稻田土壤磷淋失潜力与磷积累的关系

Relationship Between Leaching Potential and Accumulation of Phosphorus in Paddy Soils.

了解稻田土壤磷积累对排水和渗漏液中磷浓度的影响,可为稻田磷素淋失预测提供依据。采用室内模拟方法,研究稻田土壤Olsen-P水平与土壤溶液中磷质量浓度之间的关系。结果表明,土壤溶液中磷质量浓度随土壤Olsen-P水平增加而增加,其中,黏土、壤黏土和壤土的Olsen-P超过临界值(分别为84、65和53 mg.kg-1)后,土壤溶液中磷质量浓度显著增加。土壤Olsen-P水平较低时,黏土、壤黏土和壤土的土壤磷素积累与排水和渗漏液中磷质量浓度之间的关系较为相近,这3类土壤溶液中磷质量浓度与土壤Olsen-P水平存在线性相关关系。而砂土溶液中无明显临界值,砂土溶液中磷质量浓度与土壤Olsen-P水平间也存在线性相关关系。相同Olsen-P水平时,砂质土壤磷淋失潜力明显高于其他土壤。

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.