

Madigan Eckels

Utah State University

Thursday September 26, 2024 7:59am - 9:45am HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:00am HST

CE 4 - Night Light Pollution Delays Flowering in Soybean and Cannabis

Thursday September 26, 2024 8:00am - 8:15am HST

Coral 1

As urban centers encroach on agricultural land, it is increasingly important to study the effects of light pollution on sensitive short day flowering crops such as Glycine max (soybean) and Cannabis sativa. Common responses to light pollution include delayed flower initiation and development, and Cannabis growers additionally speculate a myriad of other detriments as a result of light pollution. We conducted a series of studies with three soybean and ten Cannabis cultivars to elucidate responses to light pollution. Plant were grown under full-night light pollution ranging from 0 to 150 nanomols m-2 s-1 of cool white light or 0 to 40 nmols m-2 s-1 of red light at 660 nm. We found that continuous light pollution as low as 10 nmol m-2 s-1 from cool white LEDs delayed inflorescence initiation and development of the most sensitive Cannabis cultivars, while red light pollution as low as 5 nmol m-2 s-1 caused similar effects. In cultivars that did not experience a delay in inflorescence initiation, other plant characteristics including height and inflorescence development rate were negatively impacted. In soybean, flower delay in response to light pollution varied by cultivar but was reduced or absent in more modern lines, indicating that breeding may have selected against light sensitivity. Future growers must consider tolerance to light pollution during cultivar selection in order to avoid the detrimental impacts to short day crops.

Speakers

Madigan Eckels

Utah State University

Co-authors

Bruce Bugbee

Utah State University

Mitch Westmoreland

Utah State University

Paul Kusuma

Utah State University

Thursday September 26, 2024 8:00am - 8:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:15am HST

CE 4 - Pre-breeding Leafy Green Watercress (Nasturtium officinale; Brassicaceae) In an Indoor Vertical Farm: A Discovery Trial

Thursday September 26, 2024 8:15am - 8:30am HST

Coral 1

Our research is to define and develop pre-breeding resources as foundational knowledge to underpin breeding of a specialty leafy green crop watercress (Nasturtium officinale; Brassicaceae). This is being achieved by screening a unique, worldwide collection of watercress population to discover and to enhance nutritional traits for health, morphology, and sensory of the indoor controlled environment agriculture (CEA) market. Watercress is a perennial semi-aquatic leafy green vegetable in the Brassicaceae family and is an understudied specialty crop that has important human health benefits. The most abundant secondary metabolite glucosinolate (GLS) in watercress is gluconasturiin, an aromatic GLS, which hydrolyses and releases phenethyl-isothiocyanates (PEITC). PETIC, specifically from watercress, has been proven to have chemo-preventative potentials. Wild germplasm collection harbours natural variations and useful trait discovery opportunities for introgression of novel traits into the existing gene pool. There is limited interdisciplinary research on crop nutrition and breeding for the CEA settings. We found that watercress is well-suited to indoor hydroponic growing. We established the first indoor vertical farm (VF), a controlled growth chamber in a shipping container, at University of California, Davis. Light quality and quantity both serve important roles in watercress growth and development, and a fully controllable vertical farm allows testing a suite of traits of interests with altered LED light regimes. Results showed that VF grown wild watercress possessed significant genotypic differences across treatments, indicating an abundant natural diversity. Altering red to blue LED light ratio and duration may further enhance the anti-cancer GLS compounds as well as nutritional quality profile of this leafy crop.

Speakers

Yufei Qian

PhD candidate, University of California, Davis

Co-authors

Daniel Klibenstein

University of California, Davis

Ella Katz

University of California, Davis

Gail Taylor

University of California, Davis

Thursday September 26, 2024 8:15am - 8:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:30am HST

CE 4 - Planting Density on the Growth and Production of Select Fruiting Crops in Aquaponic Systems

Thursday September 26, 2024 8:30am - 8:45am HST

Coral 1

Traditionally, aquaponic systems are used to produce leafy greens and herbs, while fruits and fruiting vegetables have been considered more difficult to grow due to additional nutrient requirements. When nutrients are not a limiting factor, the possibility of producing more fruit per square foot by increasing planting density is tempting as global populations increase and agricultural land area decreases. This study examined the effects of two different densities on banana peppers (Capsicum annuum L. var ‘Goddess F1’) and pole beans (Phaseolus vulgaris L. ‘Seychelles OG’) in a 20 sq ft grow bed. High densities consisted of 14 and 22 pepper and bean plants respectively, while low densities were 7 and 11 pepper and bean plants. Higher densities of peppers and beans produced more fruits than lower densities, while plant dry biomass of higher densities appeared to be lower than higher densities. Results suggest that higher planting densities of peppers and beans may increase harvestable fruit.

Speakers

Teal Hendrickson

Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Mitchell Sommer

Symbiotic Aquaponic

Thursday September 26, 2024 8:30am - 8:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:45am HST

CE 4 - Planting Density and the Growth of Kale and Cilantro in Year-round Aquaponics

Thursday September 26, 2024 8:45am - 9:00am HST

Coral 1

Use of aquaponic systems has the potential to provide sustainable food production in a variety of environments year-round. Unfortunately, little is known about the limitations of aquaponics regarding planting density in a grow bed and year-round growing outside of tropical climates. This study evaluated two different planting densities of kale (Brassica oleracea var. acephala L. ‘Winterbor’) and cilantro (Coriandrum sativum L. ‘Cruiser’) in a 20 sq ft grow bed in a hoophouse grown during winter and early spring in Stillwater, OK, using bluegill (Lepomis macrochirus L.) as the fish species. High planting densities comprised of 54 kale plants and 68 cilantro plants. Low densities contained 36 kale plants and 48 cilantro plants. High planting density reduced fresh weight and chlorophyll content in kale, and chlorophyll content in cilantro. Additionally, total nitrogen content decreased at higher densities of kale while sulfur content increased. Cold weather mitigation was utilized in the form of a secondary plastic covering, extra light sources, and in-line heaters. Results suggest that higher planting density may be feasible for some leafy green and herb species while being detrimental to others and that year-round growing may be possible with the addition of inline water heaters.

Speakers

Teal Hendrickson

Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Mitchell Sommer

Symbiotic Aquaponic

Thursday September 26, 2024 8:45am - 9:00am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:00am HST

CE 4 - The Physiological Responses of Citrus Tree Roots to Soil Acidification

Thursday September 26, 2024 9:00am - 9:15am HST

Coral 1

Citrus tree roots are vital in nutrient uptake, water absorption, and overall plant health. Soil pH alters the availability and mobility of essential nutrients in the soil, thus influencing root physiological processes; like most plants, citrus trees are particularly vulnerable to changes in soil pH levels. The root apoplast is the plant component that first encounters adverse soil chemical conditions; hence, the conditions in the root apoplast determine a plant's response. This study aims to investigate the physiological responses of citrus tree roots to soil acidification, focusing on the impact of varying soil pH on root morphology, nutrient uptake, and overall root health. A controlled three-month greenhouse study was conducted at the Citrus Research and Education Center (CREC), hypothesizing that soil acidification will alter apoplast and phloem pH, reducing CLas population and root damage. This study was conducted utilizing citrus trees subjected to different soil pH levels. Forty trees were used and divided into four groups by pH treatment. These trees were irrigated thrice a week with pH treatments: 5.5, 6.5, 7.5, and 8.5. Soil acidity and alkalinity were routinely monitored with pH probe sticks. Once soil pH stabilized, feeder root samples were taken for apoplastic and phloem pH experiments. The pH-sensitive fluorescent stains were used for microscopy and vacuum infiltration to collect apoplastic fluids. Parameters such as root length, root surface area, and root diameter were measured to assess the morphological changes in citrus tree roots under different pH treatments. The concentration of essential macro- and micronutrients from the soil, plant tissue, and leachates was also analyzed weekly to evaluate nutrient uptake efficiency. Preliminary results indicate that soil acidification significantly improves fruit yield and feeder root density. By ascribing the specific mechanisms underlying root responses, this research provides valuable insights into the adaptive capabilities of citrus trees. It informs future practices to preserve the health and productivity of citrus groves.

Speakers

Duplicate Sambani

PhD Student, University of Florida

Co-authors

Davie Kadyampakeni

University of Florida

Thursday September 26, 2024 9:00am - 9:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:15am HST

CE 4 - Towards Sustainable Controlled Environment Agriculture Systems: Developing An Intelligent Decision-Making Tool For Impro

Thursday September 26, 2024 9:15am - 9:30am HST

Coral 1

Controlled Environment Agriculture (CEA) systems significantly enhance crop yields per unit area in comparison to traditional open-field farming methods. Moreover, they contribute to reduced water consumption and offer extended and more predictable growing seasons. While CEA systems show promise in meeting urban vegetable demand, the question remains what the required inputs are (water, fertilizer, energy, labor) for different systems (vertical farm, greenhouses) in different climate locations. In this work, an easy-to-use transient energy model that simulates the internal microclimate of CEA systems is developed. The microclimate will include changes in temperature, humidity, water, nutrient, and carbon dioxide while also computing the energy costs associated with conditioning the space and electricity. This model will also accurately map the leaf temperature and hence compute the transpiration water loss accounting for the spectra of different artificial light sources. The energy model will be linked to a functional crop growth model that can simulate the yield of the plant over multiple growth cycles and quantify water and nutrient uptake. The potential of the developed model is demonstrated by performing simulations of year-around greenhouse operation within the U.S. Two climates categorized into hot, and cold based on annual temperature are selected for the simulation of tomato production. Results indicate that supplemental lighting energy requirement ranged between 128-160 kWh/m2-year across the selected climate zones to achieve target yield in a given duration. Overall energy consumption ranges from 200 - 400 kWh/m2-year. Overall, the supplemental lighting requirement makes upto 75 percent of the total required DLI and provides comparable improvements in biomass compared to yield in greenhouses without supplemental lighting. Finally, the model indicates that upto 90 percent of total supplemental lighting requirements require light intensities in the combination of 250 and 500 µmoles m-2 s-1 to satisfy the additional DLI requirement. However, a higher lighting intensity of 1000 µmoles m-2 s-1 is required sporadically at night during winter between October – March in the northern latitudes. Overall, this model integrates energy, temperature, nutrition, and crop yield considerations for various crops and acts as a useful predictive tool for assessing operational costs based on target yield and duration of growth for greenhouses operating in any given climate.

Speakers

Eshwar Ravishankar

Assistant Professor, Cal Poly Pomona

Co-authors

Lahari Sandepudi

Cal Poly Pomona

Ricardo Hernandez

North Carolina State University

Thursday September 26, 2024 9:15am - 9:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:30am HST

CE 4 - Global Sensitivity Analysis and Validation of the Modified Energy Cascade Crop Model for Controlled Environment Agricult

Thursday September 26, 2024 9:30am - 9:45am HST

Coral 1

The Modified Energy Cascade (MEC) crop model was originally developed to predict the edible biomass production of bioregenerative life support systems (BLSS) along with BLSS consumption and production of O2 and CO2. Three distinct MEC versions support this original goal and controlled environment agriculture (CEA) on Earth. Cavazzoni built the first MEC for predicting crop growth, transpiration, and productivity of BLSS. Boscheri et al. and Amitrano et al. each developed versions building off Cavazzoni's work. While each of these model versions builds off each other, differences in methodology and assumptions of plant physiology impact the outputs of the model, necessitating a comparison between versions. To describe the effects of input variability and model structure on the outputs of the MEC versions before further development for BLSS and CEA production facilities, four research questions were chosen to guide this evaluation. 1) How much variation in transpiration and yield predictions can be attributed to the model version? 2) How are input variations propagated through the cascading nature of the models? 3) Which model components are highly sensitive or uncertain to which environmental conditions? 4) How well does each model version predict the outcome of lettuce yield and transpiration outcomes of data sets independent from model development? To answer the first three questions, a series of global sensitivity and uncertainty analyses were performed. They revealed that 1) for daily transpiration rate and edible biomass model version alone can explain between 69% and 82% with Amitranos representing the lowest values and Boscheris the highest typically. 2) Even in sequences of identical equations, where each subsequent calculation is identical, variability is gradually reduced with final output variations between 40% - 55% that can be attributed to the prior upstream differences. 3) The Cavazzoni and Boscheri edible yield predictions are highly sensitive to photosynthetic photon flux density (PPFD) and CO2 across calculations while Amitrano’s is more responsive to photoperiod rather than PPFD. 95% of Boscheris transpiration output is driven by relative humidity while the other two utilize a combination of that and photoperiod. Lastly, these models and their performance were evaluated using environmental and yield data from an indoor vertical farming facility and growth chamber experiments. Together these analyses provide the information necessary to continue the development of the MEC for the prediction of resource flows and yield of CEA and BLSS supporting the optimization of electricity usage and circularity processes within closed-loop agriculture.

