Effect of weed management practices on growth and yield of transplanted rice (Oryza sativa L.) under system of rice intensification

Abstract

A field experiment was carried out in wetland farms of TNAU, Coimbatore during summer 2021 to evaluate efficient weed management practices for transplanted rice under the System of Rice Intensification (SRI). The treatments consisted of different combinations of weed management practices including herbicides viz., butachlor 1.25 kg ha-1 and bispyribac sodium 40 g ha-1, cono weeding and hand weeding and were compared with unweeded control. The predominant weed flora present in the experimental field was Echnichloa colona (L.), Echnichloa crusgalli (L.), among grasses, Cyperus difformis (L.), among sedges and Eclipta alba (L.), Ammania baccifera (L.), among broad leaved weeds. The results revealed that application of early post emergence herbicide bispyribac sodium @ 40 g ha-1 at 15 DAT + cono weeding at 30 and 40 DAT recorded lesser weed density (4.18, 2.88 no. m-2 at 40 and 60 DAT), weed dry weight (3.20, 1.61 g m-2 at 40 and 60 DAT) and higher weed control efficiency (82.1 and 93.6 per cent at 40 and 60 DAT) which resulted in increased number of productive tillers m‑2 (445) and filled grains per panicle (176). Application of early post emergence herbicide bispyribac sodium @ 40 g ha-1 + cono weeding at 30 and 40 DAT recorded higher grain and straw yields of 6975 kg ha-1 and 9905 kg ha-1, respectively. This treatment was on par with application of early post emergence herbicide bispyribac sodium 40 g ha-1 + cono weeding at 30 DAT and hand weeding at 40 DAT.