- Agronomic: corn
- Crop Production: cover crops, no-till, tissue analysis
- Natural Resources/Environment: carbon sequestration, soil stabilization
- Pest Management: allelopathy, competition, cultural control, mulches - killed, weed ecology
- Soil Management: nutrient mineralization, soil quality/health
This project compares the influence of single- and multiple-species cover crops on soil properties, weed community, and subsequent corn production. We will document effectiveness of 16 fall-seeded cover crops planted after soybean harvest on nitrogen and carbon additions to soil, weed community, soil residue cover, and subsequent corn yield.
With 23.6 million acres of annually planted row crops, Iowa leads the US in planted acres of corn and soybean, average yield per acre for corn and soybean, and average annual soil erosion rate. However, Iowa farmers planted only about 100,000 acres of cover crops in the fall of 2012. Increased utilization of cover crops in conjunction with reduced or zero till systems will greatly reduce soil erosion, and concomitantly improve soil quality, and increase nitrogen retention within farm fields and soil available water for subsequent crop use.
The majority of cover crop research done in the Corn Belt is with winter rye or other fall-seeded grasses. Our overall goal is to provide better options for fall-seeded cover crops, including species diversification, for Corn Belt farmers. We will document effectiveness of 16 fall-seeded cover crops, sole-crops, binary-, and trinary-mixes in zero tillage following soybean harvest. Cover crops tested in our project include crucifers (mustard family plants), legume, and cool-season grasses. Multiple-location, replicated field studies on university research stations will document nitrogen and carbon additions to soil, weed community, soil residue cover by cover crops, and subsequent corn yield. Multiple-location, replicated field studies on-farm will document performance of cover crops.
Dissemination of results and functions relating growing degree days to biomass, N, and C accumulation for the 16 cover crops will provide farmers, consultants, and action agency personnel science-based utilization and deployment of cover crops in the Corn Belt and American Midwest
Project objectives from proposal:
Outcomes from our project include increased knowledge by farmers and action agency personnel of cover crops and cover crop mixtures performance, influence on weeds, in-field nitrogen retention, and yield of the subsequent corn. Farmers and action agency personnel will be knowledgeable of advantages and disadvantages of solecrops in comparison with cover crop mixtures on weeds and subsequent corn yield. Farmers and action agency personnel will become familiar with a new potential broadleaf cover crop, camelina, and relative advantages and (if any) disadvantages of camelina as a cover crop compared to more commonly used species, especially winter rye.
The most important long-term outcome of cover crops research is to increase green cover on the landscape to improve soil quality, reduce nitrate loading to surface and ground waters, provide sustainable cultural strategies for improved pest management, and positively impact yield and profitability of corn-soybean systems in the Corn Belt. Farmers, action agency personnel, and research and extension personnel are our primary targets. Knowledge gained by targeted personnel is assessed by comparing survey results from previous cover crop meetings in Iowa with results from surveys conducted following the conclusion of our three-year project