Tillage Effects on Grain Yields in a Wheat, Double‐Crop Soybean, and Corn Rotation

Abstract

AbstractCrop rotations in conjunction with the appropriate tillage system can be an important means for enhancing crop yields in the southeastern USA. The objective of this study was to determine the grain yield response in a wheat (Triticum aestivum L.), double‐crop soybean [Glycine max. (L.) Merr.), corn (Zea mays L.) rotation for different tillage sequences of conventional tillage (CT) and no‐tillage (NT). The four tillage sequences were; (i) continuous NT for all three crops; (ii) wheat CT, soybean NT, corn NT; (iii) wheat CT, soybean NT, corn CT; and (iv) continuous CT for all three crops. A field experiment was conducted for 3 yr on a Pacolet sandy clay loam (clayey, kaolinitic, thermic Typic Hapludult) and an Aycock fine sandy loam (fine‐silty, siliceous, thermic Typic Paleudult) at North Carolina Piedmont and Coastal Plain locations, respectively. Notillage corn and soybean yields were greater than those in CT systems every year at the Piedmont location. Averaged over a 3‐yr period, these yield increases due to NT were 32 and 43% for corn and soybean, respectively. Corn and soybean yields were less affected by tillage at the Coastal Plain location, with NT yields greater than CT yields in only one year out of three for each crop. In general, wheat yields tended to be lower in a NT system at the Piedmont location, averaging 9% lower than CT wheat over a 2‐yr period. Yield increases for NT corn and soybean were attributed primarily to greater soil moisture availability as a result of reduced runoff. Tillage in the previous crop/year had little effect on grain yields.