Cropping System and Tillage Effects on Available Soil Water and Yield of Grain Sorghum and Winter Wheat

Wheat (Triticum aestivum L.) in the central or southern Great Plains is grown in a 2‐yr wheat‐fallow (WF) cropping system or with grain sorghum [Sorghum bicolor (L.) Moench] in a 3‐yr wheat‐sorghum‐fallow (WSF) system. Tillage during fallow causes loss of crop residue and soil water. Long‐term studies were conducted at Garden City and Tribune, KS, to determine the effects of cropping system and reduced tillage on available soil water and yield of dryland winter wheat and grain sorghum. Conventional (CT), reduced (RT), minimum (MT), and no‐tillage (NT) systems were compared in WF and WSF. These treatments also were compared with CT in sorghum‐fallow (SF), continuous sorghum (SS), and continuous wheat (WW). Reductions in tillage resulted in increased available soil water and yield. Reduced tillage resulted in increased WF yields at both locations, while WSF wheat yields were increased at Tribune. Sorghum yields were more consistently increased by reduced tillage at Tribune. Sorghum‐fallow yields were higher than WSF sorghum yields at Tribune. Wheat‐fallow yields usually did not differ from WSF wheat yields at either location. Sorghum yields in WSF exceeded SS yields 67% of the time at Garden City. At Tribune, WSF‐RT yields exceeded SS yields 73% of the time, while WSF‐CT yields were no better or less than SS yields 60% of the time. Continuous wheat yields were less than other wheat yields 98% of the time. In terms of soil water storage and yield, the WSF system is appropriate for both locations, and is more effective when combined with reduced tillage, particularly at Tribune.