Abstract: Studies on the effect of palmitic acid, catechol and vanillic acid on behavior of Cd in soil show that the toxic concentration of catechol to rice plant is 100 mg·kg^-1, and that of vanillic acid is 500 mg·kg^-1.When the soil content of catechol is 5000 mg·kg^-1, the concentration of Cd in rice grain is reduced to 0.008 mg·kg^-1,and that in leached solution from soil column is lowered to 0.005 mg·L^-1.All of these three organic compounds can increase the proportion of soil organic bound Cd,which occupies 48.71% of total id when the soil is amended with 5000rug·kg^-1 catechol.

Key words: Palmitic acid, Catechol, Vanillic acid, Cadmium, Complexation, Fanhe River watershed, soil and water assessment tool, boosted regression tree, quantitative analysis