Speakers

Donald Coon

University of Florida

Co-authors

Ana Martin Ryals

University of Florida

Chiara Amitrano

University of Naple

Gerardo Nunez

University of Florida

Melanie Correll

University of Florida

Rafael Carpena

University of Florida

Ying Zhang

University of Florida

Ziynet Boz

University of Florida

Thursday September 26, 2024 9:30am - 9:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:59am HST

Growth Chambers and Controlled Environments 5 (CE 5)

Thursday September 26, 2024 9:59am - 12:00pm HST

South Pacific 3

Quality Analysis of Bitter Acids in Hops (Humulus lupulus L.) from a Controlled Environment Versus Field Production System - Katie Stenmark
The Affect of High pH on Hydroponic Lettuce in a Controlled Environment - Alexander Speck
Drought Stress Responses of North American Native Bog Birch and Sweetgale in a Sensor-automated System - Jessica Hutchinson
Effects of Plant Growth Promoting Rhizobacteria on Yield of Amaranth viridis Linn. Grown in a Growth Chamber and Greenhouse - Zachary Williams
Shade-Avoidance Responses of Kale and Lettuce Elicited by Far-Red Light Can Persist Under High-Light Intensity - Jiyong Shin
Does Intermittent and Continuous Nutrient Flow Affect the Growth and Phytochemicals of Culinary Herbs in NFT Hydroponics - Abishkar Regmi
Adjusting Supplemental LED Light Intensities Based on Real-time Chlorophyll Fluorescence Measurements in a Greenhouse - Suyun Nam
Interactions of Far-Red Photons with Orange Photons or Red Photons: Photosynthetic Response, Morphology and Fruit Yield - Seonghwan Kang

Speakers

katie stenmark

OKLAHOMA STATE UNIVERSITY

Crop Science PhD Student Department of Horticulture and Landscape Architecture Oklahoma State University

Thursday September 26, 2024 9:59am - 12:00pm HST
South Pacific 3

Oral Sessions, Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

10:00am HST

CE 5 - Quality Analysis of Bitter Acids in Hops (Humulus lupulus L.) from a Controlled Environment Versus Field Production Syst

Thursday September 26, 2024 10:00am - 10:15am HST

South Pacific 3

Hop plants are produced for harvest of mature hop cones that are utilized in the medicinal, agricultural, cosmetic and craft beer industries. Hop plants are vigorously climbing perennials that require shorter than 15-hour days for flowering induction, and a trellis structure (3-6m annual height) for seasonal support. In the United States, the majority of hops are grown in field production systems in the Pacific Northwest where summer day lengths are long. The demand for hops has increased due to a boom in the craft beer industry which has led growers in southern states to seek alternative methods for producing hops outside of their traditional commercial growing region. Hop performance in greenhouse systems has not been evaluated in Oklahoma before, but controlled environments offer an alternative for hop producers in the south to limit pests, reduce contact with Downy Mildew (Pseudoperonospora humuli), and harvest multiple crops per year. Four cultivars of hops (‘Cascade’, ‘Comet’, ‘Newport’, ‘Tahoma’) were grown on a 3m trellis using a Dutch bucket hydroponic system with one rhizome per bucket spaced 0.5m apart without supplemental lighting in the USDA research greenhouses at Oklahoma State University. Four identical cultivars of hops were grown in a field system using a V-style trellis (5m height) at the Cimarron Valley Research Station in Perkins, OK. Mature hop cones were hand harvested at 80% moisture and dried at ambient temperature to 8-10% moisture. Hops were stored for up to six months frozen under nitrogen in vacuum sealed bags until analysis was performed. Hop bitter acids (α-acids and β-acids) were extracted using a 0.1% formic acid solvent, and hop quality was determined by HPLC. Bitter acids of greenhouse hops were determined to be highest in cultivars ‘Comet’ (α- 2.12%, β- 0.73%), ‘Cascade’ (α- 2.00%, β- 1.04%), and ‘Tahoma’ (α- 1.92%, β- 1.23%), where ‘Newport’ had a notably lower α and β-acid content (α- 0.71%, β- 0.81%). Bitter acid quality in field hops were comparable to hops produced in the greenhouse (‘Cascade’ α- 2.99%, β- 1.77%; ‘Newport’ α- 2.95%, β- 1.56%; ‘Tahoma’ α- 1.42%, β- 1.56%; ‘Comet’ α- 1.95%, β- 0.71%). With the information from this research, local greenhouse growers will be able to determine if hops are a viable option for their region.

Speakers

katie stenmark

OKLAHOMA STATE UNIVERSITY

Crop Science PhD Student Department of Horticulture and Landscape Architecture Oklahoma State University

Co-authors

Bruce Dunn

OKLAHOMA STATE UNIVERSITY

Charles Fontanier

OKLAHOMA STATE UNIVERSITY

Victoria Hughes

OKLAHOMA STATE UNIVERSITY

Thursday September 26, 2024 10:00am - 10:15am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

10:15am HST

CE 5 - The Affect of High pH on Hydroponic Lettuce in a Controlled Environment

Thursday September 26, 2024 10:15am - 10:30am HST

South Pacific 3

In North Dakota, indoor-grown lettuce faces water pH levels higher than the ideal 5.5 to 6.5 range, with Fargo's water averaging a pH of 9.2 from 2018 to 2022. Addressing the gap in research on high pH's impact on lettuce, this study, running from 2023 to 2024, explored the effects of pH levels on the yield of lettuce grown in deep water culture (DWC) hydroponic systems. We tested three lettuce varieties (Casey, Gladius, and Tendita) under four pH conditions (6.3, 7.0, 8.3, and an unbuffered level), with each setup replicated four times. Th initial growth was in rock wool cubes under a clear dome for a month before transferring to DWC for another month. The results indicated significant differences in yield and size across pH levels and varieties. Gladius yielded the highest at pH 6.3 (86.0 g/plant), while Casey showed the lowest yield at pH 7.0 (9.6 g/plant). Gladius also achieved the largest diameter (25.1 cm) at pH 6.3, contrasting with Casey's smallest at 7.0 pH (10.2 cm). Notably, high pH (8.3) still produced reasonable yields and sizes, especially with the Gladius variety, highlighting the potential for selecting suitable varieties to mitigate adverse pH effects. This study underscores the importance of variety selection in hydroponic systems with non-ideal water pH, providing crucial insights for optimizing indoor lettuce production.

Speakers

Alexander Speck

North Dakota State University

Co-authors

Xiaoyu Feng

North Dakota State University

Xinhua Jia

North Dakota State University

Thursday September 26, 2024 10:15am - 10:30am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

10:30am HST

CE 5 - Drought Stress Responses of North American Native Bog Birch and Sweetgale in a Sensor-automated System

Thursday September 26, 2024 10:30am - 10:45am HST

South Pacific 3

Climate change in the Northern United States is causing less consistent rain events that pressure horticulturists to mitigate the negative impacts of drought stress in ornamental plants. Selecting ornamental native plants that can adapt to predicted changes in climate is a way to preserve and strengthen landscape biodiversity and resilience. Bog birch (Betula pumila) and sweetgale (Myrica gale) are native, colony-forming shrubs indigenous to bogs across the Northern regions of North America with aesthetic features that merit their introduction as ornamental plants. The successful introduction of wetland plants into the nursery industry depends upon their tolerances to variation in water availability typical of managed landscapes. Our 8-week study assessed physiological responses to gradual declines in substrate volumetric water content (VWC) for both shrubs, as water stress intolerance may be a constraint in horticultural landscapes. To model a severe water deficit, we built an automated irrigation system using Arduino microcontrollers connected to soil moisture sensors and solenoid valves that allowed us to track and control VWC. Control plants were maintained at 40% throughout the 8-week period, while drought was simulated by decreasing VWC by 5% each week. Water potential, stomatal conductance, and rate of leaf photosynthesis declined in the plants experiencing drought, with symptoms of leaf dieback and yellowing. In contrast, plants held at 40% VWC maintained physiological functions and had minimal aesthetic decline. By week 8, droughted bog birch and sweetgale reduced their leaf dry masses by 20% and 28%, respectively, relative to control plants. Plants held at 5% VWC had lower stomatal conductance and photosynthetic rates compared to those held at 40%, with sweet gale showing a steeper decline compared to bog birch. During the experiment, stomatal conductance of drought-stressed bog birch and sweetgale decreased by 93% and 77% respectively, and increased for control plants. Similarly, bog birch and sweetgale experienced photosynthetic declines, with respective average decreases of 68% and 62%. At the end of the experiment bog birch maintained a higher leaf retention after severe drought. Most plants of both species retained some living leaf tissue under severe drought. Despite their natural habitats in waterlogged areas, bog birch and sweetgale have potential as drought tolerant, native ornamental shrubs for gardens and landscapes.

Speakers

Jessica Hutchinson

University of Maine

Co-authors

Bryan Peterson

University of Maine

Stephanie Burnett

University of Maine

Thursday September 26, 2024 10:30am - 10:45am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

10:45am HST

CE 5 - Effects of Plant Growth Promoting Rhizobacteria on Yield of Amaranth viridis Linn. Grown in a Growth Chamber and Greenhouse

Thursday September 26, 2024 10:45am - 11:00am HST

South Pacific 3

Amaranth viridis Linn. (amaranth), commonly referred to as Callaloo, is highly nutritious, drought tolerant, and require few inputs to grow. Amaranth is also known to have pharmacological properties. However, this crop is susceptible to pest damage, which hinders the crops growth, development, and marketable yield. Plant growth promoting rhizobacteria (PGPR) are naturally occurring soil microorganisms that live in the rhizosphere, aggressively colonize plant roots, and provide many benefits to plants. PGPR can promote plant growth, improve plant tolerance to biotic and abiotic stresses, increase nutrient and water uptake, and cause induced systematic resistance. This study was conducted to investigated the application of PGPR on yield and development of amaranth grown in a growth chamber and greenhouse. The study was conducted at the University of Maryland Eastern Shore Agricultural Experiment Station in a complete randomized design with four treatments (T1: Control, T2: Strand 209 (single strand), T3: Blend 5 (double strand), T4: Blend 8 (triple strand)), and six replications in the growth chamber study and nine replications in the greenhouse studies. One growth chamber study (duration for 5 weeks) and three greenhouse studies (summer 2022, fall 2022, and summer 2023) were conducted for ten weeks. Amaranth shoots grown in the greenhouse were harvested biweekly, and fresh weight and dry weight were measured. In both PGPR studies, height data and chlorophyll content were collected weekly, and fresh and dry weight of the whole plant (shoots and roots) were collected at the final harvest. Blend 5 was shown to significantly increase shoot growth when compared to the other treatments in the growth chamber study. In the 2022 summer greenhouse, Strand 209 and Blend 8 significantly increased root biomass, while Blend 5 significantly increased fresh weight of the whole plant. In the 2023 summer study, Strand 209 was significantly higher in average shoot dry weight and whole plant fresh weight when compared to the other treatments. The results of both studies showed that the application of PGPR increased amaranth growth and development. Future studies will evaluate the effects of the PGPR on systemic resistance of amaranth against the pigweed beetle.

Speakers

Zachary Williams

University of Maryland Eastern Shore

Co-authors

Corrie Cotton

University of Maryland Eastern Shore

Simon Zebelo

University of Maryland Eastern Shore

Thursday September 26, 2024 10:45am - 11:00am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

11:00am HST

CE 5 - Shade-Avoidance Responses of Kale and Lettuce Elicited by Far-Red Light Can Persist Under High-Light Intensity

Thursday September 26, 2024 11:00am - 11:15am HST

South Pacific 3

Far-red (FR; 700–750 nm) light induces shade-avoidance responses such as stem and leaf elongation and an increase in specific leaf area (SLA). Previous studies have reported that a high photon flux density (PFD) can mitigate the effects of FR light. However, limited research has explored the impacts of individual waveband PFDs on the effects of high total PFD (TPFD) in regulating FR-light responses. To address this gap, we conducted an experiment hypothesizing that the effects of a high FR fraction [FR-PFD divided by the sum of red (R; 600–699 nm) and FR PFD] on shade-avoidance responses would persist when the TPFD increases were solely from increases in R and FR PFDs. We grew kale (Brassica oleracea var. sabellica) ‘Red Russian’ and lettuce (Lactuca sativa) ‘Rex’ and ‘Rouxai’ under 12 lighting treatments with a 24 h∙d−1 photoperiod, TPFDs of 85, 170, 255, or 340 µmol∙m−2∙s−1, and FR fractions of 0.00, 0.17, or 0.33. The blue (400-499 nm) PFD was constant in all treatments and the alterations in the TPFDs were solely due to R and FR PFDs. Based on preliminary results, high FR fractions increased the leaf length of kale to a similar degree at all TPFDs except for no increase at the TPFD of 85 µmol∙m−2∙s−1. High FR fractions increased the leaf length of lettuce ‘Rex’ and ‘Rouxai’ to a similar degree at all TPFDs. In contrast, the SLA of kale did not respond to the FR fraction at any of the TPFDs. The SLA of lettuce ‘Rex’ and ‘Rouxai’ was increased by high FR fractions to a similar degree at all TPFDs except for no increase at the TPFD of 85 µmol∙m−2∙s−1. Contrary to the paradigm, our results suggest that FR-fraction effects can persist under a high TPFD when R and FR PFDs are elevated. Moreover, the lack of response of kale leaf length and lettuce SLA to the FR fraction at the lowest TPFD implies that a low R and FR PFD attenuates the effect of the FR fraction in eliciting shade-avoidance responses.

