Weed density and control efficiency of different weed control methods in transplanted rice in Nepal

This study was performed to evaluate the weed density and weed control efficiency (WCE) on transplanted rice under different treatments at a farmer's field, Bhanu-11, Rupakot, Nepal during Rainy season of 2017. Ten treatments (one manual weeding at 21 days after transplanting (DAT) (T1); two manual weeding at 21 and 42 DAT (T2); three manual weeding at 21, 42, and 63 DAT (T3); single cono weeding at 21 DAT (T4); double cono weeding at 21 &42 DAT (T5); triple cono weeding at 21, 42, and 63 DAT (T6); butachlor as pre emergence (T7); butachlor with single manual weeding at 21 DAT (T8); butachlor with double manual weeding at 21 & 42 DAT (T9) and weedy check (T10) were laid in randomized complete block designs (RCBD) with three replications. At 30 DAT, the highest weed density was recorded at unweeded check (T10) while it was the lowest at butachlor with double manual weeding (T9). At 60 DAT the effective weed control method on weed density was found to be double manual weeding (T2). At 90 DAT triple cono weeding (T6) was found to be more effective on controlling weed density (30) and was at par double manual weeding (T2), double cono weeding (T5) and butachlor with double manual weeding (T9). WCE was the highest in the plot treated with butachlor with double manual weeding at 21 and 42 DAT (T9) and the lowest in the plot treated with butachlor pre emergence (T7) at 30 DAT. At 90 DAT, WCE in the plot treated with triple weeding (T6) was found the highest (78.63%) and the lowest in the plot treated with butachlor as pre emergence (T7) (26.14%).