Improving Soil Conservation and Crop Performance through Reduced Tillage and Cover-Crop-Based Rotations in Organic Squash Production

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2017-04-11
Authors
Johnson, Rebecca
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Horticulture
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Horticulture
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In recent years, there has been a surge in organic vegetable production in Iowa, increasing to 1,264 acres, and bringing in $2.5 million in annual sales. Reduced tillage in vegetable operations provides multiple environmental benefits for soil conservation, as well as reducing machinery, labor and fuel costs. On organic farms, an innovative roller/crimper is used in lieu of herbicides to terminate cover crops. The objective of this research included an investigation of the feasibility of adopting conservation tillage practices for organic squash production. Cover crops of hairy vetch and rye were planted on October 18, 2015, at the ISU Neely-Kinyon Farm, Greenfield, Iowa, and terminated the following spring with a roller/crimper. Organic squash transplants (‘Delicata,’ Johnny’s Seed, Albion, ME) were planted on June 14, 2016. Cover crop biomass averaged 5,323 lb/acre across all plots. Treatments consisted of organic no-till and tilled cover crops, along with compost and mulch comparisons. Over two harvest periods, squash from tilled, compost and mulch treatments had the greatest numerical yields, averaging 18,023 lb/acre, while no-till plots averaged 4,590 lb/acre. Yields from notill plots receiving compost, however, were not statistically different from tilled compost plots. Mulch provided additional yield benefits when compared to no mulch treatments. Previous soil quality results showed higher soil quality in no-till plots, including more soil nitrate-N and greater macroaggregation compared to tilled plots. Cover crops also added higher amounts of soil organic carbon. The on-going challenge is to synchronize organic no-till vegetable crop growth with nitrogen release from cover crops

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