Characteristics of Phosphorus Leaching Losses and Environmental Threshold in Red Paddy Soils

PurposeTo explore the characteristics of phosphorus leaching losses and soil phosphorus environmental threshold in red paddy soils under different phosphorus levels.

MethodWe collected paddy soil with three phosphorus levels (P1, P2 and P3), a soil column simulation experiment was conducted to study the spatial distribution characteristics of phosphorus in four soil profiles, as well as TP, TDP content, loss characteristics of soil leakage and put forward the environmental threshold value of soil phosphorus.

ResultThe contents of total phosphorus and available phosphorus in red paddy soil at different P levels were accumulated at 0-60 cm soil layers. In the soil profile, the phosphorus accumulation gradually decreased and tended to stabilize as the soil profile depth increases. The concentrations and infiltration loss of TP, TDP and PP in the leakage fluid of red paddy soil l with different phosphorus levels showed P3> P2> P1, which was consistent with the distribution of Olsen-P content in soil surface. The soil phosphorus threshold value of red paddy soil was 50.34 mg/kg.

ConclusionThere may be a risk of phosphorus leaching in red paddy soil in Central Yunnan, and the higher Olsen-P content was in the soil, the greater the risk of leaching was.