[Factors dominating the sorption of bentazon in soils]

Adsorption isotherms of bentazon in six selected soils were measured by using batch sorption method. Meanwhile the mean partial free energy change of chemical in sorption process was also calculated. The results showed the adsorption isotherms of herbicide in five soils all were linear, distribution coefficients (Kd) ranged from 0.14 mL.g-1 to 0.31 mL.g-1, and the extent of soils adsorption the herbicide followed: Deqing paddy soil > Ji'an paddy soil(pH4.79) > Yuhang paddy soil > Lin'an red soil > Ji'an paddy soil(pH7.36) > Deqing loess. Investigation of Kd vs. properties of soils indicated that both of the pH and content of soil organic matters were dominating factors that affected the adsorption of bentazon in soils, and adsorption of bentazon in soils equated the partitioning of neutral and anion form bentazon into soil organic, which was independent of the natural of soil organic matters.