Speakers

Jiyong Shin

Michigan State University

Co-authors

Erik Runkle

Michigan State University

Thursday September 26, 2024 11:00am - 11:15am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

11:15am HST

CE 5 - Does Intermittent and Continuous Nutrient Flow Affect the Growth and Phytochemicals of Culinary Herbs in NFT Hydroponics

Thursday September 26, 2024 11:15am - 11:30am HST

South Pacific 3

Hydroponic cultivation has emerged as an innovative method for efficient and sustainable production of different crops because of year-round production and precise nutrient delivery. Light plays a major role when plants are grown in a controlled environment. Supplemental light is necessary for the physiological function of crops when grown in a hydroponics system. In nutrient film technique (NFT) hydroponic production, crops are usually produced with continuously flowing nutrient solutions. However, intermittent flow, where nutrient solutions are paused for periods of time instead of continuous cycling, has been proposed as a more efficient hydroponic system. Intermittent flow of nutrients increases the efficiency of hydroponic systems as it reduces the cost of running pumps continuously. Culinary herbs can be grown easily in NFT hydroponic systems. These herbs are a high-value crop and are a rich source of vitamins, nutrients, fibers, and phytochemicals that are known to fluctuate in concentration in different production systems. Yet it is not known if intermittent irrigation will impact phytochemicals in culinary herbs with or without supplemental lights in NFT production. This experiment investigated the effect of intermittent and continuous flow of nutrients in two culinary herbs, cilantro (Coriandrum sativum) and parsley (Petroselinum crispum) with or without supplemental lights. To regulate nutrient solution flow, the pump was turned on continuously in the continuous flow treatment, whereas it was turned on and off periodically for 30-minute intervals in the intermittent flow system. The herbs were grown for a month and different plant growth parameters like plant height, plant fresh weight, dry weight, root length (RL), total phenolic content (TPC), total flavonoid content (TFC) and proline were measured. Interestingly, nutrient delivery only affected plant height and plant fresh weight in cilantro. Plant height was greater in intermittent flow whereas plant fresh weight was greater in continuous flow. However, nutrient flow did not show any differences in other studied growth parameters in both herbs. Supplemental light significantly increased the root length, plant fresh weight, and dry weight of both herbs. TFC of cilantro was affected by the interaction of supplemental light and nutrient flow system with greater flavonoids in a continuous flow without supplemental light. In parsley, supplemental light increased the proline content. These findings suggest that cilantro and parsley can be grown easily in intermittent flow by reducing the associated cost of production. However, supplemental lighting is necessary to increase the yield of herbs.

Speakers

Abishkar Regmi

Texas Tech University

Co-authors

Catherine Simpson

Texas Tech University

Haydee Laza

Texas Tech University

Lindsey Slaughter

Texas Tech University

Naima Moustaid Moussa

Texas Tech University

Thursday September 26, 2024 11:15am - 11:30am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

11:30am HST

CE 5 - Adjusting Supplemental LED Light Intensities Based on Real-time Chlorophyll Fluorescence Measurements in a Greenhouse

Thursday September 26, 2024 11:30am - 11:45am HST

South Pacific 3

Precise and efficient control of supplemental lighting is vital to minimize electrical energy costs in controlled environment agriculture. Even though various environmental factors such as temperature, vapor pressure deficit, CO2 concentrations, and water status influence photosynthetic capacity, current supplemental light control strategies are controlled only based on ambient sunlight conditions. Meanwhile, chlorophyll fluorescence is widely used as an indicator of environmental stress and photosynthetic capacity on account of its easy and non-invasive measurement. A chlorophyll fluorescence-based biofeedback system has been proposed as an innovative approach for precise control of supplemental LED light intensities. The biofeedback system can dynamically optimize LED light intensities based on real-time measurements of chlorophyll fluorescence while allowing plants to decide the amount of supplemental light they need. The biofeedback system has been previously validated in a growth chamber, but its application in an actual greenhouse condition remains unexplored. The objective of this research was to implement the biofeedback system in a greenhouse environment for real-time control of supplemental light intensities based on photosynthetic activity. Additionally, the productivity and energy efficiency of the biofeedback strategy were evaluated and compared to conventional light control strategies. Two fluorometers (MINI-PAM; Heinz Walz, Effeltrich, Germany) were used to monitor the electron transport rate (ETR) and quantum yield of photosystem II (ΦPSII) every 10 minutes, and the Biofeedback system adjusted supplemental LED light intensities until the predefined target ETR and ΦPSII were achieved. Three popular greenhouse crops [lettuce (Lactuca sativa), sweet basil (Ocimum basilicum), and spinach (Spinacia oleracea L.)] were grown under five supplemental light conditions. Specific targets of 1) electron transport rate (ETR), 2) quantum yield of photosystem II (ΦPSII), 3) photosynthetic photon flux density (PPFD), 4) daily light integral (DLI), and 5) no control (ambient sunlight) were used to control supplemental light intensities. In contrast to conventional lighting control methods, the biofeedback system tailored supplemental light intensities according to not only sunlight levels but also temperature and humidity. The result underlines the effectiveness and energy efficiency of the biofeedback system that could integrate variable environmental factors in the greenhouse and apply them to adjust supplemental light intensities precisely.

Speakers

Suyun Nam

University of Georgia

Co-authors

Leonardo Bastos

University of Georgia

Mark Haidekker

University of Georgia

Melanie Yelton

Grow Big CEA Consultants

Rhuanito Ferrarezi

University of Georgia

Savithri Nambeesan

University of Georgia

Thursday September 26, 2024 11:30am - 11:45am HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

11:45am HST

CE 5 - Interactions of Far-Red Photons with Orange Photons or Red Photons: Photosynthetic Response, Morphology and Fruit Yield

Thursday September 26, 2024 11:45am - 12:00pm HST

South Pacific 3

Plant response from the interaction between far-red and orange photons were rarely known, compared to that of far-red and red photons. Recent previous studies have found application of supplemental orange photons increases the openness of tomato plant architecture, resulting in improved dry weight than supplemental blue, green and red photons. However, limited information is available on the effects of orange photons on plant growth, morphology, and photosynthetic efficiency. Thus, our objective was to quantify the effects of orange photons on growth and photosynthetic responses during long term crop cultivation, compared to red photons. Dwarf tomatoes ‘Red Robin’ were grown in a walk-in chamber with controlled environmental conditions for 96 days after sowing (day temp. 24.3 ± 0.4℃ / night temp. 19.8 ± 0.5℃ and RH 60.5 ± 3.5%). Four light spectral treatments were applied as follows: 1) B25G25O200 (orange), 2) B25G25R200 (red), 3) B25G25O165FR35 (O FR), and 4) B25G25R165FR35 (R FR) (subscripts denote photon flux densities in µmol m² s-1). All spectral treatments had the same total light intensity of 250 µmol m² s-1 with a 18-h photoperiod. Leaf photosynthetic rate was measured before the fruit stage under sole-source orange or red light, as well as under combination lights (RGB or OGB), in a random order. Plant height and main stem length significantly increased under the two spectral treatments with far-red photons (i.e., O FR or R FR), compared to treatments without far-red photons (i.e., orange and red treatments). In comparison between orange and red treatments (without far-red), total dry weight of orange treatment was significantly higher than in red. However, the trend was opposite in the treatments with far-red photons (O FR treatment was lower than R FR treatment). In comparison between with and without far-red photons, total leaf area and fruit dry weight under far-red photons were significantly higher than those in the treatments without far-red photons, whereas stem weight was lower. Brix° under with far-red photons was higher than the treatment without far-red, and that of orange treatment was higher than in the red. Photosynthesis rate under sole-source orange photons was higher than under red photons, but no significant difference was observed among under combination lights. Overall, our results indicated that application of orange photons instead of red photons led to improved biomass and fruit yields in dwarf tomato, resulting in enhanced openness in the canopy structure; however, the trends were reversed with the application of far-red photons.

Speakers

Seonghwan Kang

Texas A

Co-authors

Shuyang Zhen

Texas A

Thursday September 26, 2024 11:45am - 12:00pm HST
South Pacific 3

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 5

SUBJECT Growth Chambers and CE

12:00pm HST

Technology in Horticulture Collaboration Session

Thursday September 26, 2024 12:00pm - 1:00pm HST

Coral 4

A forum for discussion of potential collaborations with regards to technology in horticulture – i.e. biotechnology, UAVs, cameras, sensors, artificial intelligence, etc.

Thursday September 26, 2024 12:00pm - 1:00pm HST
Coral 4

Hort Theater & Collaboration Center

SUBJECT Technology, Professional Development/Career, Plant Biotechnology, Growth Chambers and CE

1:44pm HST

Growth Chambers and Controlled Environments 6 (CE 6)

Thursday September 26, 2024 1:44pm - 3:45pm HST

Coral 1

Timing Kale Growth for Peak Nutrition and Energy Efficiency in a Vertical, Hydroponic Indoor Container Farm - Skyler Brazel
Effects of Beneficial Bacterial Endophytes on Growth of Lettuce Plants, Transcriptome, and Root Microbiome in Hydroponic Systems - Chuansheng Mei
Soybean Speed Breeding: Optimizing Photoperiod for Maximizing Yield and Minimizing Time - Cristiane da Silva
Energy Modeling and Management to Improve the Sustainability of Indoor Farming - Ying Zhang
Increasing Circularity in Controlled Environment Agriculture using Anaerobic Digester Effluent as an Organic Fertilizer - Ana Martin Ryals
Utilizing Deep Learning for Hydroponic NFT Channel Spacing Optimization - Azlan Zahid
Modeling Evapotranspiration in Greenhouse and Indoor Cutting Propagation - Daniel Crawford
Effect of Nutrient Correction Intervals on Nutrient Imbalance, Plant Growth, Yield, and Fruit Quality of Melon (Cucumis melo L.) in a Closed Hydroponic System - Minju Shin

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Thursday September 26, 2024 1:44pm - 3:45pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

1:45pm HST

CE 6 - Timing Kale Growth for Peak Nutrition and Energy Efficiency in a Vertical, Hydroponic Indoor Container Farm

Thursday September 26, 2024 1:45pm - 2:00pm HST

Coral 1

As entrepreneurs look to find new ways to shorten the gap between farm and table in urban communities, many are considering vertical farming as an answer to the problem of limited growing space. The aim of this experiment is to determine the optimal harvest time in weeks for vertically grown, hydroponic kale (Brassica oleracea var. acephala cv. ‘Toscano’) based on morphological data, phytonutrient concentrations, energy, and yield. After a four-week germination period, kale was grown for up to eight weeks and harvested at eight different stages of growth, based on the number of weeks spent in the vertical system. When harvested, morphological parameters were measured, and samples were collected to analyze mineral nutrient content. Electrical Energy usage data was collected and presented as: Lighting, HVAC, and Other. Data was analyzed as a Randomized Complete Block Design with three blocks. Mean plant height, fresh leaf mass, and leaf dry mass all increased with growth stage, with the largest plants being observed at stage eight. Additionally, the greatest mean quantity of dead, diseased, or unconsumable leaves of 3.27 leaves per plant was observed at stage eight. Mineral nutrient concentrations of calcium, sulfur, and manganese increased through seven weeks (stage seven), after which a decrease was observed in stage eight. Decreases in concentration during stage eight was also observed for phosphorus, potassium, and magnesium, with negligible differences in the younger stages. No differences in energy data existed for the daily mean lighting, HVAC, and Other electrical consumption across all eight stages. Harvest data collected indicates that plants should be harvested prior to stage eight to maintain mineral nutrient content and minimize dead leaves and should be considered with total energy consumption to optimize farm productivity, energy efficiency, and nutritional content of plants. Further analysis of other primary and secondary metabolites alongside total energy consumption cost is necessary to identify the best stage of harvest maturity and nutritional quality for consumers relative to energy usage and production cost.

