Date of this Version
Leopold Center for Sustainable Agriculture, 2016 Project Summaries. Competitive Grant Report E2013-19. This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/leopold_grantreports/504
Increased attention is being paid to cover crops as an option to reduce water pollution and decrease soil degradation in Iowa. More producers are experimenting with cover crops to increase soil productivity. However, when this project began there was little research to demonstrate the long-term impacts that cover crops have on crop yields. There were no estimates to quantify how much environmental benefit a cover crop could provide in terms of erosion and soil carbon changes. Such estimates are beneficial to demonstrate the long-term improvements that a cover crop affords in Iowa, particularly for corn-soybean rotations where the winter planting window is narrow, presenting a significant short-term challenge for producers. Using a cropping systems model such as APSIM (Agricultural Production Systems sIMulator) can offer estimates of potential benefits for farmers and policy makers which might take many years to observe in a traditional field trial. The objectives of this research were to:
• Measure crop growth and soil properties at a representative corn-soybean field site with a winter rye cover crop to provide specific parameters necessary to establish and test APSIM and to analyze field data for treatment effects of the cover crop.
• Use APSIM simulations to estimate the impact of long-term cover crops on soil carbon, soil erosion, soil water dynamics, and average main crop yields as well as cover crop impacts following more variable rainfall seasons, a projected climate change impact for the Midwest United States.