洋河流域典型旱坡地土壤磷素淋失风险研究

Risk of Phosphate Leaching from Soil of the Typical Dry-slope Farmland of Yanghe Watershed

为深入研究土壤磷素含量与水体富营养化发生的关系,以秦皇岛洋河流域典型旱坡地为研究对象,采用网格法(5m×5m)采集表层(0～30cm)土壤样品31个,进行相关分析。结果表明,土壤有效磷、易解吸磷与地表径流中磷酸根态磷之间存在显著的相关性,一定程度上可用Olsen-P作为评价旱坡地土壤磷素淋失风险的指标;同时得出土壤Olsen-P含量为9.40mg·kg-1为洋河流域土壤磷素淋失的临界值,土壤Olsen-P含量为42.73mg·kg-1时,是土壤磷素淋失引起下游水体发生富营养化的临界值,并以此初步对洋河流域旱坡地进行了土壤磷素淋失风险评估。

At dry-slope farmland of the Yanghe watershed, Qinhuangdao city, 31 top layer soil samples （0-30 cm） were taken in a regular grid of 5 m by 5 m to study the relation of soil phosphours and water eutrophication. Correlation analysis of these data demonstrated that the correlation was significant among soil Olsen-P, CaCl2-P and Ortho-P of surface runoff and the Olsen-P of soil could be a assessment indicator of the posphate leaching risk from soil. The critical value of phosphate leaching from soil was 9.40 mg·kg^-1 Olsen-P of soil, and when water eutrophication the critical value phosphate leaching from soil was 42.73 mg·kg^-1 Olsen-P of soil. According to these, the risk assessment of phosphate leaching from soil of Yanghe watershed was researched.