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Carl Sams

University of Tennessee

Devin Vitello

University of Tennessee - Knoxville

Katelynn Rector

University of Tennessee - Knoxville

Thursday September 26, 2024 1:45pm - 2:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:00pm HST

CE 6 - Effects of Beneficial Bacterial Endophytes on Growth of Lettuce Plants, Transcriptome, and Root Microbiome in Hydroponic Systems

Thursday September 26, 2024 2:00pm - 2:15pm HST

Coral 1

Controlled environment agriculture will play an important role in feeding the increasing world population as urbanization is expanding, and arable land is decreasing. Higher yields will help offset the initial high cost for building hydroponic production facilities. Beneficial bacterial endophytes have been receiving more attention in sustainable agriculture practices because they can promote plant growth, enhance nutrient uptake, and inhibit pathogen growth. The Institute for Advanced Learning and Research has established a bacterial endophyte library of more than 2000 strains and found that some bacterial endophytes significantly increased the growth of tall fescue KY31 in vitro, up to 8-fold compared with untreated control plants. In previous paper, we reported that Pseudomonas psychrotolerans IALR632 significantly promote lettuce growth in hydroponic systems. In this study, we investigated the molecular and microbiological mechanisms these bacteria exhibit for plant growth promotion in hydroponic systems through plant gene expression with RNAseq and root bacterial community changes through microbiome analysis after bacterial inoculation. Lettuce (Lactuca sativa) cultivar ‘Green Oakleaf’ was inoculated with Pseudomonas psychrotolerans IALR632 one week after seeds were sown and transplanted to nutrient film technique (NFT) hydroponic units one week after bacterial inoculation. Samples were taken at 4, 10, and 15 days after lettuce seedlings were transplanted for gene expression analysis. Root samples were taken 15 days after transplantation for microbiome analysis. Anosim, NMDS, and PCoA analyses indicated bacterial community changes in inoculated plants. The top genus relative abundance was unclassified bacteria with 87% in IALR632 treatment and 85% in control (p=0.0136). In the next top 24 genus’s relative abundance, IALR632 inoculation dramatically increased Sediminibacterium, Hyphomicrobium, Sphingobium, Devosia, Mycobacterium, Rhodoplanes, and Runella by 68%, 114%, 72%, 158%, 513%, 103% and 1920%, respectively, and reduced Methylotenera, Rhizobium, and Sphingomonas by 68%, 62% and 45%, respectively. RNAseq data showed that there were 135, 2059, and 9319 DEG between the control and bacterial treatment at 4, 10, and 15 days, respectively. These DEG are being analyzed for pathways involved in plant growth promotion.

Speakers

Chuansheng Mei

Institute for Advanced Learning and Research

Co-authors

Robert Chretien

Institute for Advanced Learning and Research

Sajeewa Amaradasa

Institute for Advanced Learning and Research

Scott Lowman

Institute for Advanced Learning and Research

Thursday September 26, 2024 2:00pm - 2:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:15pm HST

CE 6 - Soybean Speed Breeding: Optimizing Photoperiod for Maximizing Yield and Minimizing Time

Thursday September 26, 2024 2:15pm - 2:30pm HST

Coral 1

Speed breeding is a cutting-edge technology, that utilizes controlled environments to significantly reduce plant generation time, thereby accelerating breeding and research programs. The manipulation of temperature, irrigation, phytohormones, and light are the main ways to reduce plant cycles in speed breeding programs. However, changing these factors can result in decreased yield efficiency, which can also affect the quality of a speed-breeding program. This study aimed to increase seed production without increasing harvest time in soybean plants, a short-day plant, by using different photoperiod regimes. Two soybean (Glycine max) varieties, S16-14801C and CZ7570LL, were grown from seeds in 11-L pots containing peat moss-based substrate in growth chambers with controlled temperature (27 ± 0.5 ˚C), CO2 (475 ± 15 µmol mol-1), humidity (70 ± 5.0%), and light (300 ± 5 µmol m-2 s-1 at table; 20% blue, 10% green, 70% red). One week after germination, seedlings were exposed to four different photoperiod regimes: i) 10 h (0 w at 18 h); ii) two weeks at 18 h and then 10 h (2 w at 18 h); iii) four weeks at 18 h and then 10 h (4 w at 18 h) and iv) six weeks at 18 h and then 10 h (6 w at 18 h). The light fixtures were not adjusted over plant height following industry practices. The plants were harvested ten days after 95% of the pods had attained maturity (R8 stage). For both varieties, the number of pods and seeds and seed weight per plant increased linearly, with the increase in the number of weeks at 18 h. Thus, the number of pods, seeds, and seed weight of plants at 6 w at 18 h were at least 5-fold higher than in plants at 0 w at 18 h. Similarly, plants grown at 6 w at 18 h presented 4-fold higher biomass than plants grown at 0 w at 18 h. However, the increased seed yield and biomass accumulation did not result in a longer plant cycle; plants of both varieties at 6 w at 18 h were harvested 32 days before plants at 0 w at 18 h. Here, we demonstrated that seed yield can be increased and harvest time decreased by manipulating the photoperiod. These findings can help plant breeders in identifying the most suitable method for growing soybean plants in a shorter period, while also ensuring high seed production.

Speakers

Cristiane da Silva

Postdoctoral Research Scholar, North Carolina State University

Co-authors

Cristian Collado

North Carolina State University

Jan Van Butsele

BASF

Ricardo Hernandez

North Carolina State University

Richard Jack

BASF

Will Bednarz

BASF

Thursday September 26, 2024 2:15pm - 2:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:30pm HST

CE 6 - Energy Modeling and Management to Improve the Sustainability of Indoor Farming

Thursday September 26, 2024 2:30pm - 2:45pm HST

Coral 1

Controlled environment agriculture (CEA) is considered one of the most efficient ways of crop production. CEAs have the ability to control environmental conditions to maximize crop production. Indoor farms are considered one of the CEA systems that precisely control the environment, leading to high energy consumption in lighting, heating, cooling, and humidity control requirements. Enhancing the energy use efficiency (EUE) of indoor farms requires a better understanding of the energy characteristics of the system and crop production is needed. In this study, a steady state energy model and a machine learning based crop growth model were developed to evaluate energy-saving strategies for indoor lettuce production. The strategies included shifting photoperiod, utilizing heat tolerant crops, and adjusting air temperature settings at four different locations (Phoenix, AZ, Los Angeles, CA, Jacksonville, FL, and Boston, MA). The results showed that cultivar selection plays an important role in EUE improvement. Using high temperature settings with heat tolerant cultivars can increase the EUE of the system. However, increasing temperature setting alone does not significantly reduce energy consumption because of the increasing amount of energy needed for dehumidification. The geographical location of the indoor farm also affects energy consumption because of the different outdoor climate conditions. Boston, MA, which has the coldest outdoor air temperature, had the lowest energy consumption overall compared to the other three locations. Lastly, changing the photoperiod schedule from daytime to nighttime can reduce the electricity costs dramatically by avoiding the peak rate of electricity despite not having a significant reduction in energy consumption.

Speakers

Ying Zhang

University of Florida

Co-authors

German Sandoya

University of Florida

Kale Harbick

USDA-ARS

Nikolay Bliznyuk

University of Florida

Tanapol Leelertkij

University of Florida

Thursday September 26, 2024 2:30pm - 2:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:45pm HST

CE 6 - Increasing Circularity in Controlled Environment Agriculture using Anaerobic Digester Effluent as an Organic Fertilizer

Thursday September 26, 2024 2:45pm - 3:00pm HST

Coral 1

As global population and stress on our natural resources increases, we need to rethink how/where we produce food with emphasis on recycling resources such as carbon, water, and nutrients. Controlled environment agriculture (CEA) is gaining increasing attention due to its potential for improving resource use efficiency compared to traditional field-based agriculture. This project investigated a novel approach for treating hydroponics irrigation water and recovering nutrients from vegetable waste for reuse in CEA systems. An integrated anaerobic/aerobic biological treatment process was investigated. Anaerobic digester effluent was nitrified via an aerobic membrane bioreactor process to produce a liquid organic fertilizer supplement (nADE). The nADE was evaluated as a nutrient source for indoor hydroponic and greenhouse soilless drip-irrigation lettuce cultivation. Lettuce yield, tissue nutrient content, water quality, and nutrient uptake efficiency were compared between the nADE treatment and a commercial fertilizer control for each CEA system. The lettuce grown on nADE demonstrated similar or higher yields, more leaves, and elevated tissue nutrient content than the control. The nADE media improved N and P uptake efficiency in the drip-irrigation system but decreased K, Ca, and Mg uptake efficiency, possibly from the over-application of these nutrients. Further research is needed to optimize the integrated treatment system as well as nADE dosing. The study demonstrates a circular bioeconomy approach to decrease dependency on inorganic fertilizers while benefiting crop yield and quality.

Speakers

Ana Martin Ryals

University of Florida

Co-authors

Haimanote Bayabil

University of Florida

Kelsey Vought

University of Florida

Thursday September 26, 2024 2:45pm - 3:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:00pm HST

CE 6 - Utilizing Deep Learning for Hydroponic NFT Channel Spacing Optimization

Thursday September 26, 2024 3:00pm - 3:15pm HST

Coral 1

In controlled environment agriculture (CEA), maintaining effective plant spacing throughout the crop growth cycle is crucial for efficient resource (light, water, space, and nutrients) utilization to achieve optimal crop yield and quality. Overcrowded or overlapping plant leaves could cause inefficient light exposure to plants/parts of plants, negatively affecting their growth. Additionally, reduced airflow makes overcrowded plants prone to diseases and foliage damage. Meanwhile, sparse plant spacing could result in inefficient space and light utilization. Traditional plant spacing adjustment relies on expert knowledge and manual labor, which is time-consuming, labor-intensive, and costly. Computer vision-based automatic plant space adjustment could help with data-driven decision-making and reduce labor dependency. This study aims to develop a deep learning-based computer vision approach to estimate the effective plant spacing by extracting the morphological characteristics of plants and NFT (nutrient film technique) channels during different plant growth stages. A total of 576 lettuce plants were grown in an NFT channel-based hydroponics system in a controlled environment. Then, RGB-D information of these plants and NFT channels was collected each day for three weeks from planting to harvesting. Then, CNN (convolutional neural network) was employed to extract the plant and NFT channel feature information. Then, the spatial pyramid pooling approach was used to encode and decode the contextual information and segment the plants and NFT channels. This approach helped to achieve an F1-score of 0.90 on the test dataset to estimate space between plants and NFT channels. These results show the potential of the proposed approach for automated plant space adjustment for efficient resource utilization.

Speakers

Azlan Zahid

Texas A

Thursday September 26, 2024 3:00pm - 3:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:15pm HST

CE 6 - Modeling Evapotranspiration in Greenhouse and Indoor Cutting Propagation

Thursday September 26, 2024 3:15pm - 3:30pm HST

Coral 1

Current mist irrigation practices in plant propagation do not represent the variable rate of water loss experienced in a greenhouse environment and often rely on grower experience for adjusting irrigation settings. Automated control logic for these systems can be improved by considering climate data to predict the real-time water loss in the propagation environment. The objectives of this study were to 1) identify the impacts of environmental parameters on the water loss of young plants in greenhouses and indoor environments and 2) develop an evapotranspiration model based on the key parameters identified to achieve weather-based mist irrigation control for resource-efficient plant propagation in controlled environment agriculture. Data sets that include climate data, water applied, and water loss were collected in greenhouse sunlight and indoor sole-source LED environments with unrooted chrysanthemum cuttings. Trials were completed in June and September in 2023 and February in 2024 to collect diverse minute-by-minute data in each environment. Measurements using load cells indicated highly variable water loss in the greenhouse environment. Conversely, in the indoor environment with lower and constant photosynthetic photon flux density (PPFD) and reduced vapor pressure deficit via a fog system, rate of water loss was lower and consistent over time. The key parameters for modeling water loss, found using stepwise regression, were PPFD, leaf temperature, and air vapor pressure (temperature and relative humidity). These climate parameters were correlated with water loss data over time to yield a simple evapotranspiration equation that could be programmed into commercial environmental control systems to improve current irrigation scheduling programs. By improving the control of mist irrigation to take climate data into account, growers have the potential to reduce crop losses (“shrinkage”), reduce rooting time, and improve water use efficiency.

