SINful Consequences of Cover Cropping: Soil Inorganic Nitrogen (SIN) Provision and Retention from Warm-Season Cover Crops for Northern US Region Vegetable Production

Abstract

Warm-season cover crops are promising tools to meet vegetable crop nitrogen (N) demands while preventing N losses but more information is needed to achieve these goals in the northern US region. We explored warm-season cover crops in two rotations in Minnesota to evaluate biomass production, N provision and retention benefits, and impacts on vegetable yields. Warm-season cover crop biomass production ranged from 628-13,350 kg ha-1 and did not frequently exceed a weedy control. Soil nitrate decreased beneath cover crops and increased post-termination, demonstrating seasonal patterns potentially synchronous with vegetable demand. Cover crops reduced nitrate leaching to buried resin lysimeters by up to 50% but not significantly. Vegetable yields were often decreased following cover crop treatments, though legumes boosted vegetable yield in limited site-years. Evidence from this study suggests that warm-season cover crops could synchronize seasonal N patterns with vegetable demand but may not boost vegetable yields.