Evaluation of Soil Quality in Vegetables Planted in Plastic Mulch Vs. No-till in Polyculture Cover Crop.

Organic vegetable production relies heavily on tillage and the use of polyethylene film as a form of weed control. Studies have shown that both continual tillage and the use of polyethylene film contribute to the degradation of soil quality and can lead to increased erosion, loss of organic matter and microbial populations, and a decline in nutrient availability. Paired with no-till strategies, growing cover crops can help improve soil organic matter content, increase microbial populations, reduce soil erosion, and reduce the need for mineral amendments. These improvements to soil quality can subsequently lead to increased productivity and yields. Still, even with the soil quality benefits, no-till practices are challenging to implement on organic vegetable farms because of the issue of weed control. In this study seven organic growing systems in central Missouri were evaluated that utilize either a polyculture cover crop, no-till, or tillage and polyethylene, straw, or fabric mulch to determine which systems provide best practices for weed control, soil quality, crop yield and profitability. This system utilizes no-till with rolled or mowed cover crops or tillage with polyethylene film, landscape fabric, or straw mulch and crops are transplanted. During the past two years we have found that tomato trials shows the most potential for successful harvest of the crop from a no-till rolled plot, most likely due to the increased success of terminating the winter cover crop mix during the proper stage, though the reemergence of hairy vetch continues to be a problem. We also found that for the early season lettuces, the cover crop is rolled/crimped too early and it continues to grow, causing competition and reducing yields. Active carbon is highest following rolled cover crops compared to tillage. Other soil health parameters: soil fertility, aggregate stability, soil nitrogen, PFLA, and leaf analysis will be presented.