[Phosphate adsorption characteristics of paddy soils derived from main parent materials in Guangdong Province].

Isothermal adsorption experiment of phosphate on paddy soils drived from five different parent materials in Guangdong Province was carried out. The result showed that the adsorption data of different test soils could be simulated well by Langmuir, Freundlich and Temkin equations, and the Langmuir equation fitted the data best (correlation coefficient r: 0.995-0.999..). As a value of phosphate adsorption characteristics, the product of phosphate adsorption maximum (Xm)and sorption intensity factor(K) calculated by Langmuir equation could be a comprehensive index to characterize the potential phosphate adsorption by paddy soil, and could indicate the order of applying phosphate. The result also indicated that there exists two types of sorption region on the soils tested.