Effect of long-term fertilization on K+ desorption kinetics of noncalcareous fluvo-aquic soil

The characteristics of K+ desorption kinetics on noncalcareous fluvo-aquic soil under long-term fertilization condition were studied using the liquid flow technique.The results indicated that: 1) There were great differentia on K+ equilibrium desorption time and quantity among the different treatment,respectively.K+ equilibrium desorption quantity was closely related with CEC and kaolinite content;2) Long-term fertilization caused a discrepancy on desorbing velocity,which were also related with clay content,CEC and kaolinite content;3) There exist differentia in different reaction phases on K+ desorbing percentage,e.g.whose desorbing percentage rose fast at initial phase,but with high clay content;among different treatments;4) There was a linear relationship between desorption velocity and the reaction time(lnt),and desorption velocity was closely related with soil clay content;5) First-order kinetic equation was the best model for K+ desorption and the K+ desorption was controlled by the diffussion process.