The Impact of Organic Crop Rotations and Ecological Weed Management Strategies on Soil Quality.

The use of cover crops within organically managed systems is a common practice to suppress weed populations and improve various soil biological, chemical, and physical properties. Our objectives were to evaluate the impacts of several cover crops on soil quality in an organic system in a 5 year study located in Ithaca, NE by measuring several soil quality parameters. The cover crop treatments used to suppress weed species and improve soil health in this study were sunn hemp (Crotalaria juncea), nitro radish (Raphanus sativus) and turnip (Brassica rapa), red clover (Trifolium pratense), a mixture of mustards species (Brassica spp.), all cover crop options, and no cover crops. The soil quality indicators measured were macroaggregate stability, bulk density, electrical conductivity, soil test potassium, soil test phosphorous, total organic carbon and soil microbial biomass. How the 3 year organic corn-soybean-wheat crop rotation, and cover crops within that organic rotation, influenced soil quality, was assessed using the Soil Management Assessment Framework (SMAF). How these same treatments influenced soil microbial communities was assessed by integrating below ground and above ground measurements using a random forest classification and regression model. Understanding how cover crops and organically managed systems impact soil quality may serve to encourage producers in adopting organic practices.