Biological and biochemical soil properties in no-till corn with different cover crops

ABSTRACT:

Cover cropping impacts soil properties in many positive ways. These include higher total carbon, which usually contributes to increased cation exchange capacity and water-holding capacity. Enhanced soil physical and chemical properties, result in a better environment for the activity of soil microorganisms. We conducted a study of biological properties in no-till corn plots receiving either 0 or 168 kg N ha⁻¹. Plots were planted in the fall each year with a hairy vetch (Vicia villosa Roth), winter wheat (Triticum aestivum L.), or no cover crop. The vetch cover resulted in the highest organic C accumulations, and the addition of N to the wheat or no cover plots increased C relative to the no N treatments. Soil organic C was not different between the vetch with and without N, but pH was significantly reduced by N fertilization. Hairy vetch had a greater effect on microbial numbers than did the wheat cover or no cover. The greatest bacterial numbers were observed in the vetch with no N treatment. Acidphosphatase, arylsulfatase, β-glucosidase and L-asparaginase activities were all higher in the vetch with no N treatment than any of the other combinations. In the wheat and no cover treatments, the enzyme activities mentioned earlier were all higher in the 168 kg N treatments. Soil treatments that increased soil organic C enhanced the activity of soil microorganisms and/or provided a better environment for the stabilization of microbially produced soil enzymes. Our data indicated that the use of cover crops significantly enhanced soil biological properties as measured by microbial numbers and enzyme activities. The use of cover crops provides soil quality benefits in addition to the reduction in soil loss attained with these systems.