Performance of summer rice under different weed management practices

Abstract

During summer season of 2019-20, a field experiment was conducted to study the performance of summer rice under different weed management practices. There were total 9 treatments which includes-pre-emergence application of pyrazosulfuron ethyl 25 g/ha (T1) and oxadiargyl 90 g/ha (T2), T1 fb mechanical weeding at 40 DAT (T3), T2 fb mechanical weeding at 40 DAT (T4), T1 fb manual weeding at 40 DAT (T5), T2 fb manual weeding at 40 DAT (T6), mechanical weeding at 20 and 40 DAT (T7), manual weeding at 20 and 40 DAT (T8) and unweeded control (T9). Pre emergence application of herbicides (pyrazosulfuron ethyl 25 g/ha and oxadiargyl 90 g/ha) fb one mechanical or manual weeding at 40 DAT (T3 to T6) significantly reduced the population and dry weight of all the three categories of weeds in comparison with twice mechanical weeding and the unweeded control. The maximum weed control efficiency, leaf area index (5.33), crop growth rate (17.34 g/ m2/day), yield components, grain yield (5.10 t/ha) and straw yield (6.20 t/ha) of rice was recorded from twice manual weeding (T8) which did not vary significantly from T3-T6. Pre-emergence application of pyrazosulfuron ethyl 25g/ha fb mechanical weeding at 40 DAT resulted in the highest return per rupee invested (2.22 Rs.). There was no significant difference among all weed management practices regarding return per rupee invested except twice mechanical weeding which recorded significantly lower results. The weeds resulted 57.64% yield reduction in transplanted summer rice.