將巴拉刈與十二種不同理化性質，且經過不同酸鹼處理，不同pH以及分別移除有機質、游離氧化鐵等之土壤做等溫吸附與脫附試驗。結果指出當移除有機質和游離氧化鐵時巴拉刈在試驗土壤上的吸附量並無顯著減少趨勢，此與有機質在粘礦表面的覆蓋情形以及離氧化鐵之含量有關。所有土壤的脫附量均以沒有有機質和游離氧化鐵時為最多，顯示純粹粘礦表面吸附的巴拉刈較容易脫附。比較三種供試土壤發現吸附量與脫附量會隨pH之增加而增加。吸附量方面以含有機質、游離氧化鐵較多的土壤會因pH之改變而改變較大，脫附量則以高嶺石較多的土壤因pH之改變而改變較大。有機質和游離氧化鐵在pH4時不能表現其在吸附上的貢獻，在pH9時則較能表現出因含量不同所造成的吸附量之差異。

The adsorption and desorption of paraquat on and from the soils had been carried out by using twelve different soils to which the pH had been adjusted, or the organic matter, free iron oxides had been removed. The results indicated that under the alkaline conditon, the higher the kaolinite, organic matter and free iron oxides contents, the higher the percentage of pH-dependent adsorption in the total adsorption. Apparently, there was a positive correlation between negative charges of the soils and the percentages of pH-dependent adsorption. The percentage of desorption of paraquat from pH-dependent charges was higher than from permanent charges. There were no significant differences between the amount of adsorption of paraquat on the soil before and after the organic matter and free iron oxides were removed. This was probably caused by the exposure of clay surface which was covered by the organic matter and free iron oxides in the original soils. The amounts of paraquat desorbed from the soils of which the organic matter and free iron oxides were removed, were higher than those of other soils. This indicated that the paraquat on the surface of clay minerals was easier desorbed than on the other surface. Under pH 4 condition, the contribution of organic matter and free iron oxides on the adsorption of paraquat was not significant. Under pH 9 condition, significant increase in the amount of adsorbed paraquat was found in the soils with the increase of organic matter and free iron oxides.