基于数字土壤系统的县域土壤磷素流失风险简化评估

摘要

County is the basic administrative unit in China. This paper explored a simplified method of soil phosphorus loss risk assessment at county scale in order to provide guidance for the county phosphorus risk assessment and production practices. Under considering the characteristics of the county scale, the paper simplified phosphorus index assessment method, and assessed phosphorus loss risk for Shunyi district based on digital soil system using GIS technology and pedometrics. The research results showed that the phosphorus loss in the study area presents higher level in the east and lower in the west, and zonal distribution along the rivers. The distribution pattern mainly was led by agricultural inputs. Risk of soil phosphorus loss was overall lower in the study area, but the moderate risk accounted for 30.05% of the total area. Phosphorus management should be strengthened and soil phosphorus loss should be prevented in the future. The simplified P index-based digital soil could reflect risk level of regional phosphorus loss, which can provide risk a reference for risk assessment for the county phosphorus loss.%县域是中国基本的行政管理单元,探讨县域尺度下土壤磷素流失风险评估的简化方法,旨在为县域磷风险评估和生产实践提供指导.该文在充分考虑县域尺度的特点,简化磷指数评估方法指标和评估过程,并以北京市顺义区为例,基于数字上壤系统,采用地理信息系统和计量土壤学技术,采用简化后的磷指数法对顺义区磷素流失风险进行评估.结果显示,顺义区土壤磷素流失的风险程度呈现东部高,西部低和沿着河流呈条带状分布的特征,这种分布特征在一定程度上说明了导致顺义区土壤磷流失的主要原因是农业投入,顺义区土壤磷素流失风险程度以低为主,但中等风险的面积占总面积的30.05％,今后应加强研究区磷素管理,防止土壤磷流失.基于数字土壤系统的简化磷指数法能够很好地反映待评估区域磷素风险程度,为县城磷素风险评估提供了参考价值.