Agronomic Stability and Resiliency of the Corn-Soybean Rotation in the U.S. Corn Belt
2022
- Department of Agronomy, UW Madison
Project Media
The corn-soybean rotation of the U.S. Corn Belt is the dominant cropping system. It is a relatively young cropping system that is currently challenged by many abiotic and biotic factors. A question often asked, “Is it sustainable?” Resilient, stable, and productive cropping systems are needed to endure increasingly frequent climatic extremes. Our objectives were 1) To identify superior corn-soybean cropping sequences for stability and resilience across environments, and 2) To explore the relationship between productivity, stability, and resilience of corn-soybean rotations. Productivity is the average yield across normal years. Stability is the minimal variability of yields across normal years. Resilience is the ability of a system to withstand a climatic crisis with high yields and not deviate during the crisis with the ability to recover from a crisis and the speed of this recovery. An experiment initiated in 1983 involving tillage and corn-soybean rotations was used to evaluate stability and resiliency. Crop rotations included continuous corn, continuous soybean, corn-soybean rotation, and 5-yrs corn followed by 5-yrs soybean. In every year all phases of the crop sequences was established. The rotation effect lasted two years for corn and slightly longer for soybean. Greatest yields were measured during first- and second-year corn and soybeans. The pattern for corn yield response to rotation phase is different than the pattern for soybean. First year soybean following 5-yrs of corn yields more than rotated soybean. In corn, stability was not affected by rotation phase. In soybean, stability decreases as rotation phase increases. The standard deviation range between rotation phases is + 15 to 17 bu/A for corn and + 5.1 to 5.6 bu/A for soybean. The resiliency of the corn-soybean yield response pattern is similar across rotation phase. Seasonal growing degree day accumulation does not affect grain yield as much as precipitation. Warm/dry stress years affect grain yield more than cool/wet years. For soybean, the year following a warm/dry stress year was better yielding than an average year. Management decisions involving cropping sequence should be based upon productivity rather than stability or resiliency.