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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Western Corn Belt Cropping Systems on Agroecosystem Functions

Authors
item Liebig, Mark
item Varvel, Gary

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 25, 2002
Publication Date: March 1, 2003
Citation: Liebig, M.A., Varvel, G.E. 2003. Effects of western corn belt cropping systems on agroecosystem functions. Agronomy Journal. 95(2):316-322.

Interpretive Summary: Management practices that balance multiple functions of agroecosystems enhance agricultural sustainability, whereas those that focus on single agroecosystem functions do not. Understanding the effects of management practices on agroecosystem functions is essential to determine the relative sustainability of cropping systems. The relative sustainability of corn- based cropping systems in the Western Corn Belt was evaluated based on fou agroecosystem functions: food production, raw materials production, nutrient cycling, and greenhouse gas regulation. A simple indexing procedure was used to quantify performance across functions using data from a long-term cropping systems experiment in eastern Nebraska. Results from the evaluation indicated four-year crop sequences to possess the highest agroecosystem performance scores, followed by corn-soybean and continuous corn. Differences in scores among sequences were driven by a) the capacity yof four-year sequences to be highly productive, and b) a substantial negative effect of continuous corn at high levels of N fertilization on nutrient cycling and greenhouse gas regulation functions. Correlations between production- and environmental protection-related functions were negative, underscoring the importance of employing management practices that are productive, yet minimize harmful effects on the environment. Among the treatments analyzed in this study, four-year crop sequences appear to possess this capacity.

Technical Abstract: Agricultural sustainability is enhanced by management practices that optimize the performance of multiple agroecosystem functions. The performance of Western Corn Belt cropping systems was evaluated based on four agroecosystem functions: food production, raw materials production, nutrient cycling, and greenhouse gas regulation. A simple multiattribute ranking procedure was used to quantify performance across functions using data from a long-term (1983-1998) cropping systems experiment near Mead, NE. Treatments included in the procedure were four corn-based crop sequences (continuous corn, corn-soybean, and two four-year sequences) each at three N fertilization levels. Four-year crop sequences, which included an oat-clover intercrop, possessed the highest agroecosystem performance scores (avg. = 81.6) followed by corn-soybean (avg. = 79.1) and continuous corn (avg. =75.0). Differences in scores among sequences were driven by a) )the capacity of four-year sequences to be highly productive, and b) a substantial negative effect of continuous corn at the HIGH N-rate on nutrient cycling and greenhouse gas regulation functions. Nitrogen fertilization significantly increased agroecosystem performance between ZERO and LOW N-rate treatments, but had a negative effect above that level. Correlations between production- and environmental protection-related functions were negative, emphasizing the importance of employing management practices that are productive, yet minimize deleterious environmental impacts. Among the treatments analyzed in this study, four-year crop sequences appear to possess this capacity.

Last Modified: 9/2/2014
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