Labour-saving weed management practices in transplanted rice

Abstract

Field research was conducted during rabi season of 2011-2012 at Agricultural College and Research Institute, Killikulam, Tamil Nadu to evolve the labour-saving weed management practice in transplanted rice. The experiment was consisted of 12 treatments laid out in randomized block design with three replications. The treatments comprised of application of pre-emergence herbicides viz., oxadiargyl 80% WP @ 70 g ha-1, butachlor 50% EC @ 1.25 kg ha-1, metsulfuron methyl 10% + chlorimuron ethyl 10% WP @ 4 g ha-1, bensulfuron methyl 0.6% + pretilachlor 6% GR @ 660 g ha-1 on 3 DAT along with post-emergence herbicide 2, 4-D Na salt @ 1.25 kg ha-1 or hand weeding on 35 DAT. In addition, the rotary weeding and hand weeding twice on 15 and 35 DAT and weed free conditions were tested with unweeded check. The results revealed that pre-emergence application of bensulfuron methyl + pretilachlor at 660 g a.i. ha-1 on 3 DAT with one hand weeding on 35 DAT recorded significantly lower weed dry weight (37.80 kg ha-1) and nutrient removal by weeds (1.25 N, 0.13 P2O5 and 0.87 K2O kg ha-1, respectively). This treatment also recorded higher grain and straw yield (6710 and 7717 kg ha-1, respectively) with higher number of productive tillers m-2 (427), dry matter production (14668 kg ha-1) and N, P2O5 and K2O uptake of 93.88, 35.20 and 108.54 kg ha-1, respectively. Further the gross return, net return and B:C ratio were also higher with this treatment.