Cover Crop Strategies to Balance Corn Production and Environmental Stewardship.

Links between environmental degradation and agricultural practices have given rise to concerns about sustainability. Cover crops have been suggested as an alternative management practice to mitigate nitrate-N pollution of water resources and soil erosion. Research was conducted to examine the impact of cover crop strategies on water resources and corn (Zea mays L.) productivity across three environments in the upper Midwest. Combinations of cover crops were integrated into a corn-soybean [Glycine max (L.) Merr.] rotation to achieve multiple benefits: annual rye [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] and cereal rye (Secale cereal L.) for reducing nitrate-N leaching, crimson clover (Trifolium incarnatum L.) for improving soil fertility, and forage radish (Raphanus sativus L.) to alleviate soil compaction. Soil N and water balances were evaluated to determine cover crop effects on growth and yield of corn and ecosystem services. Soil type, precipitation, and air temperature influenced the establishment and effectiveness of cover crops in reducing nitrate-N leaching. Cover crops established more vigorously in warmer growing environments but not when combined with increased precipitation. Corn productivity by cover crop treatment varied least at the location with medium-textured loam soil and intermediate air temperature. Cover crops established greater canopy cover under soybean than corn in two of three locations. Cover crops seeded at the four-leaf collar corn stage produced greater end-season living canopy coverage compared to cover crops seeded at the dent stage of corn. Site-specific understanding of cover crop management is necessary for effective utilization and adoption of cover crops to balance environmental stewardship and corn production.