Speakers

Daniel Crawford

University of Florida

Thursday September 26, 2024 3:15pm - 3:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:30pm HST

CE 6 - Effect of Nutrient Correction Intervals on Nutrient Imbalance, Plant Growth, Yield, and Fruit Quality of Melon (Cucumis melo L.) in a Closed Hydroponic System

Thursday September 26, 2024 3:30pm - 3:45pm HST

Coral 1

In South Korea, where many fruit vegetable crops are grown in greenhouses, the practice of continuous cropping in the same soil environments often leads to significant issues To mitigate these problems, there has been a shift from soil-based to hydroponic cultivation. While hydroponics is recommended as a sustainable agricultural practice, non-recirculating systems can lead to environmental contamination as the nutrient-rich drainage is discharged outside, affecting soil and water quality. However, recirculating hydroponics, which reuses the drained nutrient solution, conserves water and fertilizer, thereby promoting sustainable and eco-friendly agriculture. As plants grow, their nutrient requirements change with each growth stage. Reusing the drainage without adjusting its nutrient content can lead to imbalances. Periodic nutrient correction is crucial in recirculating hydroponic systems. This study was conducted to find the optimal nutrient correction intervals for growing melons hydroponically in a recirculating system, analyzing the effects of different correction intervals (every 2 weeks, every 4 weeks, and no correction) on nutrient imbalances and their impact on melon growth and fruit development. In the case of melons, post-fruit set, as plants shift from vegetative to reproductive growth, changes in nutrient uptake lead to imbalances. In this experiment, the nutrient composition between treatments corrected periodically did not differ significantly, but was markedly different from the uncorrected treatments. In uncorrected systems, the continual reuse of the drainage altered the balance of anions and cations, with anions increasing by approximately 4% and cations decreasing by the same margin, disrupting the nutrient balance and causing pH fluctuations. Specifically, there was a 10-12% difference in the ratios of cations such as K+ and Ca2+, and a 7% difference in anions like NO3-. Despite these nutritional variances, statistical analysis revealed no significant differences in the growth and fruit characteristics among the treatments.

Speakers

Minju Shin

Rural Development Administration

Co-authors

Ho Jeong Jeong

Rural Development Administration

Jin Hyun Kim

Rural Development Administration

Seungri Yoon

Seoul National University

Thursday September 26, 2024 3:30pm - 3:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

4:00pm HST

Interest Group Session: Sensing the Plant, for the Farmer's Benefit! A Historical Perspective Reflecting on the Work of Marc van Iersel

Thursday September 26, 2024 4:00pm - 6:00pm HST

Nautilus 1

The recent loss of our colleague Marc van Iersel reminds us of the reasons our work in horticulture is so important. Marc's career was devoted to developing processes that judiciously utilized sensors to create efficient strategies to optimize crop quality and production for the grower. By examining the path of van Iersel’s work, we can understand how directed, mindful research can move quickly from the hands of the researcher to the farmer. Marc’s early work centered around developing smart irrigation systems utilizing biofeedback to measure soil moisture, with the goal of reducing water usage. More recently, Marc’s work integrated LED lighting with sensors including light sensors, moisture sensors, and low cost canopy and fluorescence detection to generate strategies for precise, energy efficient control of lighting in greenhouse and vertical growing platforms. Marc frequently consulted with growers to understand their needs and challenges, allowing the grower’s needs to frame his research. Marc also mentored the development of students, fellows, and colleagues in their own research, helping them discover how their programs could unfold in directions which would be most valuable. In this session we will examine the history of Marc’s research and continued work by colleagues, to ensure his lessons in how to provide practical answers for commercial horticulture are not lost. This two-hour session will include presentations from Marc's students and colleagues, and conclude with a 30-minute moderated Q&A/discussion.

Coordinator(s)

Jennifer Boldt, United States Department of Agriculture, Agricultural Research Service, Toledo, OH, United States
Neil Mattson, Cornell University, Ithaca, New York, United States
Melanie Yelton, Grow Big, United States

Bruce Bugbee, Utah State University, Plants, Soils, and Climate, Logan, Utah, United States
A Life Filled with People, Plants, Photons, and Perseverance (15 mins)
Stephanie Burnett, University of Maine, School of Food and Agriculture, Orono, Maine, United States
Impact on Sensor Automated Irrigation and Student Mentoring (15 mins)
Rhuanito Ferrarezi, University of Georgia, Horticulture, Athens, Georgia, United States
The Man Behind the Legend (15 mins)
Andrew Ogden, University of Georgia, Griffin, Georgia, United States
Shuyang Zhen, Texas A&M University, United States
The Light He Shined: Translating Plant Physiology into Smart Lighting Control Strategies (15 mins)
Leonardo Lombardini, University of Georgia, Horticulture, Athens, Georgia, United States
Honoring Marc's Legacy (15 mins)

Moderator

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Neil Mattson

Cornell University

Melanie Yelton

GrowBig Consulting

Melanie Yelton, Dr. Yelton leverages over 25 years of plant science leadership to guide controlled agriculture entities towards climatically resilient food systems. Via her consultancy company, GrowBig, she advises controlled environment agriculture farms, lighting partners and R... Read More →

Speakers

Stephanie E. Burnett

University of Maine

Bruce Bugbee

Rhuanito Ferrarezi

Andrew Ogden

Shuyang Zhen

Leonardo Lombardini

ASHS International Division VP

Thursday September 26, 2024 4:00pm - 6:00pm HST
Nautilus 1

Interest Group Session

SUBJECT Growth Chambers and CE

9:00am HST

Keynote Speaker: Kerry Kakazu

Friday September 27, 2024 9:00am - 9:45am HST

Coral 3

"Vertical Farming in Hawaiʻi: Design Considerations for our Unique Environment"

Kerry Kakazu, PhD is the President of MetroGrow Hawaii, the first vertical farm in the state. He has a masters and PhD in Plant Physiology from the University of California at Davis. After a career in academia doing research, teaching and administration he combined his interests in plant science, technology and the local food scene to create MetroGrow Hawaii in 2014. The farm has been providing premium leafy greens to local restaurants and gourmet markets since its founding and is now exploring ways to expand vertical farming to significantly increase food self-sufficiency and security in Hawaiʻi.

Speakers

Kerry Kakazu

Friday September 27, 2024 9:00am - 9:45am HST
Coral 3

Keynotes and Featured Sessions

SUBJECT Consumer Hort and Master Gardeners, Growth Chambers and CE, Vegetable Crops

9:59am HST

Growth Chambers and Controlled Environments 7 (CE 7)

Friday September 27, 2024 9:59am - 11:45am HST

Nautilus 1

Foliar Nutrient Concentrations of Strawberry Mother and Daughter Plants Grown in Controlled Environments - Jennifer Boldt
Increasing Nutrient Solution Electrical Conductivity Increases Vegetative Growth of Strawberry - Erin Yafuso
Impact of Artificial Chilling on Yields of Indoor-Propagated Strawberry Plants in California, Florida, and North Carolina - Ibraheem Olamide Olasupo
The Nitrate to Ammonium Ratio Impacts Strawberry Runnering and Daughter Plant Number - Erin Yafuso
Effect of Monosilicic Acid on Growth and Physiology of Lettuce - Seunghyun Choi
Light Intensity and Zinc Biofortification Effect on Yield and Nutritional Quality of Pea and Radish Microgreens - Pradip Poudel
Evaluation of Liquid Organic Fertilizers for Containerized Production of Leafy Greens in a Controlled Environment - Uttara Samarakoon

Moderator

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Friday September 27, 2024 9:59am - 11:45am HST
Nautilus 1

Oral Sessions, Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:00am HST

CE 7 - Foliar Nutrient Concentrations of Strawberry Mother and Daughter Plants Grown in Controlled Environments

Friday September 27, 2024 10:00am - 10:15am HST

Nautilus 1

Few published studies provide foliar tissue nutrient concentrations for strawberry (Fragaria × ananassa) mother and daughter plants. Recommendations primarily focus on tissue concentrations for field-grown plants during fruit production. As controlled environment production of strawberry increases, a need exists to define tissue nutrient concentration ranges for healthy foliar tissue, for both vegetative and fruit production. Defining deficient, sufficient, and toxicity ranges will assist growers in selecting nutrient solution recipes and correcting nutritional issues that arise. The objective of this study was to identify nutrient concentration ranges for healthy strawberry mother and daughter plants grown in controlled environments. Foliar tissue samples were collected from two separate experiments: 1) ‘Albion’, ‘Fronteras’, and ‘Monterey’ grown in a peat-based substrate, and 2) ‘Monterey’ grown indoors in deep water culture. Plants received a modified strawberry nutrient solution (Yamazaki) that provided 100 mg·L-1 nitrogen (N). The percent total N provided as ammonium (NH4 ) ranged from 0% to 40% in both experiments. Plants did not exhibit any visual symptoms of foliar nutrient deficiencies or toxicities. Foliar tissue from mother (n=72) and daughter plants (n=144) were collected and analyzed individually. Nutrient concentration ranges comprised the middle 75% of plant samples (12.5% – 87.5% quantiles). Mother plant macronutrient concentrations ranged from 2.12%–2.64% nitrogen (N), 0.53%–1.23% phosphorus (P), 2.05%–3.88% potassium (K), 2.01%–3.36% calcium (Ca), 0.33%–0.56% magnesium (Mg), and 0.14%–0.28% sulfur (S). Daughter plant foliar macronutrient concentrations ranged from 2.18%–3.38% N, 0.49%–0.92% P, 2.20%–4.19% K, 1.01%–3.03% Ca, 0.31%–0.53% Mg, and 0.15%–0.30% S. Mother plant foliar micronutrient concentrations ranged from 158–233 mg·kg-1 boron (B), 1.5–5.6 mg·kg-1 copper (Cu), 57–587 mg·kg-1 iron (Fe), 131–384 mg·kg-1 manganese (Mn), and 11–29 mg·kg-1 zinc (Zn). Daughter plant foliar micronutrient concentrations ranged from 69–212 mg·kg-1 B, 1.2–4.5 mg·kg-1 Cu, 56–347 mg·kg-1 Fe, 78–315 mg·kg-1 Mn, and 18–36 mg·kg-1 Zn. In general, these macro- and micronutrient ranges overlap between mother and daughter plants. These values represent a first step in developing and refining foliar nutrient ranges for strawberry mother and daughter plants in controlled environments.

Speakers

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Co-authors

Erin Yafuso

United States Department of Agriculture

Friday September 27, 2024 10:00am - 10:15am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:15am HST

CE 7 - Increasing Nutrient Solution Electrical Conductivity Increases Vegetative Growth of Strawberry

Friday September 27, 2024 10:15am - 10:30am HST

Nautilus 1

Established guidelines for electrical conductivity (EC) for strawberry (Fragaria ×ananassa) fruit production exist for plants grown in soilless substrates. However, EC recommendations for strawberry mother plants may differ when the goal is prolific runnering instead of flowering and fruiting. Our objective was to evaluate the impact of EC concentration strawberry runner and daughter number. Strawberry ‘Monterey’ were grown in a greenhouse in 19.1-cm diameter pots filled with a soilless substrate (50 perlite : 25 coco coir : 25 peat). To formulate the EC treatments, all components of a strawberry nutrient solution (Yamazaki) increased equally, which corresponded to nitrogen (N) concentrations of 50, 100, 150, 200, 300, and 400 mg·L-1 N. After adding 0.8 mM potassium bicarbonate as a buffer and adjusting pH to 5.7, the final nutrient solution EC values were 0.9, 1.6, 2.3, 2.8, 3.9, and 4.9 mS·cm-1. After 12 weeks of treatment, runner and daughter plant number, morphological assessments, and mother plant leaf burn index were evaluated. The qualitative assessment of leaf burn utilized a 1 to 5 scale (1 = no tip burn; 2 = mild, margins of ≥ 3 leaves; 3 = moderate, necrosis on at least half of ≥ 3 leaves; 4 = moderate to severe, complete necrosis on ≥ 3 leaves; and 5 = severe, complete necrosis on ≥ 4 leaves and necrosis of daughter plants). Leaf burn values ranged from 1.6 ± 0.2 (± SE) in the 50 mg·L-1 N treatment to 5.0 ± 0.0 in the 400 mg·L-1 N treatment. Runner number exhibited a quadratic response and ranged from 2 ± 0 at 50 mg·L-1 N to 7 ± 1 at 300 mg·L-1 N. Daughter plant number also exhibited a quadratic response. It increased from 14 ± 3 at 50 mg·L-1 N to 44 ± 4 at 200 mg·L-1 N, then declined to 30 ± 13 at 400 mg·L-1 N. Total plant biomass (mother plant, stolons, and daughter plants) exhibited a quadratic relationship. It increased from 23.5 ± 4.0 g at 50 mg·L-1 N to 65.9 ± 7.9 g at 200 mg·L-1 N, then declined to 40.0 ± 5.2 g at 400 mg·L-1 N. Overall, the optimal nutrient solution EC range for strawberry mother plants was 100 to 200 mg·L-1 N (or 1.6 to 2.8 mS·cm-1). In this range, mother plants produced a high number of runners and daughter plants, with minimal leaf burn due to high substrate EC values.

