Impact of different crop-establishment methods and weed management practices on productivity of lowland rice (Oryza sativa)

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, during winter (rabi) season of 2011–12 and 2012–13 to evaluate different crop-establishment methods and weed management practices in lowland rice (Oryza sativa L.) in strip-plot design with three replications. The experiment consisted of 3 establishment methods, viz. conventional planting (C₁), system of rice intensification (SRI) marker planting (C₂) and SRI machine transplanting (C₃) assigned in horizontal strips and six weed management practices, viz. conoweeding 4 times at 10, 20, 30 and 40 days after transplanting (DAT) (W₁), pre-emergence (PE) pretilachlor 50% EC @ 0.75 kg/ha + conoweeding at 20 and 40 DAT (W₂), PE pretilachlor 50% EC @ 0.75 kg/ha + early post-emergence (EPOE) bispyribac-sodium 10% SC @ 20 g/ha (W₃), PE pretilachlor 50% EC @ 0.75 kg/ha + EPOE bispyribac 10% SC @ 20 g/ha + conoweeding at 40 DAT (W₄), EPOE bensulfuron + pretilachlor @ 0.66 kg/ha + conoweeding at 30 and 40 DAT (W₅) and unweeded control (W₆) were allotted in vertical strips. The results revealed that machine planting resulted in significant increase in growth characters, viz. plant height and leaf area index; yield attributes, viz. tillers/m², panicles/m², grains/panicle and yields (grain and straw) of rice. With regard to weed management practices, conoweeding 4 times at 10 days interval starting from 10 DAT exhibited maximum values of growth and yield components and recorded higher grain yield. The combination of mechanical transplanting with conoweeding four times at 10 days interval starting from 10 DAT registered significantly higher growth characters and yield attributes, which in turn exhibited higher grain yield, which was comparable with mechanical transplanting with pretilachlor (0.75 kg/ha PE) + bispyribac (20 g/ha EPOE) + conoweeding at 40 DAT.