Polyethylene mulch films have become a dominant production practice to increase the yield potential of high value crops, but they are a significant source of environmental contamination. Alternatively, biodegradable mulches are a potentially sustainable alternative , but are less popular among growers as they vary in durability and performance in the field environment. Cover crops when sufficiently tall may be able to improve biodegradable mulch durability by reducing wind intensity within a mulched bed. To quantify the utility of a cover crop windbreak, we tested the effect of a fall-planted, 6ft wide strip of cereal rye planted parallel to the southern side of mulched bell pepper beds. Whole plot treatments included presence or absence of rye and split plot treatments included a comparison of polyethylene mulch, biodegradable mulch, and a bare ground control. Day windspeeds were reduced in peppers protected by a south-facing cereal rye strip by 60% relative to unprotected peppers. Large hole occurrences in biodegradable mulch were reduced by 50% and small holes by 15% in peppers protected by a cereal rye strip relative to unprotected peppers. Peppers grown behind the cover of cereal rye had a 42% reduction in leaning plants compared to peppers without cereal rye. Stomatal conductance was increased by 27% in peppers protected by cereal rye relative to unprotected peppers as a result of reduced windspeeds, though there were no differences in fruit yields. Results suggest cover crops can extend the useful life of biodegradable mulch films, which may help address a common barrier to adoption. Ongoing research aims to better understand the effects of the cover crop on crop health, yield, and quality.
High tunnel production of day-neutral strawberries is a promising production system in the central U.S. The use of different colored plastic mulches in a high tunnel production system can vary the microclimate around plants and alter yield and fruit quality. This study was conducted to identify the most appropriate color plastic mulch in a high tunnel production system as it relates to yield and fruit quality. The experiment was conducted at the Kansas State University, Olathe Horticulture Research and Extension Center in 2020 and 2021 using a split-plot, randomized complete block design. We evaluated six plastic mulches (black, white, striped silver, silver, red, and green) and two day-neutral cultivars, ‘Albion’ and ‘Portola’. Soil temperature and UV light reflected from the mulch were measured to monitor microclimate modifications. Fruit quality was assessed by overall visual quality, color, soluble solids content, titratable acidity, sugar/acid ratio, total phenolics, and anthocyanin content of strawberries. 'Portola’ produced greater yields than ‘Albion’, but ‘Albion’ had better fruit quality. The plastic mulches altered the reflected UV light and soil temperatures. During the mid and late season, the silver mulch had higher fruit yields than the red and green mulches, likely due to its ability to limit solar warming during warm production months. The mulches had inconsistent impacts on fruit quality. Overall, the silver mulch maintained the best microclimate for day-neutral strawberry production in high tunnels.
Amrita Mukherjee, Urban Agriculture/Small Farm Advisor at the University of California Agriculture and Natural Resources in Southern California, focuses on research and education in organic farming, urban agriculture, and sustainable practices for small-scale growers in both field... Read More →
Agricultural plastic mulch made from non-biodegradable polyethylene (i.e., “PE mulch”) provides many horticultural benefits. However, PE mulch requires annual removal and disposal, which generates large volumes of plastic waste that is rarely recycled and can become a pollutant. Incomplete removal of PE mulch also can leave behind plastic fragments that threaten soil and ecosystem health. To address these challenges, soil-biodegradable mulches (BDMs) have emerged as a potentially more eco-friendly alternative. BDMs are designed to provide the same advantages for specialty crop production as PE mulch and naturally biodegrade when incorporated into the soil. In addition, non-biodegradable reflective mulch has emerged as a promising mulch technology that may reduce key insect pests. The objective of this research was to evaluate the impacts of different mulch technologies, including soil-biodegradable and reflective mulches, on horticultural and pest dynamics in day-neutral strawberry (Fragaria×ananassa cv. Albion) in northwest Washington. Seven mulch treatments were established in a randomized complete block design with four replications in 2023. Treatments included green and black BDM made with ecovio and Mater-Bi feedstocks, non-biodegradable metalized mulch, and controls of black PE mulch and unmulched plots. Yield from all mulch treatments did not differ significantly from black PE control except for the green BDM made with ecovio feedstock. The green BDM made with ecovio resulted in significantly lower (32%) yield, similar to unmulched control. Lower yield may be attributed to the rapid deterioration of the green BDM treatments, which lacks carbon black and deteriorated more rapidly compared to other mulch treatments. However, black BDM made from MaterBi feedstock and metalized mulch were 37% and 11% less deteriorated than PE control respectively. Additionally, all mulch treatments suppressed weeds better than the unmulched control and were not different from black PE mulch. Aphid and thrips populations were highest in unmulched plots, whereas metalized mulch had fewer thrips (on sticky cards) and fewer aphids (on leaves) than all other treatments. Overall, the study highlighted that black BDM performs similarly to PE mulch with regards to potential weed suppression and maintenance of yield, whereas the rapid deterioration of green BDM could effect the soil microclimate and subsequent plant growth. Despite rapid mulch deterioration, the study did not observe compromised weed management. Metalized mulch may contribute to reducing pest populations but impacts on pollination and biological control remains unknown. Additional research on soil health effects is required given the fate of BDMs is in-soil incorporation.
Habanero chili fruit is shiny, orange, or red, about 5 cm long, and very pungent (200,000 to 300,000 Scoville heat units). It is popular in Mexico, Central America, and the Caribbean, although it is increasing in demand in the U.S. There is reduced information on chili production under shade nets. The objective was to determine the effects of shade level and cultivar on the fruit yield of habanero chili. The study was conducted in Tifton, Georgia, under field conditions in two seasons. Habanero plants were grown using raised beds, black plastic film mulch, and drip irrigation, following the University of Georgia extension recommendations for bell peppers. The experimental design was a randomized complete block with four replications and 10 treatments (5 shade levels x 2 cultivar combinations). Habanero chili ‘Kabal’ and ‘Kukulkan’ were grown at 0% (unshaded), 30%, 47%, 62%, and 80% shade levels. Marketable fruit number and yield decreased quadratically with shade level, although there were no statistical differences in marketable yield for plants in unshaded conditions and 30% and 47% shade levels. Mean marketable yields were 33.6 t/ha (unshaded) and 5.7 t/ha (80% shade level). Less than 2.5% of total fruit were affected by sunscald and blossom-end rot. Total and marketable fruit numbers and yields and individual fruit size were higher in ‘Kukulkan’ than in ‘Kabal.’ In conclusion, although shading increased fruit size, it did not improve marketable yield compared to unshaded conditions.
Compared to standard polyethylene agricultural covers, plants grown under quantum dot-infused covers (QD, QDCs) that redshift the light spectrum have exhibited greater yields. While whole-plant and -canopy morphological changes under photoconversion products have been documented, impacts on seedling growth rate (<3 weeks post-germination) are not known. In the current study, four microgreens (alfalfa [Medicago sativa], amaranth [Amaranthus tricolor], kohlrabi [Brassica oleracea var. gongylodes], and pea [Pisum sativum]) were grown in an ebb and flow hydroponic growth chamber under metal halide lamps coupled with QDCs (UV/blue to red/far-red) containing different QD concentrations. Growth measurements derived from image-based phenotyping and traditional, destructive methods were analyzed on a species-specific level. Plants exhibited increased leaf area, biomass accumulation, and growth rate on a species-specific basis. Commercially relevant, it was estimated that some species could be ready for sale days earlier than their control counterparts. Germination rate was not affected significantly.
