Identification of Phosphorus Loss Spatial Features in Typical Land Use Patterns Coupled with Remote Sense and Soil Analysis

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The soil phosphorus (P) assessment is of great significance for agricultural non-point source pollution management in watersheds. Many of current studies provided data with limited accuracy and at relatively small spatial scale, due to the low spatial resolution of available remote sense data. This study used solid pollutants loss equation and high-resolution remote sense data source to determine the spatial characteristics of P loss, and then identified the critical polluted areas and corresponding underlying surface conditions within each land use type. Results showed that non-eroded region and slightly loss region covered more than 65% of the entire area. Although the severely-eroded region only accounted for 12.8% of the area, this region was distributed in the vicinity of downstream of two major inflow drainages. Hence, the harmful effect of this region on the watershed environment should not be neglected. The P loss varied significantly among different land use types, including forest land, arable land and orchard land. The forestland exhibited the lowest loss intensity, while the arable land exhibited the highest loss intensity. And the variation degree of P loss intensity within orchard land was probably greater than the other two land use patterns. Furthermore, this diversity in P loss largely resulted from different underlying surface features including topography, vegetation status, and key soil properties. The result from this study is suitable for practical use in different management strategies for non-point source pollution (NPS) management.