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  • Author or Editor: C. A. Sanchez x
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About 33% of all irrigated lands worldwide are affected by varying degrees of salinity and sodicity. Soil with an electrical conductivity (EC) of the saturated extract >4 dS·m−1 is considered saline, but some horticultural crops are negatively affected if salt concentrations in the rooting zone exceed 2 dS·m−1. Salinity effects on plant growth are generally osmotic in nature, but specific toxicities and nutritional balances are known to occur. In addition to the direct toxic effects of Na salts, Na can negatively impact soil structure. Soil with exchangeable sodium percentages (ESPs) or saturated extract sodium absorption ratios (SARs) > 15 are considered sodic. Sodic soils tend to deflocculate, become impermeable to water and air, and puddle. Many horticultural crops are sensitive to the deterioration of soil physical properties associated with Na in soil and irrigation water. This review summarizes important considerations in managing saline and sodic soils for producing horticultural crops. Economically viable management practices may simply involve a minor, inexpensive modification of cultural practices under conditions of low to moderate salinity or a more costly reclamation under conditions of high Na.

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The goal of this study was to develop a systems-based strategy for organic muskmelon (Cucumis melo var. reticulatus) in Pennsylvania (PA), Iowa (IA), and Kentucky (KY) to manage bacterial wilt (Erwinia tracheiphila) and nutrients while safeguarding yield and enhancing early harvest. Spunbond polypropylene rowcovers deployed for different timings during the growing season were evaluated for suppressing bacterial wilt and locally available compost was applied based on two different estimated rates of mineralization of organic nitrogen (N) to manage nutrients. In KY only, the use of rowcovers suppressed bacterial wilt incidence compared with not using rowcovers. However, the timing of rowcover removal did not impact wilt incidence. Under lower cucumber beetle [striped cucumber beetle (Acalymma vittatum) and spotted cucumber beetle (Diabrotica undecimpunctata howardi)] pressure in PA and IA, rowcovers did not consistently suppress season-long incidence of bacterial wilt. In four of five site-years in PA and IA, more marketable fruit were produced when rowcovers were removed 10 days after an action threshold (the date the first flower opened in PA; the date when ≥50% of plants in a subplot had developed perfect flowers in IA and KY) than when no 10-day delay was made or when no rowcovers were used. In addition, the no-rowcover treatment consistently had lower weight per marketable fruit. In KY, the same action threshold without the 10-day delay, followed by insecticide applications, resulted in the largest number of marketable fruit, but did not affect marketable fruit weight. In PA, marketable yield was higher using compost compared with the organic fertilizer in 1 year. No yield differences were observed by nutrient treatments in 2 years. In IA, marketable yield was lower with the low amount of compost compared with the organic fertilizer and yields with the high amount of compost were not different from the low amount or the organic fertilizer in the year it was evaluated. In KY, marketable yield was unaffected by the nutrient treatments in the year it was evaluated. Given these results, muskmelon growers in PA, IA, and KY who use compost may choose the lower compost rate to minimize production costs. Overall, these findings suggest that rowcover-based strategies for organic management of bacterial wilt need to be optimized on a regional basis, and that fertilization with compost is compatible with these strategies.

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