Relationship Between Leaching Potential and Accumulation of Phosphorus in Paddy Soils

Phosphorus(P) in surface leaching from agricultural soils is a contributor to accelerating eutrophication of surface water.Prediction of P loss leached from the soil needs the knowledge of how soil P accumulation affects P concentration in drainage water or leachate.In this study,a simulated experiment was carried out to explore the relationship between leaching potential and accumulation of phosphorus in paddy soils.Results show that P concentration in soil solution increased with soil Olsen-P.A critical point of soil Olsen-P was found for loamy soil,loamy clayey soil and clayey soil,respectively.Above that point the potential of soil P release increased sharply with soil Olsen-P.When these soils were low in Olsen-P,the relationships between P concentration in soil solution and soil Olsen-P were quite similar and could be fitted with linear regression equations.The relationship for sandy soils could be expressed as a linear regression equation.Sandy soil was much greater than other soils in phosphorus release potential with a given soil Olsen-P.