Effects of Western Corn Belt Cropping Systems on Agroecosystem Functions
2003
Liebig, Mark A. | Varvel, Gary E.
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 agroecosystem performance using data from a long-term cropping systems experiment near Mead, NE. Treatments included in the procedure were continuous corn (Zea mays L.) (CC), corn–soybean [Glycine max (L.) Merr.] (C–SB), corn–oat (Avena sativa L.) + clover [80% sweet clover (Melilotus officinalis L.) and 20% red clover (Trifolium pratense L.)]–sorghum [Sorghum bicolor (L.) Moench]–soybean (C–OCL–SG–SB), and corn–soybean–sorghum–oat + clover (C–SB–SG–OCL) each at three N fertilization levels (ZERO, LOW, and HIGH). Based on treatment averages of soil and crop indicators from 1983 to 1998, agroecosystem performance scores ranged from 66.6 to 77.3, with a least significant difference (LSD) between treatments of 2.2 (P < 0.05). Treatments with the highest scores included C–OCL–SG–SB/LOW (77.3), C–SB/LOW (76.9), CC/LOW (76.7), CC/HIGH (76.6), and C–SB–SG–OCL/LOW (75.3). Among these treatments, those fertilized at the LOW N rate attained high scores through moderate performance in all four agroecosystem functions. The CC/HIGH treatment, however, attained a high score solely through its superior capacity to be highly productive, as its scores for the two environmental quality–related functions were the lowest among all treatments. 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.
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