W. G. Palharini

Sweet Sorghum Establishment after Application of Residual Herbicides.

Imazethapyr, sulfentrazone, clomazone, diclosulam, trifloxysulfuron-sodium and trifluralin are residual herbicides commonly used for weed control in soybean or sugarcane crops. The sorghum crop implanted succeeding sugarcane, can be affected by the carryover effect of these herbicides. In this context, we aim with this work to evaluate the minimum period between application of herbicides with residual effect (imazethapyr, sulfentrazone, clomazone, diclosulam, trifluralin and trifloxysulfuron-sodium) and the planting of sorghum so that there is no impairment in growth and establishment of this crop due to the herbicide carryover effect. The experiment was installed in randomized blocks design with four replications, under field conditions. The herbicides were applied to the previously tillaged soil, with sorghum being planted 0, 14, 28, 42, 56 and 70 days after herbicide application (DAA). The percentage of germination was evaluated daily from planting, and 7, 14, 21 and 28 days after emergence (DAE) of each planting, the phytotoxicity was evaluated. Thirty five DAE of each planting season, ten plants were collected per plot for measurement of leaf area, fresh and dry mass of plants, leaves and stems. The minimum time interval for planting sorghum after application of these herbicides varies, but imazethapyr is highlighted by causing high and durable toxicity to sorghum even when planting sorghum after 70 days of its application.