Residue Management for Winter Wheat and Grain Sorghum Production with Limited Irrigation

Winter wheat ( Triticum aestivum L.) and grain sorghum [ Sorghum bicolor (L.) Moench] are extensively grown in the southern Great Plains on dryland and with irrigation, but yields often are low on dryland and irrigation water is limited. Because both crops respond well to timely irrigation, they sometimes are grown with limited irrigation. Thus, it was hypothesized that using limited irrigation for these crops would produce sufficient residues to increase soil water storage if conservation tillage practices were used. This study on Pullman soil (fine, mixed, thermic Torrertic Paleustoll) at Bushland, TX, determined the effects of residue management on soil water storage and use, yields, and yield components for wheat and sorghum grown in rotation with limited irrigation. Treatments were no‐tillage with standing (T 1 ) or shredded (T 2 ) residues, and no‐tillage after wheat and tillage after sorghum (T 3 ). Tillage did not affect water storage after wheat, but storage ranged from 68 mm with T 3 to 101 mm with T 1 after sorghum. Water use by wheat ranged from 93 mm with T 3 to 131 mm with T 1 , but tillage did not affect water use by sorghum. Tillage did not affect wheat yields because differences in soil water storage and use were small and irrigations minimized the water content differences. Tillage did not affect sorghum yields because using no‐tillage during fallow after wheat resulted in similar water storage in all cases. This study showed that practices that retain surface residues are effective for producing wheat and grain sorghum in rotation under limited‐irrigation conditions in the southern Great Plains.