DISSIPATION AND RESIDUE OF BISPYRIBAC-SODIUM IN DIRECT-SEEDED RICE AND PADDY FIELD

摘要

An experiment was conducted to investigate safety of bispyribac-sodium application on direct-seeded rice and paddy field by determining its residues in water, soil, rice plants, husked rice and rice hull. Its dissipation in water, soil and rice plants was also evaluated by the first-order kinetics. The residues of bispyribac-sodium in water, soil, rice plants, husked rice and rice hull were all undetectable (<0.05 mg kg~(-1)) at the harvest time, and the residues were below the maximum residue level recommended by Ministry of Agriculture of the People's Republic of China (0.1 mg kg~(-1)). The half-lives in water, soil and rice plants were within the range of 3.0-3.3d, 2.8-3.1d and 2.6-6.7d, respectively. The high dissipation rate and the low residue level of bispyribac-sodium suggest it to be safe for humans and animals as well as the environment when it is sprayed on direct-seeded rice at the recommended dosage.