Behaviour of bispyribac sodium in soil and its impact on biochemical constituents of rice.

The present study evaluates the dissipation behaviour of bispyribac sodium in acidic soils and its effect on biochemical constituents of rice. Dissipation kinetics followed first-order kinetics and >75% of applied bispyribac sodium dissipated within 7 days after application. Half life of bispyribac sodium ranged from 4.06 to 13.93 and 3.19 to 11.95 days in 2016 and 2017, respectively at studied application rates. The amount of bispyribac-sodium adsorbed increased with increase in concentration of herbicide and log K_F of bispyribac-sodium was 1.528 µg^1−1/n g⁻¹ ml^1/n in studied silty clay loam soil. Terminal residues in rice grain were below the maximum residue limit (<0.01). Acetolactate synthase activity and total carotenoids decreases significantly as compared to control up to 30 days after bispyribac sodium application and thereafter it recovered with the passage of time. Total chlorophyll and total sugar content in rice leaves increased significantly and maximum increase was observed when treated with bispyribac sodium at 20 g ha⁻¹. Quality parameters, i.e. total protein and total sugars were not significantly influenced by application of bispyribac sodium. The use of bispyribac sodium at studied application rate in rice crop is safe both in terms of crop quality and food safety. [ABSTRACT FROM AUTHOR]