Simulated Effects Of a Cover Crop On The Yield Of a Following Crop Using Process-Based Modeling.

The addition of cover crops into non-irrigated crop rotations is a potential method to reduce erosion, improve long term soil quality and realize other conservation benefits.  The conservation benefits of cover crops in non-irrigated systems can only be realized and widely adopted when the effect of cover crops and timing of termination on the yield of following crops is understood and predictable. A study was designed using the Wind Erosion Prediction System WEPS to simulate crop growth and yields for a Spring Wheat – Triticale Cover Crop – Field Corn rotation with termination timings of 35, 20 and 5 days prior to planting the following crop corn.  The growth and yield for the 3 cover crop management treatments and 1 check management treatment of Spring Wheat – Field corn without a cover crop was evaluated for 10 locations, 7 soils and 2 residue/tillage management systems.  Crop yields and soil profile hydrology information was gathered from each simulation and the results for the cover crop treatments were evaluated as a fraction of the corresponding results for the check treatments.  The relationships between yield of the corn crop following a cover crop and cover crop timing, biomass yield, climate, soils and residue tillage management were studied.  The simulated effects of cover crop treatments on soil profile hydrology variables such as runoff, evaporation, drainage and transpiration were evaluated as a fraction of the corresponding check treatment results.  A multiple regression equation was developed and used to estimate yield of a following crop based on climate, soil, cover crop biomass and termination timing variables from the simulated yield results of the study.