ASHS 2024 Conference

Watermelon Rootstock Variety Trial to Understand the Impacts of Grafting on Watermelon Yield and Fruit Quality - Fayrouz Buojaylah
Effect of Biofungicides Containing Trichoderma and Grafting on Watermelon Productivity and Plant Health - Fayrouz Buojaylah
Canary Melons Cultigen Yield and Quality Evaluations in North Carolina, 2023 - Jonathan Schultheis
Watermelon Cultigen Yield Response to Fusarium oxysporum f. sp. niveum Incidence in North and South Carolina, USA - Stuart Michel
Effect of Biostimulants on Field Grown Watermelon (Citrullus lanatus) under Deficit Irrigation and Fertility. - Evan Christensen
Development of the winter artichoke production system in a subtropical climate - Shinsuke Agehara
Globe Artichokes - Variety Trials for Florida Production and Marketing Evaluations - Evelyn Fletcher

In California, watermelon grafting has been gaining tremendous popularity over other graft-eligible vegetable commodities especially among large-acreage growers. To maintain viability and continued popularity of grafted watermelons in California, we conducted a watermelon rootstock variety trial in 2023 to evaluate the impact of different types of locally popular rootstocks on watermelon yield and quality. Seven watermelon rootstocks, grouped into three distinct types: Interspecific hybrid squash (Cucurbita maxima x Cucurbita moschata), Citron (Citrullus amarus), and Bottled gourd (Lagenaria siceraria), were grafted with a 45-ct field scion, ‘Warrior’ by a commercial greenhouse located in Mills River, NC. All grafted and non-grafted seedlings were then mechanically transplanted into a commercial field near Modesto, CA on 19 April 2023. The trial was arranged as a randomized complete block design with four replications for each treatment. Each plot was 24 m long and contained 13 triploid plants, either grafted or not, alongside four grafted or non-grafted pollenizers. Four harvests were conducted from 25 July to 17 Oct with the help of farm crew. Total yields at each harvest and fruit quality from the first harvest were recorded and compared among rootstock-scion combinations. For quality assessment, fruit length and width were measured with a yardstick. Sugar content (ºBrix) was measured by scooping the central flesh of each halved fruit using a portable reflectometer. Flesh firmness was evaluated using a fruit penetrometer, with measurements taken at spots located one-third and two-thirds of the distance from the blossom end after halving the melon. Rind thickness at the blossom and stem ends were measured using a digital caliper. The overall impact of grafting resulted in an average increase of total yield by 51.5% compared to the non-grafted control (54.7 vs. 36.1 tons per acre) with the most significant difference occurred at the second harvest (27.0 vs. 14.8 tons per acre). Differences of fruit quality between grafted and non-grafted watermelons were primarily observed for fruit firmness. The significant increase of firmness (4.9 vs. 3.4 kg.cm-2) for grafted fruit was also confirmed based on the results of taste sensory evaluation. Slight increases of fruit width and stem end rind thickness after grafting were also found. No changes of ºBrix after grafting were detected. Overall, grafting has proven to be a reliable method for enhancing watermelon yield and maintaining fruit quality in California. Continuous needs assessment will be performed to monitor any pressing issues of watermelon grafting in California.

The goal of the project is to evaluate the potential of reducing chemical fumigation in California's watermelon production using grafting and Trichoderma-based biofungicide. Two field experiments in 2022 and 2023 were implemented within commercial watermelon fields in Stockton and Modesto, CA. Each trial included three rootstocks (Cobalt, Flexifort, and RS841) grafted onto a 45-ct scion (Summer Breeze). Two Trichoderma-containing products were applied to the grafted and nongrafted seedlings through tray soaking at one day before transplanting or field chemigation at 30 and 62 days after transplanting (DAT). The application rates for soaking and chemigation were 45 g.75 L-1 of water and 2.2 kg.ha-1, respectively. All seedlings were mechanically transplanted during mid-May of both years into a split-split plot design with the Trichoderma product as the main factor and application method as the sub-plot. All treatments were replicated four times. Each treatment row was 18.6 m long and contained ten grafted or nongrafted triploids and three grafted or nongrafted pollenizers. Vine health was visually assessed three times for symptoms associated with soil-borne fungal pathogens. Canopy coverage was measured starting at 22 DAT in 2022 and 40 DAT in 2023 and thereafter at an approximate interval of two weeks for a total of six measurements. Harvest was conducted three times in 2022 and twice in 2023 to analyze yield and quality differences among treatments. Runner and root samples were taken amid the harvest and shipped to the UC Davis Fungal Pathology Lab for further identification. Results indicated that the Trichoderma-containing bio-fungicides were not as effective as grafting on preventing vine decline and maintaining canopy coverage in both trials. The synergistic effects of grafting and Trichoderma inoculation provided some but limited benefits to plant health compared to the single factor of grafting. The overall influence of biofungicides on yield was also less notable than that of grafting regardless of application method. For fruit quality, grafting dominated the impacts over biofungicides on fruit firmness and rind thickness in both trials. Charcoal rot (Macrophomina phaseolina) with other putative co-infestations of Fusarium pathogens were diagnosed from nongrafted inoculation-free plots in 2022 while no significant soil-borne diseases were identified from 2023. Overall, grafting with multi-pathogen resistant rootstocks prove to be a reliable method for enhancing watermelon yield while maintaining crop health. More work is still needed to further explore the optimal application protocols tailored to grower’s farming system to maximize the effects of biofungicide.

