Johnsongrass control with herbicides prior to planting sorghum

Several herbicides were applied to emerged johnsongrass prior to planting sorghum on irrigated and dryland fields in 1972 and 1973. On the irrigated field, Roundup gave the best control; however, within 2 weeks after sorghum planting, regrowth infested all treatments, and another herbicide application was made. Following the second application, which killed the sorghwn, Roundup and Ansar 529-HC at 1 and 6 pounds per acre killed 90 percent or more of the johnsongrass...