Application of bispyribac-sodium provides effective weed control in direct-planted rice on a sandy loam soil

An increasing water crisis, as well as the unavailability and high cost of labor, in Pakistan has forced rice-growers to plant rice directly into the field. However, severe weed infestation causes disastrous effects on the productivity of this rice system. In this study, three herbicides (pendimethalin, penoxsulam and bispyribac-sodium) were evaluated for weed control in direct-planted rice on a sandy loam soil. Weedy check and weed-free plots were established for comparison. Weed infestation decreased the rice yield by 75.2%. However, the application of herbicides suppressed the weed infestation, with a simultaneous increase in the rice yield. The postemergence application of bispyribac-sodium was the most effective herbicide in reducing the total weed density and dry weight over the weedy check, followed by penoxsulam and pendimethalin, respectively. Bispyribac-sodium increased the number of productive tillers, 1000-grain weight, number of grains per panicle and grain yield over the control, as well as improved the water productivity and economic returns of direct-planted rice. The weeds' proliferation increased the number of unproductive tillers and decreased the plant height. In conclusion, the postemergence application of bispyribac-sodium can be used effectively to control weeds, increase water productivity and improve the economic returns and yield of direct-planted rice on a sandy loam soil in Pakistan.