Speakers

Erin Yafuso

United States Department of Agriculture

Co-authors

Jennifer Boldt

United States Department of Agriculture

Friday September 27, 2024 10:15am - 10:30am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:30am HST

CE 7 - Impact of Artificial Chilling on Yields of Indoor-Propagated Strawberry Plants in California, Florida, and North Carolina

Friday September 27, 2024 10:30am - 10:45am HST

Nautilus 1

Unavailability of pathogen-free strawberry propagules in commercial quantities necessitates the development of a novel completely indoor precision propagation technology for the crop, which also seeks to reduce dependence on soil fumigants including methyl bromide. Artificial chilling of plug plants could also enhance transplant vigor, flowering, and yield of strawberry. Under this novel technology, strawberry tips which consisted of five short day (SD) cultivars (Fronteras, Camarosa, Chandler, Sensation and Brilliance) and one long day (LD) cultivar (Monterey) were collected from tissue cultured mother plants. Plants were propagated under completely controlled environment (CE) conditions in a plant factory. Strawberry daughter plants were rooted in 50 cc trays filled with a commercial substrate and were arranged in the controlled environment under 90 – 100 % humidity, 27 °C temperature, 80 – 100 µmol m-2 s-1 light (LED), 18 hours photoperiod, and fertigated using the ebb and flow technique for 28 days. Our hypothesis was that artificial chilling will improve plant vigor and yield of CE-propagated strawberry transplants. We therefore assessed the impact of 350 – 450 hours of artificial chilling on the plant performance and yield of the transplants in four different locations in the US. Monterey, Brilliance, and Sensation cultivars received 350 hours of chilling while Fronteras, Chandler, and Camarosa cultivars were chilled for 450 hours. Strawberry plug plants (chilled and no-chill) were planted in replicated field trials in California, Florida, and North Carolina. Camarosa and Chandler cultivars were transplanted in North Carolina, Fronteras in Southern California, Monterey in Central California, while Brilliance and Sensation were transplanted in Florida. Preliminary results show improved vigor and yield from chilled plants in Florida and North Carolina field trials, while no differences were observed in California. Final results of the study will be shared during the conference.

Speakers

Ibraheem Olamide Olasupo

Postdoctoral Research Scholar, North Carolina State University

Co-authors

Calyssa Stevenson

North Carolina State University

Gerald Holmes

Cal Poly San Luis Obispo

Gina Fernandez

North Carolina State University

Mark Hoffmann

North Carolina State University

Oleg Daugovish

University of California Cooperative Extension

Ricardo Hernandez

North Carolina State University

Samantha Simard

Cal Poly- San Luis Obispo

Shinsuke Agehara

University of Florida

Friday September 27, 2024 10:30am - 10:45am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:45am HST

CE 7 - The Nitrate to Ammonium Ratio Impacts Strawberry Runnering and Daughter Plant Number

Friday September 27, 2024 10:45am - 11:00am HST

Nautilus 1

The use of controlled environments to produce disease-free vegetative clones of strawberry (Fragaria ×ananassa) is increasing. However, protocols for mother plant management that optimize runner and daughter plant number need to be developed. Studies have shown that decreasing the fraction of nitrogen (N) supplied as nitrate (NO3-) can encourage vegetative growth in other crops. Our objective was to identify the %NO3--N that maximized runner and daughter plant number. Strawberry ‘Albion’, ‘Fronteras’, and ‘Monterey’ were grown in 19.1-cm pots filled with a peat-based substrate. Plants were irrigated with a modified strawberry nutrient solution (Yamazaki) that provided a total of 100 mg·L-1 N. The percent of total N supplied as NO3- ranged from 0% to 100%, with the remainder supplied as ammonium (NH4 ). Runners and daughter plants were harvested after eight and 16 weeks of treatment. The impact of %NO3- on cumulative runner number was cultivar specific. ‘Albion’ was not impacted, and the overall mean was 9 ± 1 (± SE).‘Fronteras’ exhibited a quadratic response. It increased from 10 ± 2 at 0% NO3- to 17 ± 2 at 60% NO3-; the calculated maximum runner number was with 64% NO3-. ‘Monterey’ exhibited a linear increase, from 14 ± 1 at 0% NO3- to 22 ± 1 at 100% NO3-. The impact of %NO3- on cumulative daughter plant number was also cultivar specific. ‘Abion’ exhibited a linear increase, from 28 ± 2 at 0% NO3- to 37 ± 10 at 100% NO3- . ‘Fronteras’ exhibited a quadratic response and increased from 19 ± 2 at 0% NO3- to 45 ± 7 at 60% NO3-. ‘Monterey’ also exhibited a quadratic response and increased from 49 ± 4 at 0% NO3- to 90 ± 7 at 80% NO3-. Calculated maximum daughter plant number occurred at 66% and 81% NO3- in ‘Fronteras’ and ‘Monterey’, respectively. Overall, at least 60% NO3- provided robust runner and daughter plant number, but the response depended on cultivar evaluated. ‘Monterey’ and ‘Albion’ appear to prefer a higher %NO3- than ‘Fronteras’ for maximum runner and daughter plant number.

Speakers

Erin Yafuso

United States Department of Agriculture

Co-authors

Jennifer Boldt

United States Department of Agriculture

Friday September 27, 2024 10:45am - 11:00am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:00am HST

CE 7 - Effect of Monosilicic Acid on Growth and Physiology of Lettuce

Friday September 27, 2024 11:00am - 11:15am HST

Nautilus 1

Due to the high operation costs of indoor crop production, improving resource use efficiency to reduce costs has gained importance for sustainability in recent years. Silicon (Si) is not an essential plant nutrient since it is not a component of any structural or metabolic molecule, and plants do not suffer from Si deficiency. However, Si applications have shown beneficial effects on various crops, including improved growth, quality, stress tolerance, and water use efficiency (WUE). This study evaluated the effects of Si on indoor lettuce production to enhance lettuce growth and WUE. Two-week-old lettuce seedlings (Lactuca sativa cv. ‘Green Forest’ and ‘Rouxai’) were transplanted into 5-L deep water culture systems and grown for four weeks in a custom growth chamber with an average temperature/relative humidity of 22.4°C/58.8% and light intensity of 230 µmol/m²/s PPFD. The nutrient solution was weighed and replenished weekly. Si (DUNE™ stabilized monosilicic acid) was applied weekly to plants following two application methods (RA=root application and FS=foliar spray) and three concentrations (Control=0 ppm, C1=264 ppm, and C2=528 ppm). RA C1 significantly improved the shoot fresh weights (FW) and dry weights (DW) of both lettuce cultivars, while FS C1 was less effective than RA. Root growth showed the opposite trend, with FS C1 having the highest root FW and DW of both cultivars. However, root morphology showed cultivar-specific responses, with RA C1 producing the highest root length and surface area in ‘Green Forest’ and FS C1 the highest root surface area and volume in ‘Rouxai.’ WUE was significantly improved by RA C1, RA C2, and FS C2 in ‘Green Forest’ and RA C1 in ‘Rouxai’ compared to the control. Taken together, root application of Si at C1-264 ppm concentration most effectively improved the indoor lettuce growth and WUE.

Speakers

Seunghyun Choi

Postdoctoral research associate, Texas A&M Agrilife Research

Co-authors

Daniel Leskovar

Texas A

Joshua Harvey

Texas A

Vijay Joshi

Texas A

Friday September 27, 2024 11:00am - 11:15am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:15am HST

CE 7 - Light Intensity and Zinc Biofortification Effect on Yield and Nutritional Quality of Pea and Radish Microgreens

Friday September 27, 2024 11:15am - 11:30am HST

Nautilus 1

Zinc (Zn) is a micronutrient crucial for human health, impacting gene expression, cell division, and immune system development. Zinc deficiency affects about 17% of the global population, particularly children, pregnant women, and elderly people, and can lead to disorders and even death. Agronomic biofortification implemented by applying Zn-enriched solutions via fertigation to increase crops Zn content may be a valuable strategy to combat Zn deficiencies. Microgreens, known for their nutrient density, rapid growth cycle, and low phytic acid content, are emerging as promising candidates for Zn agronomic biofortification. However, research is needed to evaluate the effect of factors like light intensity and genotype which can affect Zn accumulation in microgreens. To this purpose, a study was conducted to examine the effect of Zn application rate (0, 5, 10, and 15 mg/L) and light intensity (100, 200, 300, and 400 µmol/m2/s) on yield components, mineral content, and phytochemical profile of pea and radish microgreens. The study revealed that Zn concentration increased with increasing concentration of Zn applied in both species. In peas, a 4-fold increase was observed when applying 15 mg/L of Zn without affecting fresh and dry biomass, while an almost 13-fold increase of Zn content was observed in radish, associated with a 7.8% reduction of fresh biomass and no effects on radish microgreens dry biomass. However, with the increase of Zn content, there was a reduction in Fe concentration in both peas and radish microgreens. The light intensity did not affect Zn content in both species; however, it affected the concentration of macro and other microelements and influenced yield, but the result varied by species. In pea microgreens, low light intensity determined higher fresh biomass but did not affect dry biomass. Instead, the opposite result was observed in radish microgreens; light intensity did not affect fresh yield but increased dry biomass with increasing the level of light intensity applied. Regarding the nutritional profile, total phenols, total antioxidants, and flavonoids increased with increasing Zn concentration and light intensity in both pea and radish microgreens. In conclusion, Zn fertigation effectively enhanced Zn in pea and radish microgreens, and although light intensity had no effect on Zn content, contributed to improve their nutritional profile. These findings provide valuable insights into the production technique of Zn biofortified microgreens and the potential enhancement of their overall nutritional profile using agronomic biofortification techniques.

Speakers

Pradip Poudel

The Penn State University

Pradip

Co-authors

Francesco Di Gioia

The Penn State University

Friday September 27, 2024 11:15am - 11:30am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:30am HST

CE 7 - Evaluation of Liquid Organic Fertilizers for Containerized Production of Leafy Greens in a Controlled Environment

Friday September 27, 2024 11:30am - 11:45am HST

Nautilus 1

Organic farming practices, such as the use of organic substrates, fertilizers, pesticides, and biological control, are gaining popularity in controlled environment agriculture (CEA) since soilless production was approved for organic certification in the US. Our past study showed that liquid organic fertilizers are more effective than substrate-incorporated compost fertilizers. Although many liquid organic fertilizers are commercially available, they vary widely in their nutritional composition. Therefore, selection of a suitable fertilizer can be complicated and confusing for CEA growers. The current study aimed to evaluate the effectiveness of different liquid organic fertilizers and compare their performance with that of a synthetic fertilizer for growing lettuce in two different containerized hydroponic systems. Two greenhouse experiments were conducted in a randomized block design with five replicates. In Experiment 1, two types of container (regular container and Dutch bucket) and three fertilizers (earthworm castings and kelp (ECK), molasses with other natural plant extracts (MPE), and hydrolyzed fish protein (HFP)) were considered. The fertilizers were selected from the Organic Materials Review Institute (OMRI) list based on their nutrient profile and reports from other studies. In Experiment 2, selected liquid organic fertilizers (ECK, MPE) were compared with a commercial synthetic fertilizer (CSF). In Experiment 1, ECK performed better, resulting in 28% greater fresh weight, 20% greater dry weight, 48% greater leaf area, 26% greater shoot width, 126% greater average root fresh weight, and 47% greater root length in containerized production compared to the Dutch bucket system. No significant growth difference was observed between MPE and HFP. In Experiment 2, there was no significant growth difference between ECK and CSF; however, the shoot width, leaf area, and dry weight of lettuce were significantly lower with MPE treatments compared to ECK. Results show that ECK performed similarly or better than synthetic fertilizer for growing lettuce in these container hydroponic systems. The findings of this study indicate that a single organic fertilizer could be used instead of several for organic leafy green production in soilless substrate.