Canary melons, Cucumis melo var. inodorus, are grown in the United States, with most acreage produced in California and Arizona. There is very limited production acreage in the southeastern United States, including North Carolina. No statistics are gathered by USDA on canary melons as this type of melon is truly a specialty melon. The goal of this study was to determine how well adapted canary melon cultigens are with respect to yields and quality when grown in North Carolina and to gauge the possibilities of producing this crop as a commercial option in the state. Fourteen cultigens were evaluated from eight different seed companies for yield and size over 16 harvests, flesh firmness and sweetness, and shape and rind characteristics. Statistical design was a randomized complete block with four replications and mean separation across measures was conducted using a LSD test at the P

Fusarium wilt of watermelon, caused by the soilborne pathogen Fusarium oxysporum f. sp. niveum (FON), is a major disease impacting the watermelon industry. FON can severely reduce yields and is easily dispersed. Cultivar resistance is a desired control strategy due to high fungicide and grafting costs. In 2021 and 2022, triploid watermelon cultivars were evaluated at two locations (Clayton, NC and Charleston, SC) for their tolerance to FON. Eight common cultivars were evaluated for disease incidence and yield at both locations in both years. In 2022, two unreleased cultigens were also evaluated at both locations. All studies used a randomized complete block design with four replications. ‘Fascination’ grafted to ‘Carolina Strongback’ rootstock was included as a control each year. Disease incidence was measured every week starting three weeks after transplanting and until the first harvest at each location. Fruit weights and counts were taken to measure yield. In 2021, ‘Fascination’ had the lowest disease incidence at 75% in NC and ‘Embasy’ had the lowest incidence at 15% in SC. ‘Joy Ride’ had 100% incidence in NC and ‘Shoreline’ had the highest incidence in SC at 68%. Yields correlated with disease incidence with ‘Fascination’ having the highest yield of the ungrafted treatments in NC with 17,878 lb/ac (pounds per acre) and ‘Embasy’ with 22,687 lb/ac in SC. ‘Shoreline’ was the lowest yielding at both locations with 6,556 lb/ac in NC and 5,376 lb/ac in SC. The grafted ‘Fascination’ treatment had the lowest disease incidence and the highest yield at both locations in 2021. In 2022, the unreleased cultigen HMC633802 had the lowest disease incidence at both locations with 50% in NC and 51% in SC. Of the eight common cultivars, Fascination had the lowest incidence in NC at 83% and El Capitan had the lowest in SC at 52%. ‘Shoreline’ had the highest incidence at both locations with 100% in NC and 94% in SC. Yields correlated with disease incidence. Unreleased cultigen HMC633800 had the highest yield of the ungrafted treatments in NC with 15,575 lb/ac and Powerhouse had the highest yield in SC with 27,243 lb/ac. The grafted ‘Fascination’ treatment had the lowest incidence and highest yield at both locations in 2022. The cultigens we evaluated provided minimal tolerance to FON in both years.

