Agronomic interactions, economics, and soil responses to cropping systems featuring different tillage, rotations, and chemical inputs.

摘要

Farmers, who adopt more diverse rotations, require more information on tillage x crop rotation interactions, agronomics, economics and soil physical characteristics. We evaluated yield interactions, economic profitability and soil physical characteristics under different tillage (moldboard plow, chisel, and ridge), rotation (continuous corn, soybean-corn, soybean-corn-corn, and soybean-wheat/clover-corn) and management systems (high and low chemical) in a 6-yr study at Aurora, NY. In moldboard plow, corn in soybean-wheat/clover-corn (9.2 Mg ha−1) and soybean corn (8.5 Mg ha−1 ) rotations under low chemical yielded greater than continuous corn under high chemical management (7.9 Mg ha−1). In chisel tillage, corn in the soybean-corn rotation yielded greater under high chemical (8.9 Mg ha−1) and similarly under low chemical (7.9 Mg ha−1) compared with continuous corn under high chemical management (7.6 Mg ha−1). In ridge tillage, corn in soybean-corn or first-year corn in soybean-corn-corn rotations yielded greater under high chemical (8.1 Mg ha−1) but less under low chemical (6.3 and 6.8 Mg ha−1, respectively) compared with continuous corn under high chemical management (7.5 Mg ha−1). The soybean-corn rotation under low chemical management resulted in the greatest net returns in chisel ({dollar}100 ha−1) and moldboard plow tillage ({dollar}148 ha−1). Growers who substitute soybean-corn and soybean-corn-corn (in ridge) rotations for continuous corn can maximize profits, and reduce the use of starter fertilizer by 33 to 50%, N fertilizer by 60 to 70%, herbicides by 60%, and insecticides by 65 to 100%. Ridge tillage had greater bulk density (1.32 g cm−3) and lesser infiltration rates (−ln 11.7 m s−1) and total porosity (0.38) compared with moldboard plow tillage (1.19 g cm−3, −ln 10.2 m s−1, and 0.42, respectively) at the 6th leaf (V6) stage of corn growth. During early grain-filling, bulk density and total porosity did not differ among tillage systems. The soybean-wheat/clover-corn rotation, which had the greatest earthworm densities (492 m−2 ), also had the greatest infiltration rates (−ln 10.4 m s −1) among rotations at the V6 stage. Tillage and rotation interactions did not exist, which indicate that 5-yr tillage effects on soil physical characteristics would be consistent across continuous corn, soybean-corn, and soybean-wheat/clover-corn rotations.