Yield and Overall Productivity under Long‐Term Wheat‐Based Crop Rotations: 2000 through 2016

CORE IDEAS: Summer crop yields were greater when the summer crops follow wheat rather than following a summer crop Wheat yield was relatively lower in rotations where two summer crops are involved (four‐year rotations) compared with one summer crop (three‐year rotations) Wheat yields were relatively lower following sunflower than other summer crops Sorghum has greater yield potential in this environment followed by wheat and corn, and rotations that included sorghum following wheat (W–GS–F and W–GS–C–F) were the most productive. Crop rotation is a proven sustainable cropping system in dryland production. However, finding the most compatible crops, in terms of maximizing yield, quality, and profitability, is a continuous process. The objective of our study was to identify compatible crop sequences and evaluate the overall productivity of potential crop rotation systems in the central Great Plains. This long‐term study was conducted from 2000 through 2016 near Tribune, KS. Four summer crops [corn (Zea mays L.) (C), grain sorghum (Sorghum bicolor L.) (GS), soybean (Glycine max L.) (SB), and sunflower (Helianthus annuus L.) (SF)] along with winter wheat (Triticum aestivum L.) (W) were grown in one‐, two‐, three‐, and four‐year rotations, with most rotations including a fallow (F) phase. Rotations were W–C–SB–F, W–F, W–C–SF–F, W–GS–F, W–SF–F, and W–C–GS–F from 2000 through 2006 and W–C–F, continuous GS, W–F, W–GS–C–F, W–GS–F, and W–C–GS–F from 2008 through 2016. Both annual and average corn and grain sorghum yields were greater in rotations where the summer crops were preceded by wheat rather than another summer crop. Annual wheat yield did not differ across rotations but tended to be lower in the 4‐yr rotations where two summer crops were involved and lowest in the W–C–SF–F system. Grain sorghum had a higher probability for greatest yield. Overall, W‐GS‐F was the most productive rotation followed by W–GS–C–F. In semiarid regions where water is limited, dryland producers should make their decisions based on both crop yield potential and sequence that provide the best utilization of the most limiting resource.