The impacts of climate change and drought threaten water supplies crucial for watermelon production. Rising fertilizer costs and off-site effects also pose problems for the sustainability of watermelon production. Biostimulants shown promise in helping plants maintain production under deficit irrigation conditions and may offset fertility addition through ecosystem services and stimulatory effects. In this study two watermelon cultivars (Crimson Sweet and Fascination) were treated with three biostimulant products (Mighty Mycorrhizae, Spectrum DS, and Continuum) and then subjected to reduced fertility (67% of recommended rate) and irrigation (75% evapotranspiration). Raised beds covered in plastic mulch were used with rows spaced 1.83 meters apart and plants 0.61 meters apart within rows. Growth metrics and stages were recorded and compared among treatments. Watermelon fruits were harvested at maturity over a one-week period and yield was compared. The final biomass was measured after harvest. Statistical analysis is ongoing, and a second year of this field trial will be completed in August 2024, allowing for final conclusions to be drawn.

Artichoke (Cynara cardunculus var. scolymus) belongs to the sunflower family and is cultivated for its flower buds. Being adapted to Mediterranean climates, artichoke plants require adequate winter chilling for flower bud induction and yet is susceptible to freeze damage. Because of these climatic requirements, nearly 100% of artichoke production in the United States currently comes from California. Insufficient winter chilling is among the major environmental constraints for artichoke production in subtropical and tropical climates. We started this study in 2015 with the goal of developing artichoke as a new winter crop in Florida. First, we developed a protocol for artificial flower bud induction using a plant hormone, gibberellic acid (GA3). With the optimum rate and timing, GA3 application is highly effective in inducing bud formation, irrespective of winter chilling. Second, we evaluated eight cultivars based on earliness of bud formation, yield, and bud quality. ‘Imperial Star’ and ‘Green Queen’ were selected as the most promising cultivars in Florida, with the maximum yields of 17.3 and 11.8 t ha–1, respectively. The current artichoke production guide provides recommendations on GA3 application, cultivars, planting configurations, plastic mulch, and basic pest management. In 2023, artichoke was grown on about 12 hectares in Florida using the production guide we developed. We are currently testing additional hybrid cultivars and assessing nutritional values and postharvest quality to enhance the viability of artichoke as Florida’s new winter crop.

The globe artichoke (Cynara cardunculus) is a large thistle crop of the Asteraceae family, native to the Mediterranean. Globe artichokes are a large, leafy plant, with edible component as an immature flower bud. With production dominated by California, Florida can provide a new commodity for southeastern growers while reducing our carbon footprint. Globe artichokes have not been a traditional crop in the state of Florida, even as a garden variety. This study demonstrates the need to focus on varieties for the subtropics. We evaluated the best performing artichoke variety in addition to the retail favorite by curb appeal. Within a farmer's market survey, more than 80% of shoppers voted for 'Green Queen' amongst five other varieties (Imperial Star, Green Globe Improved, etc.). It also represented the highest yielding, at 12,707 lbs/acre, followed by 'Imperial Star' at 11,484 lbs/acre. An artichoke was valued at $4 each globe, while the flower was $5 per stem during the Mother's Day market. The demand continues from chefs and newly transplanted retail shoppers.

Whether marketing to a horticulture consumer or educating them, understanding motivations is crucial. In 2023, a nationwide survey of gardening consumers conducted by a regional team of horticulture researchers provided key insights into how backgrounds and experiences impacted motivations of horticulture consumers. Cluster analysis performed on the data provides the ability to group consumers in terms of their interest and spending to enable more tailored education or marketing efforts. This workshop will investigate the key characteristics of those ten groups according to demographics, experience, motivation, and spending and integrate the experience and insight of attendees to best utilize the survey information. The goal of this highly interactive workshop will be to develop representative avatars and actionable outreach and marketing ideas that can be integrated into Extension programming as well as used to equip garden centers and horticultural businesses to be intentional and effective in reaching, educating, and retaining these new consumers. Horticulture professionals with research, Extension, teaching, and/or business focuses are all invited to attend and aid in honing audience descriptions based on current data. This session will set the stage for developing more tools to support Consumer Horticulture outreach and marketing to current and future audiences.

This workshop is grounded in current research findings and will focus on turning findings into tools that can be used by a wide range of ASHS professionals to reach current and future audiences.

Engage a diverse set of Horticulture professionals and define up to 10 core target audiences in today's horticultural market whether that is a retail business, classroom, or other outreach program.

This session will have minimal large-group presentation time. Six team leaders will break the audience into small groups based on interests and lead them through a series of prompts to assign descriptors to different audiences as defined by recent survey data. Participants will aid in coding different types of audience members, report out to the larger group, and group work will be cross-checked to determine key target audiences and best methods of communication with each.

