Study on Dissipation Dynamics of Thiamethoxam in Tea and Soil

The residual dissipation dynamics of thiamethoxam in tea and soil were investigated by the methods of high performance liquid chromatography and field trial method.The results showed that dissipation of thiamethoxam in tea was faster,but slower in soil.Dissipation of thiamethoxam in both tea and soil was fitted to the first-order kinetics.The half-life of thiamethoxam in tea and soil was 3.1 and 5.5 d respectively.Residues of thiamethoxam in tea and soil were dependent on application doses and spraying times.Application doses had the greater effect on residues of thiamethoxam in tea and soil.Residues of thiamethoxam in tea and soil appeared to increase with increasing application doses.Under the conditions of the same application doses,there were no significant differences between residues of thiamethoxam in tea of different spraying times.However,the residues of thiamethoxam in soil decreased gradually with the increase of spraying time.The significant differences were observed between residues of thiamethoxam in soil sprayed 1,2 and 3 times.