| Abstract
| - Understanding and quantifying the adsorption and desorption of herbicides by soil is important forpredicting their fate and transport in the environment. Here we report a study concerning theadsorption and desorption, by four different soils, of imazosulfuron, 1-(2-chloroimidazo[1,2-a]pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl)urea, a new sulfonylurea herbicide. Both phenomenaare well-described by the Freundlich equation, which shows this herbicide to be little adsorbed byeach of the four soils investigated. The Freundlich adsorption constants, Kf-ads, ranged from 1.46 to3.02. Distribution coefficients between soil and water, Kd, measured on soils of different organicmatter contents and pH values showed an important effect of these two parameters on imazosulfuronretention. The Freundlich desorption data indicated that a significant amount of the imazosulfuronsorbed is not easily desorbed. The desorption process showed an evident hysteresis phenomenon,which may contribute to the persistence of imazosulfuron in soil. Keywords: Imazosulfuron; sulfonylurea herbicide; adsorption; desorption
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