Coordinator(s)

• Kristine Lang, South Dakota State University, Agronomy, Horticulture, and Plant Science, Brookings, South Dakota, United States

Moderator(s)

• Gerald Burgner, Texas A&M University, United States
• Natalie Bumgarner, University of Tennessee, Plant Sciences, Knoxville, TN, United States
• Sheri Dorn, University of Georgia, United States
• Heather Kirk Ballard, Louisiana State University, United States
• Julie Campbell, University of Georgia, Horticulture, Athens, Georgia, United States

Assessing Grapefruit Responses to Different Irrigation Rates for Managing Salinity Water Under Greenhouse-Controlled Conditions - Neus Alcon Bou
Irrigation trials examine yield, water productivity, and nitrogen uptake of summer cauliflower - Michael Cahn
Growth Morphology as Indicators of Salt Water Tolerance in Watermelon Cultivars - Azeezahmed Shaik
Assessment of Salinity Tolerance in Cucumber Cultivars Using NFT System - Azeezahmed Shaik
Influence Of Deficit Irrigation And Biochar Application On Soil Water Depletion, Roots Distribution, And Water Use Efficiency Of Cucumber - Sukhbir Singh
Assessing Resource-use Efficiency Affected by Irrigation Management Practices in Processing Onion Production - Ali Montazar
Assessing Drip Irrigation as an Alternative to Micro-sprinklers During Strawberry Establishment in Southern California - Andre Biscaro

Coastal agriculture frequently relies on surface water for irrigation. However, in Florida, surface water availability can become limited during the dry season, leading growers to switch to groundwater. Groundwater in coastal areas often contains high salt concentrations which can negatively affect crop production. Citrus species, one of the most cultivated crops in Florida, are sensitive to salt stress. Among other strategies, irrigation management is used to mitigate salinity buildup in soil by leaching salts away from the root zone. Increased irrigation rates with water sources in the ‘slight’ to ‘moderate’ range of salinity (0.7 to 3 dS/m) have been shown to reduce salt accumulation in the soil without affecting production. However, when the water has high salinity concentrations (>3 dS/m), increasing the irrigation rate beyond 125%-130% of the crop evapotranspiration (ETc) is not sustainable due to the high-water usage. Conversely, a limited volume of water applied for leaching the salts can exacerbate the accumulation. In coastal Florida, where often only high salinity water is available during the dry season, evaluating short-term strategies to maintain crop production is crucial. The objective is to understand how irrigation water with high salinity concentrations and different irrigation rates impact plant performance and soil salinity accumulation. In this study, one-year-old ‘Ruby Red’ grapefruit trees grafted on ‘US-942’ rootstock were planted in a weighing lysimeter phenotyping platform (“Plant Array”) under greenhouse-controlled conditions. Irrigation water with high salinity concentration (5 dS/m) was precisely applied at three different irrigation rates: 75% (deficit), 100% (regular), and 125% (excessive) of the ETc. A control treatment with water at a low salinity concentration (0.3 dS/m) was applied at 100% ETc for comparison. Transpiration, plant net weight, soil moisture and soil electrical conductivity (EC) were recorded daily. Bulk leaf water potential, osmotic potential, and dark-adapted chlorophyll fluorescence were measured at the beginning and at the end of the experiment. Results showed that ETc and net weight decreased for those plants irrigated with high salinity concentration compared to the control. Salt EC was higher for those trees irrigated with 75% ETc under high salinity concentration resulting in the lowest ETc rates. Plants irrigated with 100% and 125% ETc rates showed similar results, likely due to decreasing transpiration of trees upon high salinity treatment application. Different plant performance under different irrigation rates emphasized the need of evaluating irrigation strategies in mitigating salt stress in citrus, particularly in region with limited water resources.

