RICE (ORYZA-SATIVA) WEED-CONTROL WITH SOIL APPLICATIONS OF QUINCLORAC

Field studies were conducted from 1988 to 1990 on a Sharkey clay to ev aluate residual weed control in rice with quinclorac applied PPI, PRE to dry soil, and PRE to moist soil. Quinclorac applied at 0.4 or 0.6 k g ai ha-1 PPI or PRE to dry or moist soil controlled more than 80% of barnyardgrass, pitted morningglory, and hemp sesbania without rice inj ury. Quinclorac applied at 0.3 kg ha-1 controlled these three weed spe cies substantially but inconsistently. No rice injury was observed fro m any quinclorac treatment. Except for one of three years when irrigat ion was delayed for 7 d after PRE application to dry soil, application timing did not consistently affect weed control or rice yield.