The adsorption and leaching of pesticides in soils are important evaluation index which can be used to describe the migration characteristics in soil. In this study, the adsorption and leaching of bifenox in different soils in China were conducted by oscillation equilibrium experiment, soil TLC and column leaching. The results showed that bifenox in the above soils were better fitted by the empirical Freundich adsorption isotherm. The adsorption constant （Kd） in Jiangxi red soil, Taihu paddy soil, Northeast China black soil were 20.2, 146.1 and 240.1. The extent of bifenox adsorbed by soils followed： Jiangxi red soil〈Taihu paddy soil 〈Northeast China black soil. The soil organic matter content was the dominant factor which affected the adsorption of bifenox in soils. Based on the calculation of free energy of soil adsorption, charges of free energy （AG）in Jiangxi red soil, Taihu paddy soil, Northeast China black soil were -18.86 ,-23.17 and-23.66 kJ.mol-1, the bifenox adsorption by soils belonged to spontaneous process. The bifenox adsorption by soils belonged to physical adsorption with charges of free energy less than 40 kJ·mol-1 In all the kinds of experimental soil, bifenox showed comparatively low mobility and leaching degree. The soil organic matter content and solubility of bifenox were considered as the major factors which affected the adsorption and leaching of bifenox in soils.
Ecology and Environmnet