Efficacy of integrated weed management practices on weed dynamics and productivity of black rice in Nagaland

A field experiment was conducted during kharif season of 2021 and 2022 at the experimental site of School of Agricultural Sciences (SAS) Nagaland University, Medziphema. Main plot comprised of four integrated weed management namely W1, weedy check (control); W2, hand weeding (15 and 30 DAS); W3, pretilachlor @ 1.0 kg/ha (PE) fb HW at 40 DAS; and W4, pretilachlor @ 1.0 kg/ha (PE) + bispyribac sodium @ 25 g/ha (PoE) at 20 DAS while four genotypes, viz. C1, Chakhao Poireiton (Check); C2, Chakhao Amubi; C3, Wairi Chakhao and C4, Khurukhul Chakhao under sub-plot and was laid out in split-plot design (SPD). A total of 11 different species of grasses, sedges and broad-leaved weeds was recorded from experimental field. At 60 DAS 2 hand weeding at 15 and 30 DAS recorded the lowest density and biomass of grasses, sedges and broad-leaved weed which was closely followed with application of pretilachlor @ 1.0 kg/ha (PE) fb HW at 40 DAS. Chakhao Poireiton and Wairi Chakhao among the genotypes recorded the lowest weed density and biomass respectively. Highest weed control efficiency and lowest weed index was revealed with two hand weeding at 15 and 30 DAS. Weedy check (control) recorded lowest growth, yield attributes and yield while maximum result was exhibited with two hand weeding at 15 and 30 DAS and was closely with application of pretilachlor @ 1.0 kg/ha (PE) fb HW at 40 DAS. Among genotypes, Chakhao Poireiton and Wairi Chakhao recorded the highest and lowest growth, yield attributes and yield respectively.