Corn Residue Removal Effects on Soybean Yield and Nitrogen Dynamics in the Upper Mississippi River Basin

Abstract

Considerations for using corn (Zea mays L.) residues for biofuel should include impacts on the subsequent soybean [Glycine max (L.) Merr.] crop. We used the Agricultural Policy Environmental Extender (APEX) model to study the effects of: four rates of corn residue removals, 0%, 40%, 60%, and 80%, across site-specific conditions of two land types, highly erodible land (HEL) and non-HEL; three soil textural classes, clayey, loamy, and sandy; and the four soil hydrologic groups, A, B, C, and D, on soybean yield and nitrogen (N) dynamics, for 3703 farm fields within the Upper Mississippi River Basin. Overall, residue removal reduced soybean yield, N fixation, uptake, losses, and soil storage by 8%, 6%, 7%, and 5%, respectively. There is a positive tradeoff of residue removal, that is, it reduces the pool of nutrients available for loss, which resulted in a 9% decline in N losses when compared to no residue removal. Corn residue removal-induced reduction in soil organic N storage could affect the magnitude of the soybean N credit, implying that increased fertilization rates could be needed to sustain corn productivity in corn/soybean rotation systems. Responses were however subject to site-specific conditions, key considerations when determining residue removal thresholds.

Keywords:

• corn residue removal
• biofuel
• soybean
• APEX
• nitrogen dynamics

Notes

This article is not subject to U.S. copyright law.

This study was funded by Texas AgriLife Research (Texas A&M University System) and the United States Department of Agriculture, Natural Resource Conservation Service. We gratefully acknowledge the technical assistance of Theresa Pitts in performing the APEX model simulations.