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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #321581
Title: Soil erosion and nutrient runoff in corn silage production with kura clover living mulch and winter rye

Author
item SCHWAB, ARTHUR - University Of Wisconsin
item Jokela, William
item ALBRECHT, KENNETH - University Of Wisconsin

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Corn harvested for silage is a productive forage crop, but one that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare how the use of a living mulch or a cover crop in corn silage production affected nutrient runoff losses, soil properties, and silage yields. Corn without a cover crop was compared to corn planted into a Kura clover living mulch, a winter rye cover crop planted after corn silage harvest, and a combination of Kura clover and rye on a silt loam soil with 8 to 15% slope. The three Kura clover or rye cover crops reduced runoff by 50 to 68%, erosion by 77 to 81%, phosphorus loss by 80 to 94%, and nitrogen loss by 80 to 84%. Greater vegetative ground cover was the most important factor in reducing soil and nutrient losses in the cover cropped treatments. Both corn and rye had lower yields when grown in Kura clover living mulch, but this would be partially offset by lower fertilizer requirements. This information will be useful to forage producers and consultants who advise producers on ways to reduce soil erosion and the runoff of phosphorus and nitrogen.

Technical Abstract: Corn (Zea mays L.) harvested for silage is a productive forage crop, but one that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare the effects of using Kura clover (Trifolium ambiguum M. Bieb.) living mulch or winter rye (Secale cereale L.) cover crop in corn silage production on nutrient runoff losses, soil properties, and forage yields. Corn without a cover crop was compared to corn planted into a kura clover living mulch, corn with a winter rye cover crop planted after silage harvest, or a combination of kura clover and rye. Runoff was generated with a portable rainfall simulator five times over the course of a year on loess soils with 8 to 15% slope. Kura clover living mulch reduced water runoff by 50%, soil loss by 77%, and P and N losses by 80% relative to monocrop corn. Rye reduced water runoff by 67%, soil loss by 81%, P loss by 94%, and N loss by 83%. The rye-Kura clover combination reduced runoff by 68%, soil loss by 77%, P loss by 94%, and N loss by 84% relative to monocrop corn. Dissolved reactive P, NH4-N, and NO3-N were often, but not always, higher in monocrop corn. Treatment differences in soil loss and total P and N losses were due to a combination of differences in runoff amount and concentration, while differences in dissolved P and N were driven primarily by differences in runoff. Greater ground cover, as well as soil disturbance from rye planting, were associated with improved infiltration and reduced soil and nutrient losses in the cover cropped treatments. Both corn and rye had lower yields when grown in Kura clover living mulch, but this would be partially offset by lower fertilizer requirements.