|BASCHE, ANDREA - Iowa State University|
|ARCHONTOULIS, SOTIRIOS - Iowa State University|
|Sauer, Thomas - Tom|
|MIGUEZ, FERNANDO - Iowa State University|
Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2016
Publication Date: 4/26/2016
Publication URL: https://handle.nal.usda.gov/10113/5262855
Citation: Basche, A.D., Kaspar, T.C., Archontoulis, S., Jaynes, D.B., Sauer, T.J., Parkin, T.B., Miguez, F. 2016. Soil water improvements with the long-term use of a winter rye cover crop. Agricultural Water Management. 172:40-50. doi: 10.1016/j.agwat.2016.04.006.
Interpretive Summary: Climate change will cause significant problems for corn and soybean production in the Midwest. One approach to mitigate climate impacts is to utilize crop and soil management practices that enhance soil water storage, reducing the risks of flooding as well as 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 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 the cover crop increased the soil water storage capacity and did not reduce the water available for corn and soybean growth. This research indicates that the long-term use of a winter rye cover crop can improve soil water dynamics without sacrificing water availabilty or crop yield in corn-soybean crop rotations in the Midwestern United States.The impact of this research is that it can help to guide government support for farmer adoption of cover crops and should increase producer adoption of cover crops.
Technical Abstract: The Midwestern United States is projected to experience increasing rainfall variability. One approach to mitigate climate impacts is to utilize crop and soil management practices that enhance soil water storage, reducing the risks of flooding as well as drought-induced crop water stress. While some research indicates that a winter cover crop in maize-soybean rotations increases soil water availability, producers continue to be concerned that water use by cover crops will reduce water for a following cash crop. We analyzed continuous in-field soil water measurements from 2008 to 2014 at a Central Iowa research site that has included a winter rye cover crop in a maize-soybean rotation for thirteen years. This period of study included years in the top third of wettest on record (2008, 2010, 2014) as well as years in the driest bottom third (2012, 2013). We found the cover crop treatment to have on average significantly higher soil water storage from 2012-2014 when compared to the no cover crop treatment and in most years greater soil water content during the cash crop later in the growing season when a cover crop was present. We further found that the winter rye cover crop significantly increased the field capacity water content by 10-11% and plant available water by 21-22%. Finally, in 2013 and 2014, we measured maize and soybean biomass every 2-3 weeks and did not see treatment differences in crop growth, leaf area or nitrogen uptake. Final crop yields were not statistically different between the cover and no cover crop treatment in any of the seven years of this analysis. This research indicates that the long-term use of a winter rye cover crop can improve soil water dynamics without sacrificing cash crop growth in maize-soybean crop rotations in the Midwestern United States.