Effect of row spacing and weed management practices on dry direct-seeded spring rice

Abstract

Weeds are the major burden for rice-growing farmers in the case of direct-seeded rice due to the preemptive competition of weed in the species early seedling stage. A field experiment was carried out during the spring season in 2021 to evaluate the effect of different weed management practices and row spacing on dry directed-seeded spring rice under the Prime Minister Agriculture Modernization Project (PMAMP) at Rice Super Zone, Kanchanpur, Nepal. The experiment was laid out in a two-factorial randomized complete block design (RCBD) with twelve treatments and three replications. The highest number of effective tillers per m2 was obtained in weed-free plots (531.67), which is statistically similar to Pretilachlor fb 1HW (505.42). Row spacing of 10 cm showed a significantly higher number of effective tillers per square meter (521.94). A higher grain yield was observed in weed-free plots (6397.87 kg.ha-1), which is followed by Pretilachlor fb 1HW, which is statistically similar to other management practices except for weed check. All the management practices were found effective in reducing weed parameters such as weed density, weed dry weight, and weed index as compared to weed checks. A positive relation was recorded between plant height at 90 DAS and grain yield, thousand-grain weight, and grain yield, and a negative relation was recorded between weed density, weed dry biomass, and grain yield. It is recommended to apply Pretilachlor fb 1HW with 10 cm row spacing for effective weed control and to increase the yield of dry direct-seeded rice.