Andrea D. Basche, Thomas C. Kaspar, Sotirios V. Archontoulis, Dan B. Jaynes,Thomas J. Sauer, Timothy B. Parkin, Fernando E. Miguez
In the Midwestern United States crop growth and yield are often reduced by short periods of drought during the growing season. One approach for farmers to adapt to this variability is to utilize crop and soil management practices that enhance soil water storage, which would reduce the risks drought-induced crop water stress. Some research has indicated that a winter rye cover crop grown between harvest and planting in corn and soybean rotations can increase soil water availability, but producers continue to be concerned that water use by cover crops will reduce water available for a following cash crop. In this study we made measurements of soil water storage capacity and soil water content throughout the growing season and corn and soybean growth and yield from 2008 to 2014 at a Central Iowa research site that has included a winter rye cover crop in a corn-soybean rotation for thirteen years. We found that the cover crop increased the soil water storage capacity by 21-22% in the upper 12 inches of soil and that the cover crop water use did not reduce the water available for corn and soybean growth. Although cover crops use water when they are alive and growing, after they have been terminated with herbicides in Iowa new rainfall normally replenishes soil water content. This most likely occurs because the cover crop improves water infiltration and storage and the residues mulch the surface reducing evaporation. Corn and soybean growth and yield were not affected by the presence of the cover crop before planting. This research indicates that the long-term use of a winter rye cover crop can improve soil water dynamics and storage without sacrificing water availability or crop yield in corn-soybean crop rotations in the Midwestern United States. This should reduce producer concerns about cover crop water use in Iowa and should increase producer adoption of cover crops.
Article Citation: A.D. Basche, T.C. Kaspar, S. Archontoulis, D.B. Jaynes, T.J. Sauer, T.B. Parkin, F.E. Miguez. Soil water improvements with the long-term use of a winter rye cover crop. Agric. Water Manag., 172 (2016), pp. 40–50 http://dx.doi.org/10.1016/j.agwat.2016.04.006
Science Direct article here.