Speakers

Uttara Samarakoon

The Ohio State University

Co-authors

James Altland

USDA-ARS

Joanna Moine

The Ohio State University

Milon Chowdhury

The Ohio State University

Oliver Watson

The Ohio State University

Friday September 27, 2024 11:30am - 11:45am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

12:44pm HST

Growth Chambers and Controlled Environments 8 (CE 8)

Friday September 27, 2024 12:44pm - 2:15pm HST

Nautilus 1

Greenhouse supplemental lighting of lettuce and tomatoes to a target light intensity and daily light integral using dimmable LEDs - Neil Mattson
Hybrid Model for Forecasting Lettuce Yield in Indoor Vertical Farming - MD SHAMIM AHAMED
Rapid Controlled Environmental Propagation of Virus-Indexed Sweetpotato and Field Performance - Phillip Wadl
Development of a pH Management Protocol for Strawberry Mother Plants Grown in Deep Water Culture - Jennifer Boldt
Effect of Nutrient Correction Intervals on Nutrient Imbalance, Plant Growth, Yield, and Fruit Quality of Melon (Cucumis melo L.) in a Closed Hydroponic System - Minju Shin
Adjusting dissolved oxygen in nutrient solution for optimized kale and arugula growth in hydroponics - Kuan Qin
Developing Cardinal Temperatures for Leafy Green Growth and Development Parameters from Constant and Positive Day-Night Temperatures - Sean Tarr
Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite - Sangjun Jeong

Moderator

Neil Mattson

Cornell University

Friday September 27, 2024 12:44pm - 2:15pm HST
Nautilus 1

Oral Sessions, Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

12:45pm HST

CE 8 - Greenhouse supplemental lighting of lettuce and tomatoes to a target light intensity and daily light integral using dimmable LEDs

Friday September 27, 2024 12:45pm - 1:00pm HST

Nautilus 1

A previously developed algorithm controls on/off decisions for greenhouse supplemental light fixtures and retractable shade curtains to achieve a target daily light integral (DLI). The algorithm, termed LASSI (Light and Shade System Implementation) originally used high pressure sodium (HPS) lights with a 1-hour time step to avoid the warm-up time and reduced lifespan of HPS bulbs when they are frequently turned on/off. We have updated the algorithm accounting for dimmability of light emitting diodes (LEDs) for which light intensity can be adjusted in near real-time (RT LASSI). The objective of this study was to compare performance of lettuce ‘Rex’ and Rouxai’ and tomato ‘Sweetelle’ in response to the LASSI algorithm with HPS fixtures vs. RT LASSI with dimmable white LEDs. Experiments were conducted in adjacent greenhouses and DLI setpoints were 17 mol·m-2·d-1 for lettuce and 25 mol·m-2·d-1 for tomatoes. RT LASSI greenhouses had white LEDs (TSR Grow TG-600 HVR) and LASSI greenhouses had HPS fixtures (PL Light 1000 W). For treatments with RT LASSI, when supplemental lighting was called for, LED treatments were adjusted to complement sunlight to achieve a target instantaneous light intensity of 300 and 400 µmol·m-2·d-1 for lettuce and tomatoes, respective, averaged over a 10 minute interval. For tomatoes a minimum 4-hour dark period was imposed while for lettuce, supplemental lighting could occur anytime within the 24-hr period. For lettuce there were three replicate, 35 d crop cycles and for tomatoes plants received 15 weeks of treatment after reaching the fruiting stage with no replication. Both algorithms controlled DLI close to target. For lettuce, LASSI with HPS led to larger plant height and volume and increased fresh weight (but not dry weight) vs. RT LASSI with LED. For tomatoes, RT-LASSI with LED led to about a 30% greater tomato yield vs. LASSI with HPS. Increased yield was associated with increased fruit size but not increased fruit or truss number. Brix of HPS grown fruit was higher than LED fruit. While air temperature was very similar between both treatments, HPS fixtures may have increased plant temperature of LED. More research is needed to determine if plant impacts were due to type of lighting fixture and associated plant temperature and light spectrum or to the control algorithm itself (spreading supplemental lighting across greater hours per day).

Co-authors

Nicholas Kaczmar

Cornell University

Timothy Shelford

Cornell University

Friday September 27, 2024 12:45pm - 1:00pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:00pm HST

CE 8 - Hybrid Model for Forecasting Lettuce Yield in Indoor Vertical Farming

Friday September 27, 2024 1:00pm - 1:15pm HST

Nautilus 1

The surging demand for sustainable agriculture has accelerated the adoption of indoor vertical farming as a pragmatic solution. Lettuce, a cornerstone crop in this context, assumes significant importance. Accurate forecasting of lettuce yield is indispensable for optimizing resource allocation and ensuring a steady supply. Most existing models used either environmental data or images to predict yield predictions, which could be erroneous for complex systems. This study aims to improve the accuracy of yield prediction in indoor farming settings with a hybrid model. First, we applied the feedforward neural network and random forest models for yield prediction, leveraging data from environmental sensors, cultivation practices, and historical yield records. Then, a convolutional neural network model is tailored to forecast yield using image data captured by RGBD cameras. Based on our results, we found reasonable accuracy in terms of RMSE and MAE, which range between 10-25 gm and 28-49 g, respectively. By amalgamating these diverse models, we aim to elevate yield prediction accuracy. It’s hypothesized that the proposed hybrid model would outperform individual approaches, offering invaluable insights for indoor vertical farming operations decision-making.

Speakers

MD SHAMIM AHAMED

University of California, Davis

Friday September 27, 2024 1:00pm - 1:15pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:15pm HST

CE 8 - Rapid Controlled Environment Propagation of Virus-Indexed Sweetpotato and Field Performance

Friday September 27, 2024 1:15pm - 1:30pm HST

Nautilus 1

Sweetpotato (Ipomoea batatas) production relies on clonal propagation of either sprouted storage roots grown in plant beds or from cuttings from greenhouse grown plants. In the USA, the Sweetpotato National Clean Plant Network Centers (SP-NCPN) provide virus-free planting stock of important cultivars for sweetpotato growers. However, most of the virus-indexed materials can be rapidly re-infected by one or more viruses within one growing season via insect vectors. Production of enough virus-indexed propagules is a major challenge and annually shortages exist. We have developed a controlled environment agriculture (CEA) technology that provides rapid propagation of virus-indexed propagules from SP-NCPN foundation stocks within 6 – 12 months. From a single virus-indexed in vitro plantlet, 500 rooted plants were obtained in 3 months compared to 3 plants via tissue culture micropropagation. Within 3 months the 500 rooted plants generated about 250,000 plants. Field performance (establishment and yield) of slips and rooted transplants from the CEA technology were compared with traditional plant bed derived slips. No significant differences were detected for establishment and canner and cull yield, whereas differences were found for total, marketable, jumbo, and US no. 1 yield. Our results offer a potential solution for providing growers a readily available source of virus-indexed propagule source that are comparable to field grown slips.

Speakers

Phillip Wadl

USDA, ARS, U.S. Vegetable Laboratory

Co-authors

Augustine Gubba

University of KwaZulu Natal

Bazgha Zia

USDA, ARS, U.S. Vegetable Laboratory

Christie Almeyda

North Carolina State University

Christopher Clark

Louisiana State University

John Coffey

USDA, ARS, U.S. Vegetable Laboratory

Joni McGuire

USDA, ARS, U.S. Vegetable Laboratory

Kai-Shu Ling

USDA, ARS, U.S. Vegetable Laboratory

Matthew Cutulle

Clemson

Friday September 27, 2024 1:15pm - 1:30pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:30pm HST

CE 8 - Development of a pH Management Protocol for Strawberry Mother Plants Grown in Deep Water Culture

Friday September 27, 2024 1:30pm - 1:45pm HST

Nautilus 1

Maintaining a target pH range is important for root zone management and overall plant growth and quality. Commercial soilless substrates often contain liming amendments to increase initial substrate pH to between 5.5 and 6.2. Hydroponic nutrient solutions are less-well buffered than soilless substrates and can experience pH drift in the absence of frequent monitoring and adjustment. Hydroponic deep water culture (DWC) was explored for strawberry (Fragaria × ananassa) research studies, to more-easily collect root growth parameters and root samples for elemental analysis, compared to soilless substrate culture. However, an effective strategy for pH management needed to be developed. The objective of this study was to develop a protocol for growing strawberry mother plants hydroponically. First, three hydroponic systems (drip-irrigated coarse perlite, drip-irrigated sand, and DWC) were compared to a peat-based soilless substrate control. Plants received a modified strawberry nutrient solution (Yamazaki) at a nitrogen (N) concentration of 100 mg·L-1. Plants grew similarly across the four growing systems. Deep water culture provided the easiest access to clean roots; however, root zone pH decreased

Speakers

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Co-authors

Erin Yafuso

United States Department of Agriculture

Friday September 27, 2024 1:30pm - 1:45pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:45pm HST

CE 8 - Adjusting dissolved oxygen in nutrient solution for optimized kale and arugula growth in hydroponics

Friday September 27, 2024 1:45pm - 2:00pm HST

Nautilus 1

Dissolved oxygen (DO) level in hydroponic solution is an important factor affecting plant root development and water and nutrient uptake. However, precisely controlling the DO level in hydroponics has always been difficult due to the direct linkage of solution temperature and oxygen concentrations, especially under different aeration methods. Besides potentially controlling solution temperature, using liquid oxygen fertilization such as hydrogen peroxide (H2O2) has been shown to burst increase DO concentration in the solution, and ozonation, which is a sanitization treatment, has the potential to adjust DO level by supplying oxygen in nutrient solution. Our objective was to evaluate the effects of different DO levels and oxygenation strategies in a hydroponic system for the optimal growth of kale (Brassica oleracea) and arugula (Eruca vesicaria). In this study, we used ozone generators and hydrogen peroxide (H2O2) as a DO enrichment method in addition to the air pump-based aeration system to test the effects of different DO levels – low, medium, high as 6, 9, 12 mg/L, respectively – on kale ‘KX-1’ and ‘Red Russian’, and arugula ‘Astro’ and ‘Esmee’ grown in a deep water culture system. Treatment without using ozone generators or H2O2 was assigned as control. The study was arranged as a completely randomized design with three replications. DO and temperature probes were connected to a datalogger to trigger ozone generators and H2O2 injection using a relay once the DO levels were below the set thresholds. Weekly measurements were taken for plant height, leaf and anthocyanin chlorophyll content. The final harvest additionally measured leaf area, shoot and root biomass the leaf soluble solids content, titratable acidity, and leaf nutrient concentration. Plants grown under a high DO level had a higher root-to-shoot ratio, but the overall higher plant yield was achieved under the medium DO level. This system demonstrated that precise DO level control could be achieved using a sensor-based system.

Speakers

Kuan Qin

University of Georgia

Friday September 27, 2024 1:45pm - 2:00pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

2:00pm HST

CE 8 - Developing Cardinal Temperatures for Leafy Green Growth and Development Parameters from Constant and Positive Day-Night Temperatures

Friday September 27, 2024 2:00pm - 2:15pm HST

Nautilus 1

In the evolving landscape of controlled environment agriculture (CEA), precise temperature management remains a pivotal factor in enhancing the growth, development, productivity, and quality of high-value leafy greens. Our research identifies the cardinal temperatures — base (Tb), optimum (Topt), and maximum (Tmax) — for red-leaf and green butterhead lettuce (Lactuca sativa), arugula (Eruca sativa), and kale (Brassica oleracea), comparing how both constant mean daily temperature (MDT) within a greenhouse and positive day-night temperature differences (DIF) in a growth chamber influence plant growth and development. In the greenhouse, we had a constant MDT of 8, 13, 18, 23, 28, and 33 °C under a photosynthetic photon flux density (PPFD) of 220 µmol∙m‒2∙s‒1 for 12 h∙d–1, while in the growth chamber we targeted the same MDTs with air day/night (12 h/12 h) set points of 11/5 °C, 16/10 °C, 21/15 °C, 26/20 °C, 31/25 °C, or 36/30 °C under a PPFD of 300 µmol∙m‒2∙s‒1. Both arugula and kale had greater biomass accumulation at lower Tb and Topt compared to lettuce, suggesting a propensity for growth under a cooler MDT. Specifically, the Topt for fresh mass accumulation was found to be at 24.7 °C for arugula, 22.9 °C for kale, and higher for lettuce cultivars 'Rex' and 'Rouxaï RZ' at 24.7 and 26.2 °C, respectively. We found that DIF exerted minimal influence on these crops, emphasizing the critical role of MDT in influencing their developmental outcomes. Additionally, our research provides insight into the impact of temperature on various physiological and morphological parameters, such as leaf unfolding rate, biomass accumulation, and susceptibility to physiological disorders such as bolting or tipburn. This study underscores the importance of precise temperature management in CEA, offering guidance for producers seeking to optimize energy use while maximizing crop yield and quality.