Replicated irrigation trials were performed on cauliflower (Brassica oleracea var. botrytis cv. Symphony) in California’s Salinas Valley during 2018 and 2019. The CropManage online decision-support system was used to guide evapotranspiration-based irrigation scheduling. Overhead sprinklers were used to establish the crop with 60-70 mm of water, followed by surface drip for the remaining crop cycle. A randomized complete block design, with six replications, was used to administer four treatments near 50%, 75%, 100% and 150% of estimated full crop water requirement (T50, T75, T100, T150) during the drip phase. An additional drip treatment at 125% (T125) was added in 2019. Applied water totals across treatments ranged from 199-410 mm in 2018 and 179-369 mm in 2019 (plus 35 mm of precipitation). No significant differences were observed between total curd (head) yields from T100 and T150 in year 1 (> 30 Mg ha-1), although marketable yield from T150 was greater. Total yield of T100 and T125 were significantly greater than T150 during year 2, but marketable yield was similar among T100-T150. No significant difference was observed in fresh or aboveground dry biomass production from T100 and T150. Significant reductions in yields and biomass production were observed in T50 and T75 for both years. T100 and T150 had the highest irrigation water productivity with respect to marketable yield. Nitrogen uptake and fertilizer N recovery were highest in T100 and T150 during 2018, but no significant treatment differences were observed in 2019. These field trials demonstrated that estimating crop evapotranspiration and irrigation requirements of cauliflower through a decision support service such as CropManage can be a reliable tool for irrigation scheduling.

Saltwater intrusion into coastal areas is a major problem that reduces acreage under vegetable production. Cultivating salt-tolerant varieties is one of the approaches to overcome this problem. The long-term goal of this project is to screen and identify salt-tolerant watermelon germplasm. We assessed the impact of salinity stress from natural brackish water collected in Charleston, South Carolina (32o47’38” N and 80o3’25” W), on the growth morphology of four watermelon cultivars to identify one discriminatory concentration to be used for evaluating hundreds of watermelon accessions available in USDA-ARS Germplasm Resources Information Network. Watermelon plants were hydroponically grown in a Nutrient Film Technique (NFT) system at various EC levels (natural brackish water diluted with de-ionized water to generate 5.5, 10, 12, 14, and 19 dS/m and control, 0 dS/m) and plant growth and shoot morphology were monitored. All cultivars failed to withstand salinity stress at 19 dS/m. Surprisingly watermelon cultivars tolerated fairly high levels of salinity (5.5-14 dS/m ⁓3,530 - 8,960 ppm salt concentration) with inhibited growth. Increasing EC levels correlated with decreased growth parameters such as plant height, leaf number, and shoot fresh and dry weight. Chlorophyll content and electrolyte leakage values increased with higher brackish water concentrations, peaking at 14 dS/m. These values were notably elevated, with chlorophyll content and electrolyte leakage being 5 and 2 times higher than the control, respectively. Cultivar Sugar Baby had significantly greater shoot length, chlorophyll content, and electrolyte leakage compared to other cultivars (Crimson Sweet, Charleston Grey, and Black Diamond). The other growth parameters were similar across all cultivars. Further research to identify an optimal EC between 14 and 19 dS/m for use in large-scale evaluation of germplasm accessions will be needed.

Increasing salinity levels pose significant challenges to coastal vegetable cultivation, particularly impacting salt-sensitive crops like cucumber, leading to reduced growth, development, yield, and quality. This study assessed the responses of six commercial cucumber cultivars to different salinity levels. Cucumber plants were grown in a hoop house hydroponically using various dilutions of brackish water in a Nutrient Film Technique (NFT) system at EC levels 3, 6, and 12 dS/m, along with adequate controls (0 dS/m). Increasing salinity levels caused a significant decline in plant growth parameters (shoot length, biomass, leaf number). Overall a 59% reduction in shoot length and 52% decrease in dry biomass was observed at 12 dS/m compared to control. The cultivar, Stripped Armenian had significantly greater shoot length (163 cm) and dry biomass (59 g), compared to the others (Diva, Katrina, Lemon, H-19 Little Leaf, and Suyolong) by 52-207% and 126-409%, respectively. Additionally, Stripped Armenians dry weight exceeded the control by 120%, 115%, and 25% in 3, 6, and 12 dS/m treatments, respectively. Gaseous exchange parameters measured with Licor 6850 (photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration) declined significantly with increasing salinity at vegetative and reproductive stages. The photosynthetic rate and stomatal conductance showed reductions of 15-17% and 13-50%, at salinity levels of 3 dS/m, 6 dS/m, and 12 dS/m, compared to the control treatment respectively. Similar reductions were also observed at the reproductive stage. Stripped Armenian consistently exhibited higher photosynthetic rate (4-27%), stomatal conductance (7-75%), and transpiration rate (6-56%) compared to other cultivars at vegetative and reproductive stages. In conclusion, Stripped Armenian demonstrated substantial tolerance to 12 dS/m salinity compared to other cultivars and may prove useful in saline environments, however further research is needed.

