A Preliminary Study on the Characteristics of Phosphorus Leaching in Different Soils

The objective of this study is to investigate the characteristics and influencing factors of phosphorus leaching. The processes of phosphorus leaching of four typical soils (red soil, alluvial soil and purple soil) in Hunan are studied through the simulated leaching method by adding CaCl₂ solution with phosphorus of different concentration. The phosphorus concentration in the leaching liquid increase as phosphorus concentration in the eluent increased. The process of phosphorus leaching is carried out in stages. There is a critical point on every curve, the critical values of phosphorus leaching in 6 soils fluctuate between 9.854-65.372 mg·kg^-1. A big difference of critical values appears among different soils. There is a significantly negative correlation between the critical value of phosphorus leaching and Olsen-P, Fe-P, Al-P, the correlation coefficients are-0.950, -0.834 and -0.897 respectively. The characteristics of phosphorus leaching in different soils varies greatly, different evaluation standard of phosphorus leaching and agricultural management measures should be put forward in view of the different soil in order to reduce phosphorus leaching.