Management impacts on GHG emissions and yield for an organic soybean crop
As demand for organically grown food increases, growing organic soybean can be profitable and also improve soil ecosystem services through sustainable agronomic practices. However, because most chemical inputs are restricted from organic agriculture, producers rely heavily on tillage for weed control, which in turn can be detrimental to soil health. The use of cover crops, which can be employed to suppress weed growth, may provide an alternative to tillage for sustaining yields. Compost can be used as a fertilizer for organic soybean, however the ideal rate is not always known. Agricultural land has been recognized as a significant source of greenhouse gas (GHG) emissions, however GHG release from soils may vary according to crop production strategies utilizing cover crops and compost. The purpose of this investigation was to determine the effects of tillage, cover crop, and compost rate on yield and the soil release of two GHG, N2O and CO2, under an organic soybean cropping system grown on a Missouri claypan soil. A corn (Zea mays)-soybean (Glycine max)-wheat (Triticum aestivum) organic cropping system was initiated in 2012 at the University of Missouri Bradford Research Center near Columbia, MO using a randomized complete block, split-plot design with four replications. Each crop was investigated independently with tillage/cover crop combinations as the main plot treatment and compost rate for the split-plot treatment. Tillage/cover crop treatments included tilled without cover crop (Till), tilled with cover crop (TillCC), and no-till with cover crop (NTCC). Compost rates were based on soil-test phosphorous recommendations from the University of Missouri Soil Testing Laboratory. Compost treatments were 0, half the recommended rate (0.5RR), the recommended rate (RR), and 1.5 times the recommended rate (1.5RR). Gas samples were collected at least once a week during the 2012 and 2013 growing seasons, and several times in succession after significant events such as rain, irrigation, and cultivation. Neither tillag
Author supplied: greenhouse gas, soybeans, organic, cover crop, tillage, compost
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