A rapid decline in water table of the Ogallala aquifer necessitates water conservation farming practices in Texas High Plains (THP). Deficit irrigation (DI) and biochar amendment strategies are widely adopted to sustain agriculture in semi-arid regions like THP. Although these practices are studied individually, research involving the combined effect of these factors is lacking, especially in THP. The goal of this study was to investigate the effect of DI and biochar application on soil water depletion, root distribution, and water use efficiency of cucumber in West Texas. A two-year field study was conducted in a split-plot design with irrigation levels as the main plots: I1[100% crop evapotranspiration (ETc) replacement before mid-season (EBM))-100% ETc replacement after mid-season (EAM), I2 (80% ETc EBM- 60% ETc EAM), I3 (60% ETc EBM - 80% ETc EAM), I4 (40% ETc EBM-40% ETc EAM)] and biochar rates [ 0 t/ha,15 t/ha, and 20 t/ha] as sub-plots with four replications. Results showed that I4 had the largest and I1 had the least soil water depletion, and the differences in water depletion among irrigation levels were significant up to 1-m soil depth. Root length density (RLD) and root surface area density (RSAD) were significantly higher in I1 followed by I2 and I3, and these parameters were the least in I4. Water Use Efficiency (WUE) showed I2 being the most water productive DI treatment with an average increase of 5% compared to I1. Biochar didn't influence water depletion, RLD, and WUE but significantly increased RSAD compared to non-amended plots. Thus, deficit irrigation level I2 can be a potential alternative irrigation to full irrigation for enhancing water productivity of cucumber in the THP. More pronounced biochar effects could be expected in long term studies.

This study aimed at conducting an impact evaluation of irrigation management practices in processing onion production. A three-year experiment was carried out in 15 commercial processing onion fields under different irrigation methods of furrow, solid-set sprinkler, and subsurface drip. The experimental sites were located in the Imperial Valley, California’s low desert region. All fields were on a 40-inch bed, six plant rows per bed with a spacing of 2.5-in between planting lines. The fields had a variable soil type with predominate soil texture from fine sandy to silty clay loam. Water, nitrogen, and energy used, bulb weights, soil moisture, soil nitrate and salinity, and actual evapotranspiration were measured in each site. A wide range of seasonal irrigation water applied was observed across the experimental sites. Irrigation water applied varied from 3.3 ac-ft/ac in a drip irrigated field to 6.9 ac-ft/ac in a furrow irrigated field. The results demonstrated that utilizing subsurface drip irrigation in processing onions could conserve 0.8 and 2.4 ac-ft/ac water in compared with solid-set sprinkler and furrow irrigation systems, respectively. The water productivity, the ratio of onion bulb weight to water applied, was determined 4.9, 4.3, and 2.7 t/ac-ft for the drip, sprinkler, and furrow irrigated fields, respectively. A greater nitrogen use efficiency was found in the drip irrigated fields compared to the sprinkler (15.2% points) and furrow (62.1% points) irrigated fields. The findings illustrated a higher salt accumulation on the topsoil (0-6 in. depth) in the drip irrigated fields. In other words, drip irrigation could cause salinity impacts in desert processing onions, and therefore, more frequent light irrigation events may be an effective tool to manage salinity. More nitrate leaching was also observed from the topsoil in the sites irrigated by sprinklers. Energy productivity, the ratio of onion bulb weight to fuel consumption, was 48.3% points higher in the drip fields than the sprinkler fields. The results revealed that irrigation practice has a significant impact on resource-use efficiency and environmental issues.

