Production of Corn and Sorghum Grain in Double‐Cropping Systems1

Abstract Double‐cropping systems involving no‐till planting are becoming popular in the southeastern USA, but adequate management practices have not been developed. Therefore, this study was conducted to determine the effects of the following tillage systems. Corn [Zea mays (L.)] and grain sorghum [Sorghum bicolor (L.)] were planted without tillage following winter wheat [Triticum aestirum (L.)] or barley [Hordeum vulgate (L.)] and with conventional tillage following previous summer crop at two locations in Georgia for 4 years with and without irrigation. Corn and grain sorghum yields did not differ significantly for conventional tillage and no‐till plantings made on the same date. No‐till corn and grain sorghum produced higher yields when early planted (after small grain for forage) than when late planted (after small grain for grain). Irrigation increased conventionally tilled corn yields by 31% (at Experiment) and grain sorghum yields by more than 20%. The smaller increases observed for irrigated early‐planted no‐till corn and grain sorghum were attributed to a higher soil water content on nonirrigated no‐till. Irrigation did not increase yields of late planted no‐till corn and grain sorghum due to interfering biological factors.