Effect of three bio-fertilizers on degradation of chlorimuron-ethyl residue and rice growth

A plot experiment was conducted to investigate the effects of Nongda bio-agent (NBA), Shilu bio-fertilizer (SBF) and Nongda bio-fertilizer (NBF) on chlorimuron-ethyl residue degradation and rice growth under different concentrations of chlorimuron-ethyl. Results show that the three bio-fertilizers degrade 3 μg·kg^-1 and 6 μg·kg^-1 chlorimuron-ethyl residues in soils. Degradation rates of 6 μg·kg^-1 chlorimuron-ethyl by the three bio-fertilizers are respectively 61.5%, 58.3% and 62.7%, which are 17.8%, 14.6% and 19.0% higher than those under natural conditions. Plant height, ear length, seed setting rate and rice yield are significantly influenced by 0.03 μg·kg^-1 chlorimurone-thyl. The symptoms of phytotoxicity deteriorate with increasing chlorimuron-ethyl concentration. The three bio-fertilizers tends to eliminate negative effects on rice yield induced by 0.03 μg·kg^-1 chlorimuron-ethyl. However, though chlorimuron-ethyl phytotoxicity is not effectively degraded by the three bio-fertilizers with increasing application, phytotoxicity is significantly alleviated. Chlorimuron-ethyl bio-degradability by SBF is inferior to that by the other two bio-fertilizers. Application of the three bio-fertilizers guarantees safe production of rice at chlorimuron-ethyl application rate below 0.03 μg·kg^-1.