Effects of Organic No-till and Winter Cover Crops on Soil Health and Yield on a Claypan Soil.

Organic row-crop agriculture traditionally uses multiple tillage for weed control. Because tillage can lead to increased breakdown and loss of soil organic matter, destruction of soil structure and decreased water infiltration and holding capacity, practices that reduce tillage are being sought for organic weed control. In organic no-till, a cover crop is grown to reproductive stage and killed using a roller/crimper. The residue from the crimped cover crops stays attached to the soil and stays in the field as a weed-blocking mat. To examine the effects of organic no-till vs. organic till on soil health, three systems were compared: no-till with a crimped cover crop, tilled with a cover crop and tilled with no cover crop. Crops utilized were corn (Zea mays), soybean (Glycine max) and wheat (Triticum aestivum), and the winter cover crops were cereal rye (Secale cereale) and hairy vetch (Vicia villosa). Four rates of turkey litter compost for crop fertility were utilized in a split plot design. Measurements taken include cover crop biomass, crop yield, soil aggregate stability, active carbon, TOC, TON, soil inorganic N, microbial PLFA, and β-glucosidase activity. Soybean yields in organic no-till were competitive except in year 3 of the experiment when soybean yields were greatly reduced due to poor cover crops stands and reduced weed control from the crimped cover crops. Yields in corn and wheat were more affected by compost rate than tillage and cover crop, although corn was adversely affected by poor stands in the crimped cover crop. Active carbon levels were somewhat influenced by compost rates while total organic carbon was lower in the tilled treatment with no cover crop. Β-glucosidase activity and AMF biomass were higher in plots utilizing no-till. Active carbon, TOC and AMF were all highest in plots with winter wheat followed by a summer cover crop.