Speakers

SEAN TARR

Michigan State University

Co-authors

Roberto Lopez

Michigan State University

Friday September 27, 2024 2:00pm - 2:15pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

2:29pm HST

Growth Chambers and Controlled Environments 9 (CE 9)

Friday September 27, 2024 2:29pm - 4:00pm HST

Nautilus 1

Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite - Sangjun Jeong
Lighting Around the Clock: Greenhouse Production with 24h Lighting - Jason Lanoue
Explore a Cost-friendly Way for Plant Nitrogen Stress Identification - Ping Yu
Optimization of Irrigation Based on Substrate Type for Tomato Production in the Dutch Bucket Hydroponic System - Milon Chowdhury
The Secondary Metabolite Production and Growth Responses of Cannabis to Thigmomorphogenesis in a Controlled Environment - Jose Franco Da Cunha Leme Filho
Simulated Climate-change-related Environmental Stressors Can Alter the Yield and Metabolomics of Tomato - Marlo Vandiver

Moderator

Ping Yu

University of Georgia

Friday September 27, 2024 2:29pm - 4:00pm HST
Nautilus 1

Oral Sessions, Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

2:30pm HST

CE 9 - Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite

Friday September 27, 2024 2:30pm - 2:45pm HST

Nautilus 1

Phytochromes (PHYs) play a dual role in sensing light spectral quality and temperature. PHYs can interconvert between their active and inactive forms upon absorption of red and far-red light (Photoconversion). In addition, the active form can be converted to the inactive form in a temperature-dependent manner (Thermal Reversion). Our recent research found that while far-red (FR; 700-800 nm) light promoted leaf expansion and biomass of lettuce (Lactuca sativa) ‘Rex’ under cooler temperatures (20-24 °C), it reduced plant biomass and leaf area under warm temperature (28 °C). Considering that PHY activity would be driven mainly by photoconversion, not thermal reversion, under higher light intensity (HL), we hypothesized that the magnitude of the interaction between FR light and temperature on plant growth and morphology decreases with increasing light intensity. Lettuce ‘Rex’ was grown under three temperature regimes (20, 24, and 28 oC) x two spectral treatments [0 and 20% of FR light in total photon flux density (TPFD; 400-800 nm)] x two light intensities [150 (lower light intensity; LL) and 300 (HL) μmol·m-2·s- 1 of TPFD]. Our results showed that the effects of FR light on leaf expansion and stem elongation depended on temperature under LL. Specifically, FR light significantly promotes leaf expansion under cooler temperatures (20 oC), while decreasing total leaf area under warmer temperatures (24 and 28 oC). However, the magnitude of the interactive effects between FR light and temperature on plant morphology decreased under HL, leading to a consistent increase in total leaf area by FR light under HL. Similarly, FR light promoted plant growth under HL regardless of temperature, while reducing plant biomass under warm temperature under LL. Crop yield was primarily dependent on photon capture rather than photosynthetic efficiency per unit leaf area. FR light generally decreased the production of secondary metabolites (e.g., phenolics and flavonoids), while warm temperature and HL treatments increased the production of secondary metabolites. We concluded that the interactive effects between FR light and temperature on plant growth and morphology are further dependent on light intensity. The combination of FR light, warm temperature, and HL could maximize crop yield without reducing nutritional quality in terms of antioxidant capacity.

Speakers

Sangjun Jeong

Texas A

Co-authors

Genhua Niu

Texas A

Shuyang Zhen

Texas A

Friday September 27, 2024 2:30pm - 2:45pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

2:45pm HST

CE 9 - Lighting Around the Clock: Greenhouse Production with 24h Lighting

Friday September 27, 2024 2:45pm - 3:00pm HST

Nautilus 1

Photoperiod extension in controlled environment agriculture - including the use of 24h continuous light - can be used to reduce light fixture and electricity costs in regions with lower night electricity rates. However, many plant species develop photoperiodic injury characterized by leaf chlorosis and yield reduction at a critical species-specific photoperiod threshold. Here we will discuss the response of different plant species to continuous lighting strategies. We will first challenge the conventional notion that dark adapted chlorophyll fluorescence (Fv/Fm) measurements are the most appropriate when assessing photoperiodic injury. We provide evidence that light adapted (φPSII) measurements allow for a more in-depth understanding of the light capture process at photosystem II. Through RNA-sequencing in tomato, we determined that the use of a dynamic 24h lighting treatment (i.e., red light during the day and blue light during the night) lead to normal gene expression of chlorophyll a/b binding (CAB) proteins. However when tomato plants were grown under a static continuous lighting strategy (i.e., red blue lighting for 24h) at the same daily light integral, gene expression of CAB proteins were drastically reduced, resulting in chlorosis and yield reduction. In comparison to tomatoes, cucumbers tend to be more tolerant to long photoperiods and therefore continuous lighting can have an immediate impact in commercial production. Initial results in cucumbers show that a continuous lighting strategy can decrease the lighting electricity costs by 26% and greenhouse gas emissions by 38.9% per unit of produce compared to a 16h control treatment. Using the knowledge gained throughout our studies, we propose a lighting strategy which gamifies the electricity market to further reduce costs and greenhouse gas emissions.

Speakers

Jason Lanoue

Agriculture

Co-authors

Quade Digweed

Agriculture

Xiuming Hao

Agriculture

Friday September 27, 2024 2:45pm - 3:00pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:00pm HST

CE 9 - Explore a Cost-friendly Way for Plant Nitrogen Stress Identification

Friday September 27, 2024 3:00pm - 3:15pm HST

Nautilus 1

Plant stress can cause economic loss for plant production and is hard and expensive to identify at times. Thus, a greenhouse experiment was conducted to find an easy and cost-friendly way to identify plant stress, set up thresholds and values for the initiation of plant nitrogen stresses. Four different crops (basil, pepper, marigold, and sage) were included and treated with five different nitrogen levels (0%, 25%, 50%, 75%, and 100%). Plant height, width and leave greenless (indicated by SPAD) were measured weekly. Pictures were taken weekly. Software Image J was used to process pictures and R was used for data analysis. We found that plants with higher nitrogen treatments (75%-100%) all grow better and have higher SPAD than other treatments, except for bail. Also, RGB value could indicate plant nitrogen status with high accuracy. Plants become nitrogen stressed when SPAD falls to 25. Red and green values in RGB have negative correlations directly with SPAD and indirectly with nitrogen stress status. When the R and G values are higher than 150 and 185, respectively, we can safely predict that the plant is nitrogen stressed. In conclusion, using RBG value can be a cost-friendly way for plant stress identification.

Speakers

Ping Yu

University of Georgia

Co-authors

Kuan Qin

University of Georgia

Friday September 27, 2024 3:00pm - 3:15pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:15pm HST

CE 9 - Optimization of Irrigation Based on Substrate Type for Tomato Production in the Dutch Bucket Hydroponic System

Friday September 27, 2024 3:15pm - 3:30pm HST

Nautilus 1

Dutch bucket hydroponic systems are used for high-wire crop production such as tomatoes, cucumbers, or peppers, and are typically filled with perlite as a substrate. Through past research, our group identified pine bark and wood fiber as sustainable alternative substrates for high-wire tomato production. Typically, greenhouse tomato growers utilize leachate-based or timed irrigation; however, the use of a water content sensor could precisely identify the irrigation set-point for different substrates, potentially saving water and fertilizers. This study aimed to optimize the irrigation rate for greenhouse tomato ('Favorita F1') production in the Dutch bucket hydroponic system using a soil water content sensor. Three types of substrates (perlite, pine bark, and wood fiber-coir mix (60:40)) and four different gravimetric water contents (100%, 120%, 140%, and 160%) were considered. The experiment was conducted with three replications in a completely randomized design, with the irrigation treatments under the perlite substrate serving as the control. Physical parameters, such as the number of leaves and plant height, were significantly higher in the wood fiber-coir mix and pine bark at 160% irrigation, and lowest under perlite at 100% water content. However, there was no significant difference among the treatments for the number of flower (fruit) clusters. The plant leaf area measurements indicated better vegetative growth with wood fiber-coir mix at 160% water content, whereas pine bark at 160% water content resulted in a higher yield and better fruit quality. In contrast, phytochemicals such as Brix, vitamin C, titratable acidity, lycopene, beta-carotene, and phenolic compounds were significantly higher in the organic substrates (pine bark and wood fiber) with low water content (100% to 120%) and lower in perlite with high water content (140% to 160%). The highest and lowest concentrations of phytochemicals varied between 13% to 67%. There was no significant difference among the treatments (substrates and water contents) in terms of tissue mineral analysis. In general, plants grown in wood fiber-coir mix treatments required 28% and 51% less irrigation compared to those in pine bark and perlite treatments, respectively. Plants grown in organic substrates require less water, and the yield quantity and quality are either similar to or higher than those in perlite. Out of the organic substrates, wood fiber-coir mix can be used in Dutch bucket systems to conserve water and nutrients, enhancing yield quantity and quality, and thereby achieving environmental sustainability.

Speakers

Milon Chowdhury

The Ohio State University

Co-authors

James Altland

USDA-ARS

Joanna Moine

The Ohio State University

Uttara Samarakoon

The Ohio State University

Friday September 27, 2024 3:15pm - 3:30pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:30pm HST

CE 9 - The Secondary Metabolite Production and Growth Responses of Cannabis to Thigmomorphogenesis in a Controlled Environment

Friday September 27, 2024 3:30pm - 3:45pm HST

Nautilus 1

As legalization continues to change the cannabis industry, we see an influx of creative innovation, funding, and research as more entities enter the field. The two innovative growing management investigated in this study were Mechanical Vibration Training (MVT) and High Stress Training (HST). MVT was carried out using a grid exposing the plants to 200 Hz vibration, and HST is a practice that involves damaging the vascular bundles, pith, and cortex of the main stem while leaving the epidermis intact. MVT is a newer technique still in development, as Thigmo-priming has been shown to change plant morphology and chemistry and even increase the speed and magnitude of future stress responses. Many industry leaders claim that the advantages of using HST include higher canopy, increased biomass and cannabinoid concentrations, and more effective IPM strategies. However, studies validating these claims are still being determined. This study aims to compare each growing management under the overall category of Thigmomorphogenesis or mechanostimulation against control (no artificial mechanical stimulation) and tease out any synergism between the treatments. We hypothesize that applying mechanostimulation to cannabis plants will enhance their growth and increase secondary metabolite production. The environment-controlled growth units housed the treatments consisted of 1-Control, 2-MVT, 3-HST, and 4-MVT HST. Each growth unit contained five-gallon fabric pots with a single Suver Haze plant. An amended coco coir substrate was used with a water-soluble nutrient solution, and optimal growing conditions, including lighting, were maintained equally in all environment-controlled growth units. Weekly plant parameters included stem diameter, plant height, NDVI, chlorophyll concentration, and photosynthetic efficiency. After-harvest parameters included above/below ground biomass, yield mass, bucked biomass, trichome density, and cannabinoid levels. Morphological and numerical differences between treatments indicated the potential for a shorter, more efficient growth cycle with higher cannabinoid levels. Further testing is currently underway.

Speakers

Jose Franco Da Cunha Leme Filho

Southern Illinois University

Co-authors

Aldwin Anterola

Southern Illinois University

Dila Ozev

Southern Illinois University

Gorman Saunders

Southern Illinois University

Jennifer Weber

Southern Illinois University

Karla Gage

Southern Illinois University

Shiksha Sharma

Southern Illinois University

Friday September 27, 2024 3:30pm - 3:45pm HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:45pm HST

CE 9 - Simulated Climate-change-related Environmental Stressors Can Alter the Yield and Metabolomics of Tomato

Friday September 27, 2024 3:45pm - 4:00pm HST

Nautilus 1

Climate change challenges all aspects of food production, including standard greenhouse products, such as tomatoes. The cause of climate change can be directly attributed to the rise in carbon dioxide (CO2) levels, leading to increased temperatures and drought severity. Tomatoes are the most produced fruit crop globally, and in addition to their economic benefits contain several vitamins and minerals essential for human health. The objective of this study was to assess the multi-variable effects of simulated climate change on tomato plants by investigating the combination of elevated CO2 (800 ppm vs 400 ppm), increased temperature (28℃ vs 21℃), and water deficit stress (20% decrease from control) across three development stages: juvenile, anthesis, and fully mature tomato. ‘Sweet ‘N’ Neat Scarlet’ tomatoes (Solanum lycopersicum) were grown in four plant growth chambers in a 2 x 2 x 2 factorial design with four replications. Quality parameters included photosynthetic efficiency, growth index, dry weight, flower number, fruit number, and fruit size. Inductively coupled plasma mass spectrometry (ICP-MS) and oxygen radical absorbance capacity (ORAC) analyses were measured at each of the three stages when applicable. Preliminary data suggests that higher temperatures and CO2 increase (p

Speakers

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE