Abstract:sorption behavior of Zn in black soil and fluvo-aquic soil. The effects of pH and organic matter on theadsorption and desorption of Zn in the tested soils were analyzed. The results showed that both blacksoil and fluvo-aquic soil had strong adsorption capacity for Zn. The adsorption and desorption isothermsfitted the Freundlich model. The adsorption-desorption constants(Kf) of black soil and fluvo-aquic soilwere 1 882.03 and 1 546.66,respectively. The adsorption capacity of zinc increased with the rising ofpH when pH is between 4.6 to 7.4. After the removal of soil organic matters,Kfdecreased,the empiricalconstant(1/n) increased,and the adsorption process showed strong nonlinearity. Close-