Cover Crop Research

Iowa Learning Farms has received several grants to research cover crops on farmer partner fields. The projects explore the benefits of cover crops on Iowa farmland using winter rye over eight years and using cover crop mixes.
 
Partners for the projects include the Iowa Cover Crop Working Group, Practical Farmers of Iowa, Iowa Department of Agriculture and Land Stewardship State Soil Conservation Committee, Leopold Center for Sustainable Agriculture, USDA-Natural Resources Conservation Service and Iowa State University farmer association farms.
 

On-farm Demonstration of Cover Crops

The study includes Iowa farmer partners using winter rye on a portion of their fields for five years. Findings from the farmer partners have been summarized into documents available for download:
 
Winter Cereal Rye Cover Crop Effect on Soil
Year 7 Update
Year 5

Winter Cereal Rye Cover Crop Effect on Cash Crop Yield 
Year 9 - December 2017
Year 8 
Year 7
Year 6
Year 5
 

Evaluating Cover Crop Seeding Techniques

Seeding Technique and Date Effect on Cover Crop Establishment - The project compared three different seeding techniques: above and below crop canopy using a high clearance interseeder and drilling after harvest. Evaluation of the techniques was completed through fall and spring biomass collection and crop yield. A no cover crop plot was included in the replications as a yield comparison check strip. The project started in Fall of 2014 and concluded with crop harvest in 2016.

 

Cover Crop Impacts on Crop Yield and Water Quality: Comparing Single Species to Mixtures

Cover Crop Impacts on Crop Yield and Water Quality: Comparing Single Species to Mixtures -  This study was conducted at six ISU research farms and the project compared three treatments: single species, mixture, and no cover crop. Before corn the single species is oats and the mixture contains oats, hairy vetch, and radish. Before soybean the single species is rye and the mixture contains rye, rapeseed, and radish.  Evaluation was completed through fall and spring biomass collection and crop yield. To evaluate impacts on water quality, suction lysimeters were installed at 5 sites.  Lysimeter pore water samples were taken and analyzed for nitrate once every two weeks over the growing season. The project started in Fall of 2013 and will continue through the 2019 crop season.