Effects of Weed Control Treatments on Boro rice and Associated Weeds

Abstract

A study was conducted to examine how different rice varieties and weed management strategies impact the yield of Boro rice. The trail included two varieties viz. BRRI dhan28 and BRRI dhan29, and seven different weeding methods: no weeding, one hand weeding (HW) at 15 days after transplanting (DAT), two HW at 15 and 35 DAT, three HW at 15, 35 and 55 DAT, application of superhit 58 SL @ 0.2% (pre-emergence), application of livina 18 WP @1.5 g/L water (post-emergence) and rice residues 3 t ha^-1. The study was structured using a Randomized Complete Block Design (RCBD) and replicated thrice. The findings exposed that ten families were represented by fifteen weed species that infested the experimental plots. Density and dry weight of weed was not notably affected by rice varieties. At 35 and 55 DAT, three HW at 15, 35 and 55 DAT produced the lowest weed density (0.83 m^-2), (1.16 m^-2) and weed dry weight (0.19 g), (0.33 g). In interaction, three HW at 15, 35 and 55 DAT recorded least weed density (0.66) and (1.00) at 35 and 55 DAT. BRRI dhan29 produced the maximum number of total tillers hill^-1 (9.61), effective tillers hill^-1 (9.00), panicle length (22.10 cm), grains panicle^-1 (126.75), harvest index (47.09 %) and grain yield (4.71 t ha^-1) compared to BRRI dhan28. Three HW at 15, 35 and 55 DAT resulted maximum number of total tillers hill^-1 (10.50), effective tillers hill^-1 (9.40), panicle length (22.16 cm), grains panicle^-1 (118.56) and grain yield (5.39 t ha^-1). BRRI dhan29 along with three HW at 15, 35 and 55 DAT recorded maximum grain yield (5.55 t ha^-1). The study suggests that conducting three rounds of HW at 15, 35 and 55 DAT could be the most efficient method for both weed management and achieving a higher grain yield in Boro rice.