Allelopathic Effects of Residues of Fimbristylis dichotoma Along with Manures and Fertilizers on the Weed Growth in Boro Rice

Currently, the rice-growing system seeks a biological solution to reduce the negative impacts of chemical herbicides because it is heavily reliant on these for weed control. This is where allelopathy comes in; it's a potential substitute for conventional weed management strategies in rice cultivation by making use of allelopathic plant residues. In the study we used Fimbristylis dichotoma residues with several organic sources of nutrient to measure the integrated effect of manures, fertilizers, and Fimbristylis dichotoma residues on weed growth in boro rice field. Two rice varieties viz., BRRI dhan29 and BRRI dhan89; and six treatments total viz., Control (T1), Residues @ 3 t ha-1 + Recommended doses of inorganic fertilizers (T2), Residues @ 3 t ha-1 + Tricho-compost @5 t ha-1 (T3), Residues @ 3 t ha-1 + Tricho-compost @1.5 t ha-1 + 25% less than recommended doses of inorganic fertilizers (T4), Residues @ 3 t ha-1 + Tricho-compost @2.5 t ha-1 + 50% less than recommended doses of inorganic fertilizers (T5) and Residues @ 3 t ha-1 + Tricho-compost @3.75 t ha-1 + 75% less than recommended doses of inorganic fertilizers (T6) were taken. In the experiment, at 25 DAT (days after transplanting), BRRI dhan89 had the highest weed density (35.0) when no residue was applied, and BRRI dhan29 had the lowest (18.00) when 3 t ha-1 F. dichotoma residue with Tricho-compost @ 1.5 t ha-1 + 25% less than recommended doses of inorganic fertilizers were applied. At 55 DAT, BRRI dhan89 had the highest weed density (19.66) when no residue was administered, and the lowest (10.66) when 3 t ha-1 F. dichotoma residue was applied along with Tricho-compost @ 1.5 t ha-1 + 25% less than recommended doses of inorganic fertilizers. When it came to dry weight, at 25 DAT, BRRI dhan89 had the highest weed dry weight (3.76 g) when no residue was applied, and BRRI dhan29 had the lowest (1.72 g) when 3 t ha-1 F. dichotoma residue with Tricho-compost @1.5 t ha-1 + 25% less than recommended doses of inorganic fertilizers were applied. At 55 DAT, BRRI dhan89 had the highest weed dry weight (2.29 g) when no residue was sprayed, and the lowest (1.46 g) when 3 t ha-1 F. dichotoma residue with Tricho-compost @ 1.5 t ha-1 + 25% less than recommended doses of inorganic fertilizers were applied. The study's findings suggest that applying F. dichotoma residue and incorporating Tricho-compost @ 1.5 t ha-1 + 25% less than the recommended amounts of inorganic fertilizers may be able to suppress the growth of weeds and could a package in biological weed control strategy.