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The application of seaweed extract and microbial biostimulants has been suggested as a promising approach to overcome yield-limiting factors in organic farming. Yet, information regarding their impact on organic strawberry production is limited. This 2-year field study evaluated the effect of seaweed extract and microbial biostimulants and their synergistic effects on strawberry plant growth, nutrient uptake, fruit yield, and quality under organic production. The biostimulant effects were compared on two strawberry cultivars: Sweet SensationVR Florida127 and Florida Brilliance. Over two seasons, the combination of seaweed extract plus microbial biostimulants applied biweekly consistently resulted in a significant increase of whole-season marketable and total strawberry fruit yields by 23% and 20% on average, respectively, compared with the no-biostimulant control. Application of either biostimulant alone did not consistently show positive effects on strawberry productivity. Modified strawberry root system architecture, enhanced N uptake, increased number of crowns, and higher soil respiration were observed in the biostimulant combination treatment in contrast to the no-biostimulant control. The biostimulant impact was not influenced by strawberry cultivar, but genotypic difference in yield performance under organic production was observed. 'Florida Brilliance' produced significantly higher total fruit number and yield than 'Florida127' by 26% and 12%, respectively, in the first season, and by 34% and 11%, respectively, in the second season. Marketable fruit number (by 18%) and yield (by 9%) of 'Florida Brilliance' were also higher in the first season, along with greater marketable fruit number (by 31%) in the second season. In addition, 'Florida Brilliance' showed significantly higher values of SPAD index, photosynthetic rate (early harvest), and fruit mineral contents based on dry weight (late harvest) than 'Florida127' in both seasons. Although the biostimulant treatments exhibited little influence on the fruit quality attributes including soluble solids content (SSC), titratable acidity (TA), SSC/TA, and total anthocyanin content, varietal differences were observed with significantly higher levels of SSC and lower contents of total anthocyanins in 'Florida 127' vs. 'Florida Brilliance' during each season. The benefits of combined application of seaweed extract and microbial biostimulants demonstrated in this study suggest the need to further elucidate their synergistic functions in promoting nutrient uptake and fruit yield in organic strawberry production systems under different soil and environmental conditions. [ABSTRACT FROM AUTHOR]

Despite the growing interest in high tunnel organic vegetable production, limited information is available regarding optimizing nutrient management for organic leafy greens. This 3-year study examined the impacts of cowpea cover crop as well as different organic fertilizers and composts on yield, leaf mineral nutrient content, and phytochemical properties of organic leafy greens produced in high tunnels under Florida sandy soil conditions. The experiment was arranged in a split-split-plot design with three replications. The whole plots consisted of a cowpea (Vigna unguiculata 'Iron & Clay') cover crop and a weedy fallow control, with fertilization treatments in the subplots, including preplant application of granular fertilizer vs. weekly injection of liquid fish fertilizer at the same seasonal rates of nitrogen (112 kg/ha), phosphorus (9.8 kg/ha), and potassium (74.4 kg/ha). The sub-subplots included yard waste-based compost (22.4 Mt/ha), cow manure-based compost (22.4 Mt/ha), vermicompost (5.6 Mt/ha), and no compost control. Cowpea was broadcasted (112 kg/ha) in early July or mid-August and terminated 51 to 53 days after seeding. Pac choi (Brassica rapa var. chinensis 'Mei Qing Choi') was transplanted inmid-Sep. ormid-Oct. and harvested after 33 to 36 days. Baby spinach (Spinacia oleracea 'Corvair') or baby leaf lettuce (Lactuca sativa 'Outredgeous') was direct seeded subsequently as a catch crop. Each experimental unit remained in the same location across the 3 years of the study. Cover cropping had little influence on yields, leafmineral nutrients, ascorbic acid content, total phenolics, and total antioxidant capacity of pac choi and baby spinach/lettuce. Compared with preplant application of the granular organic fertilizer, weekly liquid organic fertigation improved pac choimarketable yield and dryweight by 16.8%and 5.4%on average, respectively, and enhanced leaf nitrogen and phosphorus contents on a dry weight basis. Relative to the no compost control, yard waste compost consistently improved marketable yields of pac choi by 11.6%on average and led to higher yields of the baby spinach/lettuce catch crop in years 1 and 3, suggesting that compost applications may enhance seasonal nutrient availability to better meet crop demand. However, compost application exhibited inconsistent effects on crop mineral nutrient and phytochemical contents across the years, which could be attributed to the different nutrient compositions of the composts applied in each season, as well as the legacy effects from the previous season. Furthermore, the compost benefits may be influenced by the fertilization programas indicated by their interaction effects observed in this study. [ABSTRACT FROM AUTHOR]

Bruising of strawberry (Fragaria 3ananassa Duch.) fruit is a common mechanical injury that reduces product value. Wound-induced ethylene may accelerate deterioration or decay, affecting strawberry quality and shelf life. However, bruising susceptibility varies among strawberry cultivars. In this study, cultivars Monterey, Sweet Sensation, Radiance, and two proprietary cultivars (Cultivar A and Cultivar B) from a private breeding program were investigated to evaluate their bruising susceptibility and wound response. Bruising consisted of dropping a 28-g steel ball from 27 cm onto individual fruit; unbruised fruit were the primary control, while fruit exposed to 1 mL·LL1 ethylene were used as a check for ethylene response. All fruit were stored at 20 8C, 90% relative humidity (RH), with respiration and ethylene production measured at 2-hour intervals for 24 hours. Appearance observations were recorded daily until decay onset. Peak respiration rates of 30-40 mL CO2·kgL1·hL1 mostly occurred within 4 hours ('Cultivar B') to 6 hours ('Cultivar A' and 'Sweet Sensation') after bruising, except 'Monterey', which peaked at 60 mL CO2·kgL1·hL1 in 2 hours, and 'Radiance', which reached 70 mL CO2·kgL1·hL1 in 6 hours. Maximum ethylene production rates after bruising were 0.05 to 0.06 mL·kgL1·hL1 for 'Monterey', 'Cultivar A', and 'Cultivar B', 0.10 mL·kgL1·hL1 for 'Sweet Sensation', and 0.20 to 0.37 mL·kgL1·hL1 for 'Radiance'. 'Cultivar B', with the lowest ethylene production, exhibited the lowest overall bruising severity, whereas 'Radiance', with the highest ethylene production, exhibited the most severe bruising-induced water soaking, and the other cultivars were intermediate, although 'Monterey' bruises were more discolored than those of the other cultivars. 'Monterey', 'Radiance', and 'Sweet Sensation' showed more yellowing and browning of the calyx in response to both bruising and ethylene exposure than 'Cultivar A' and 'Cultivar B'. Except for 'Cultivar B', bruising and ethylene exposure increased decay severity. [ABSTRACT FROM AUTHOR]