Author
LIEBMAN, M - IOWA STATE UNIVERSITY | |
GIBSON, L - IOWA STATE UNIVERSITY | |
HEGGENSTALLER, A - IOWA STATE UNIVERSITY | |
SUNDBERG, D - IOWA STATE UNIVERSITY | |
WESTERMAN, P - UNIVERSITAT DE LLEIDA | |
CHASE, C - IOWA STATE UNIVERSITY EXT | |
HARTZLER, R - IOWA STATE UNIVERSITY | |
MENALLED, F - MONTANA STATE UNIVERSITY | |
Davis, Adam | |
DIXON, P - IOWA STATE UNIVERSITY |
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/29/2007 Publication Date: 5/7/2008 Citation: Liebman, M., Gibson, L.R., Sundberg, D.N., Heggenstaller, A.H., Westerman, P.R., Chase, C.A., Hartzler, R.G., Menalled, F.D., Davis, A.S., Dixon, P.M. 2008. Agronomic and economic performance characteristics of conventional and low-external-input cropping systems in the central corn belt. Agronomy Journal. 100:600-610. Interpretive Summary: Agriculture in the Midwestern USA is characterized by heavy reliance on agrichemicals, widespread chemical emissions to water, and strong dependence on government subsidies. Diversified low-external-input (LEI) cropping systems offer important opportunities to reduce use of synthetic fertilizers and pesticides, but questions remain as their ability to maintain crop productivity and profitability. We conducted a 9-ha experiment in Boone County, IA, to compare a conventionally managed corn/soybean system with two LEI systems that included small grains (triticale and oat) and forage legumes (red clover and alfalfa) in addition to corn and soybean. Despite large reductions in N fertilizer and herbicide inputs, yields from the LEI systems matched or exceeded yields obtained from the conventional system. Weeds were controlled effectively in all systems. Without subsidies, net returns from one of the LEI systems exceeded returns from the conventional system. With subsidies, this advantage was reduced, but not eliminated. Labor requirements for the LEI systems were higher than for the conventional system. Our results indicate that certain LEI systems can be biologically and economically competitive with conventional systems in regions of high production potential. Technical Abstract: Agriculture in the Midwestern USA is characterized by heavy reliance on agrichemicals, widespread chemical emissions to water, and strong dependence on government subsidies. Diversified low-external-input (LEI) cropping systems offer important opportunities to reduce use of synthetic fertilizers and pesticides, but questions remain as their ability to maintain crop productivity and profitability. We conducted a 9-ha experiment in Boone County, IA, to compare a conventionally managed corn/soybean system with two LEI systems that included small grains (triticale and oat) and forage legumes (red clover and alfalfa) in addition to corn and soybean. Despite large reductions in N fertilizer and herbicide inputs, yields from the LEI systems matched or exceeded yields obtained from the conventional system. Weeds were controlled effectively in all systems. Without subsidies, net returns from one of the LEI systems exceeded returns from the conventional system. With subsidies, this advantage was reduced, but not eliminated. Labor requirements for the LEI systems were higher than for the conventional system. Our results indicate that certain LEI systems can be biologically and economically competitive with conventional systems in regions of high production potential. |