Abstract: In this paper,the rhizosphere effect of desorption of adsorbed Cu previously in the Quaternary reddic paddy soil (QP),Lateritic red soil(LR),Quaternary red earth (QR) and White bleaching paddy soil(WP) were investigated. The results showed that the adsorbed Cu could be divided into the easily desorped Cu (Cuedes),which could be desorped by 0.1M KNO₃,and the difficultly desorped Cu (Cuddes),which would be desorped by 0.1M HCl. As the adsorption of Cu increased,the desorption percentage of Cuedes increased,while that of Cuddes decreased. For Cuedes,it was less in rhizosphere soil than in bulk soil,the rhizosphere effect of samples was shown as QP>WP>LR>QR,and the mean desorption percentage of easily desorped Cu were in the order of QP<WP<LR<QR. For Cuddes,it was much in the rhizosphere soil,the rhizosphere effect was shown as WP>LR>QP>QR,and the mean desorption percentage of difficultly desorped Cu were in the order of QP>WP>LR>QR. The total desorption percentage of samples were QP>WP>QR>LR. The increase of Cu adsorption in rhizosphere was mainly attributed to the increase of difficultly desorped Cu.

Key words: Desoiption, Rhizosphere effect, Ea ily desorped Cu, Difficultly desorped Cu, Desorption percentage