Cover Crops Impact On Soil Quality and Crop Yield.

Cover crop is an important component of sustainable agriculture. The long-term effects (2004 to 2009) of cereal rye and Cowpea as cover crops in conventional till corn-soybean (CT-CS), CT corn-soybean-wheat (CT-CSW), no-till corn (NT-C) and NT corn-soybean-wheat (NT-CSW) rotations on soil quality were evaluated. Soil composite samples were collected at 0-15 and 15-30 cm depths from GPS guided locations, processed, and analyzed for selected biological (toatl microbial biomass, biological activity, metabolic quotients, and enzymes), chemical (pH, electrical conductivity, total, active, and particulate carbon and nitrogen, cation exchange capacity), and physical (bulk density, porosity, aggregate size distribution, aggregate stability, MWD and GMD, aggregate ratio, etc.) quality parameters. Crop yields were recoded. Soil quality indices were calculated using inductive and deductive data. Results showed that microbial biomass increased under NT (15-40%) and decreased (37%) under CT over time. Rye and Cowpea used as cover crops in NT postively impacted (25%) the microbial biomass content. Biological activity positively impacted by 12% and the enzyme activity by 6%. Total C content decreased by 5% in CT-CS and increased by 28% in NT-CSW. Total N increased by 6% in CT-CSW and 23% in NT-CSW. Active C and particulate organic matter increased by 18 and 17% in CSW with cover crops under NT over time. Soil aggregate stability, as a measure of physical quality, increased sighnificantly over time. Crop yield increased by 12% under NT CSW with cover crops than CT-CSW.