The escalating regulatory pressure to achieve sustainable groundwater use in California will demand improved irrigation efficiency. Even though approximately 80 to 90% of the sprinkler-applied water to a strawberry crop is lost through runoff, deep percolation and evaporation, all the strawberry fields in Ventura County are still irrigated with overhead sprinklers during crop establishment. This study quantified differences in water use, yield, canopy coverage and root depth between drip tape and micro-sprinkler irrigation during crop establishment at a commercial field located in Oxnard, CA during the 2023-2024 growing season. Treatments consisted of three irrigation methods used during the first five weeks: 1) primarily drip tape (DT), 2) micro-sprinklers only (MS), and 3) a combination of drip tape and micro-sprinklers (C). The irrigation scheduling of the MS treatment was defined by the irrigator (grower standard), while the DT and C treatments were guided by tensiometers and field observations. All other production practices remained the same. Each treatment was replicated four times in a randomized complete block design, with an area of approximately 1.7 acre per plot (40 beds of 350ft long). Treatments were carried out for 35 days from planting (Oct 5), after which drip irrigation became the only irrigation method. Total water use during establishment was very similar among treatments: 3.9, 3.6 and 4.0 acre-in for DT, C and MS, respectively. With four plant rows and three drip lines per bed, the DT treatment was irrigated for longer than anticipated to assure uniform soil moisture around the plant roots. Marketable yield until Mar 14 was 4,583, 4,229 and 4,297 lb/acre for DT, MS and C, respectively. Although not statistically significant, DT yield was 8.4% greater than MS (p-value = 0.802), and 6.7% greater than C (p-value = 0.865). Canopy cover trends were very similar between DT and C, while MS was between 13 and 29% lower than DT from 48 to 61 days after planting. Canopy coverage equalized at 90 days after planting after significant precipitation during Dec and Jan. Average root depth of DT was 38 and 19% greater than MS for 15 and 28 days after planting, respectively. In summary, this study found equal or superior crop performance of DT compared to MS during strawberry establishment. We expect that increasing the number of drip tape per bed from three to four would significantly decrease the irrigation time needed to provide ideal soil moisture, consequently decreasing water use.

This workshop will explore topics related to climate change impacts on temperate tree nut crops, including drought, salinity, freeze issues, and other environmental stressors. Additionally, participants will be given the opportunity to discuss relevance of topics to their specific commodity and share insights and suggestions with fellow researchers.

In this workshop we will be bringing in experts in pistachio and pecan cultivation to share their cutting-edge research and insights into mitigating the challenges posed by climate change. These esteemed speakers, who have dedicated their careers to understanding and addressing these issues, will provide valuable insight to workshop attendees and jumpstart discussion on this topic within groups. Attendees will have the opportunity to discuss relevant issues of climate change on their crop within small groups before bringing ideas to the entire group.

The impact of climate change on tree nut crops is likely to be significant, given expected decreases in chilling, increased droughts, and fluctuations in winter temperatures leading to decreases in production if mitigation measures are not implemented.

In this workshop, we seek to foster fruitful discussion among researchers working with tree nuts and other orchard crops likely to be impacted by climate change in order to brainstorm solutions and targets for future research in this topic area.

Coordinator(s)

• Lu Zhang, Oklahoma State University, Stillwater, OK, United States
• David Hlubik, Rutgers University, United States
• Phoebe Gordon, University of California Cooperative Extension, Madera, CA 93638, Madera County, United States

Speaker/Participant(s)

• Louise Ferguson, University of California Davis, Extension Specialist, Davis, California, United States
  Climate Impact on Tree Nut Crops - Pistachio Salinity (30 mins)
  Summary: Dr. Louise Ferguson is an Extension Specialist at University of California Davis with several decades of experience in pistachio and other orchard crops and will be speaking on pistachio salinity.
• Richard Heerema, New Mexico State University, Extension Specialist, Las Cruces, New Mexico, United States
  Climate Impact on Tree Nut Crops - Drought in Pecan (30 mins)
  Summary: Dr. Richard Heerema is an Extension Specialist at New Mexico State University with a focus on pecans and will be speaking on drought in pecan.
• Xinwang Wang, USDA ARS, College Station, TX, United States
  Climate Impact on Tree Nut Crops - Pecan Breeding Associated with Climate Change (30 mins)
  Summary: Dr. Xinwang Wang is a Research Geneticist for USDA ARS in College Station, TX and will be discussing challenges in pecan breeding associated with climate change.

Sponsored by National Issues Committee
Our work in horticulture is made possible to a great extent by Federal funding. That funding will only be available if Congress continues to value the work that we do with it. Therefore, all ASHS members should regularly let their representatives know how the funds are helping in your state or district. This session provides an understanding of how to confidently and effectively contact your Congressional district office about the value of programs that you know and use. This program is designed to be of particular value to members in the Western US, who are not likely to come to Washington DC for policy discussion.

This session will be a panel discussion to understand the perspective from the various offices involved and how they interact. The panel includes the actual people involved in this Congressional district.

• Kendra Oishi, District Chief, Office of U.S. Representative Jill Tokuda, Hawaii 2nd District.
• Anthony Ching, Director of Federal Relations for the University of Hawaiʻi System.
• Thomas Björkman, ASHS National Issues Committee and Cornell University
• Russell Galanti, Extension Educator, University of Hawaiʻi.