To till, or not to till — that is the question

By Jodi DeJong-Hughes, University of Minnesota Extension

The new University of Minnesota publication “Conservation Tillage Systems for Corn Following Soybeans” was developed to assist producers and crop consultants in selecting a conservation tillage system for corn in a corn-soybean rotation.

This free online resource presents results of on-farm yield trials conducted across southern Minnesota in 2004 and 2005, and provides management tips for conservation tillage. The research was conducted by regional and local Extension educators and staff from the Monsanto Corporation, working with cooperating farmers.

Conservation tillage is defined as tillage systems that leave at least 30 percent residue cover on the soil surface after planting. Reduced tillage systems have benefits other than soil conservation, such as increased water infiltration, increased or sustained organic matter content, increased water-holding capacity and continued long-term productivity of the soil. They also require less capital investment in equipment and fewer field passes, which reduces the amount of labor and fuel used.

The findings: Climatic conditions varied across the state and between years during the study period. The findings we summarize show how conservation tillage can greatly reduce soil erosion, with minimal effect on crop yields and often at lower production costs than conventional tillage. We found that with appropriate adjustments to crop management, conservation tillage offers a low-risk means of achieving substantial reductions in sediment and phosphorus losses from cropland to streams, rivers and lakes.

Corn grain yields were significantly affected by tillage treatments at six of the 10 sites during the record-cool growing season of 2004. Average corn yields were largest at the sites that used chisel-plow-plus and strip-till during the 2004 trials.