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Paulsen, 1968 ). Cantliffe (1972b) found that the TNC of spinach grown for 12 h in light of ≈500 μmol·m −2 ·s −1 was 22% lower than spinach exposed to 6 h of light at the same intensity. To lower TNC in leafy greens grown for human consumption

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Leafy greens are a rich dietary source of nutrients including calcium, magnesium, potassium, and iron ( Kopsell et al., 2004 ). In addition, many leafy greens, particularly those of the Brassicaceae family, contain high levels of plant secondary

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cultivation in Washington State and may expand the market for leafy greens in the region and other areas with similar climatic conditions. The purpose of this study was to assess the yield of leafy green vegetables grown for a salad mix in a high tunnel during

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Nutrient availability may depend on method of fertilization particularly when the root medium is cool. The salad greens, arugula, lettuce, and spinach, were grown in spring, fall, and winter using organic or conventional fertilization to test this hypothesis. Field plots were mineral soil fertilized with 10N-10P-10K, or soil was amended with leaf compost and cotton-seed meal. Unheated high-tunnel plantings plots contained either perlite fertilized with a complete soluble fertilizer or a 1 leaf compost: 1 perlite mixture fertilized with cotton-seed meal. There was no consistent difference in growth due to the method of fertilization, either in the field or in high tunnels. Over all plantings in field and high-tunnel plots, concentrations of nitrogen and phosphorus were higher in leaves of plants grown with leaf compost. The time of year did not affect the difference in composition between plants grown in compost and perlite in a manner that could be related to the environment or rate of growth. Although relative growth rates were only 5% per day in high tunnels in winter compared to 10% to 18% per day in other seasons, the difference in reduced nitrogen among plants grown in compost and perlite was similar in winter and summer. The changes in composition due to method of fertilization were similar in all three plant species under study.

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Leaf tissue composition may depend on season and method of fertilization. Lettuce and spinach were grown in spring, fall, and winter in unheated high tunnels using organic or conventional fertilization. The root medium was either perlite fertilized with a nitrate-based complete soluble fertilizer, or leaf compost/perlite 1:1 v/v fertilized with cottonseed meal. Growth rate did not differ due to the method of fertilization, but specific leaf area was 10% greater with compost. Growth in compost raised the concentrations of total reduced nitrogen, phosphate, and potassium in both species. Effects of season were factored with a 3rd-order polynomial in Julian day. Nitrate, total phosphorus and potassium varied with season. Interaction of effects of season and fertilization were only significant for total reduced nitrogen and phosphate in leaves of lettuce. The difference in nitrogen due to fertilization was larger in fall harvests than at other times of year. There was a similar, but nonsignificant, trend with time for total reduced nitrogen in spinach. Differences in nitrate due to fertilization were small, compared to those of reduced nitrogen. The same seasonal trend in potassium was seen in both species, and for both methods of fertilization. Concentrations were highest in spring and lowest in fall.

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Steam injected into the soil, raising soil temperatures to >70 °C for 15 to 20 minutes, will control weed seed and soilborne pathogens. The effect of this reduction in the weed seedbank viability results in weed control in the treated zone that can persist for several weeks or months. The effect of steam pasteurization of soil on weed seeds produces results similar to a preemergence herbicide. In our study, steam was applied to the soil to control weed seed and propagules of Sclerotinia minor and Pythium spp. Replicated field trials in carrot, lettuce, and spinach were conducted using two types of band steam applicators in 2020 and 2021. Data collected were soil temperatures after steam application, weed control, hand weeding times, diseased plant counts, pathogen populations in the soil, and crop yields. Post-steam soil temperature intervals >70 °C in the top 10 cm of the soil ranged from 67 to 176 minutes. Steam reduced weed densities by 64% to 100% and lowered hand weeding times by 23% to 91%. The reduction of S. minor sclerotia propagules after steaming was 69% to 95% compared with the no steam control. The percentage of lettuce plants infected with lettuce drop was reduced by 60% to 70% and the reduction of Pythium spp. propagules in the soil was reduced by 50% to 100% compared with the no steam control, respectively. Lettuce head diameters in steamed soils were 10% to 24% larger compared with the no steam control. Carrots grown in the steam-treated soil had a 10% greater root diameter than the no steam control. Steam increased lettuce yields in two of three trials 22% to 28% compared with the no steam control. Gross revenues for the steam-treated lettuce were $3231/ha higher than in the no steam control. The data suggest that band steam is a viable soil pest control treatment for vegetable crops.

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“ Brassica leafy greens” is a general term that includes several important vegetable crops, such as turnip greens ( Brassica rapa L.), mustard greens ( Brassica juncea L.), collards and kale ( Brassica oleracea L. Acephala Group). More than 28

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was determined for specific Asian vegetables, leafy greens, and herbs which were identified as to species, named in Asian languages, and chosen for their horticultural feasibility in east coast markets. This selection process of leading crop candidates

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-like leafy greens (germplasm information available from Dryad data repository, doi:10.5061/dryad.4851qq0). The Brassica leafy green commercial cultivars (obtained from Abbott and Cobb Seed Co., Feasterville, PA), ‘Topper’ ( B. rapa turnip green) and ‘Top

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). Nitrate-N concentration in leafy greens can fluctuate diurnally because it is often inversely related to light intensity ( Muramoto, 1999 ; Reinink, 1991 ; Steingrover et al., 1986 ; Steingrover and Ratering, 1986 ). As a result of rapid NO 3 -N

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