Yield and soil responses to adding wheat to a corn–soybean rotation

Abstract

Farmers are becoming interested in management practices that mitigate greenhouse gas emissions because of C trading initiatives. For example, farmers may be paid for no-tillage and use of cover crops, including winter wheat (Triticum aestivum L.). In 2012, a study was initiated at two locations in Ohio comparing corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] (CS) and corn–soybean–wheat (CSW) annual rotations under no-tillage with no wheat straw removal. The objectives were to compare: (a) plant stand and biomass at the early vegetative stage, and grain yield and (b) soil health indicators in the CS and CSW rotations. In 2019, soil organic matter was greater in the CSW rotation than in the CS rotation. Under CSW, soybean yield was significantly greater than in the CS rotation by 21 and 5% in the western location in 2016 and the northwest location in 2018, respectively. In the other six site-years, soybean yield was not significantly influenced by crop rotation. Corn yield at five of eight site-years was 17% lower on average in the CSW rotation compared with CS. Corn root and shoot biomass tended to be less in the CSW rotation than in the CS rotation. The negative effects of winter wheat on corn biomass and grain yield were probably a result of the no-tillage system without wheat straw removal, causing cooler and wetter soil conditions. Before entering into C agreements, farmers should understand the potential yield outcomes of no-tillage and winter wheat to ensure proper payment.