Reduced chemical input cropping systems in the Southeastern United States: III. Economic analysis

This study evaluated the profitability of several cropping systems during a 10-year period of an experiment comparing rotations and levels of purchased inputs. Continuous corn or sorghum, corn/wheat-soybean (2-year), and corn/wheat-soybean/corn/clover hay (4-year) were managed with recommended fertilizer and pesticide rates and no-till planting (C) or with N from legumes, conventional tillage, and cultivation for weed control (L). Medium input management (M: medium rate of N and banded herbicides) was included during years 5 through 10. Generally, corn was the least profitable crop, regardless of input level or type of rotation. Rotating crops improved profit more than did adding inputs to continuous corn. With L, average annual profit was: continuous corn, -$64/ha; 2-year rotation, $135/ha; and 4-year rotation, $158/ha. With C, the 2-year rotation increased profit to $165/ha from -$119/ha with continuous corn. The increased profit with rotations was due to greater profits from wheat, soybean, and hay offsetting low or negative profit from corn. Sorghum (grown only in monoculture) was more profitable with L ($34/ha) than with C (-$20/ha). During the 6 years when all input levels were compared, the order of average profit was M>L>C with continuous corn. Generally, profit was not increased by M compared with L in the 2-and 4-year rotations. With L, the cost of weed control was 20% of that for C with corn and 44% with soybean. Cost of N from fertilizer was $0.66/kg, but cost of N from crimson clover (seed and planting costs) averaged $0.92/kg when clover was drilled, $1.27/kg when aerially seeded, and $0.16/kg when naturally reseeded.