Long-Term Corn and Soybean Response to Crop Rotation and Tillage

Long-term experiments are essential to understand how crop rotation and tillage practices affect corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production and its resiliency to variable weather conditions. A 28-yr rainfed experiment was conducted in Nebraska to evaluate continuous corn (CC), the corn phase of corn-soybean rotation (CS), continuous soybean (SS), and the soybean phase of corn-soybean rotation (SC), and tillage system (chisel [CH], tandem disk [DK], moldboard plow [MP], no-till [NT], ridge-tillage [RT], and subsoil tillage [ST]) on grain yield and yield stability. In 19 of 28 yr, CS yields were greater than CC, although the corn grain yield advantage in CS decreased as CC yield increased. Rotated soybean (SC) grain yield was greater than SS in 67% of cropping years, and similar in the remaining 33%. Stability analysis showed that all crop rotation and tillage combinations, except CH for soybean, resulted in stable grain yields across a range of seasonal weather patterns. Corn grain yields were affected by tillage in 29% of the years, while NT soybean resulted in consistently high and stable grain yields following an initial 11-yr lag period. We conclude that crop rotation has a greater impact on corn and soybean production than tillage in the western Corn Belt, although nearly all combinations can produce stable yields if well managed.