关键词: 土壤氮磷储量；水土保持；成土母质；土地利用；丹江口库区

Abstract: The Danjiangkou Reservoir, serving as the primary water source for the South-to-North Water Diversion Middle Route Project, plays a pivotal role in ensuring water security for water receiving areas. Nitrogen (N) and phosphorus (P), essential soil nutrients, are recognized as key contributors to non-point source pollution. Consequently, understanding the spatial distribution of soil N and P is critical for assessing eutrophication risk and guiding nutrient management within the reservoir region. To address this, the spatial variability of soil N and P storage, along with their relationships to natural and anthropogenic factors, were examined through field surveys and geostatistical analyses of 345 sampling sites across the reservoir and its upstream catchment. The results showed that: ①In the study area, the distribution trend of "high in the northwest and south and low in the east" was generally presented. The spatial structure of soil nitrogen storage was strong (nugget effect <25%), and the spatial variability of phosphorus storage was relatively more complex. ②The spatial distribution of N and P storage was strongly influenced by parent material and land use. Soils derived from carbonate and clastic sedimentary rocks contained significantly higher N and P storage compared to those from other geological substrates. ③From natural perspectives, sustained sediment renewal in rivers/lakes maintained relatively low nitrogen and phosphorus accumulation levels. From anthropogenic perspectives, long-term fertilization of upland fields and orchards led to significant nutrient storage aggregation, whereas wetlands and paddy fields exhibited comparatively lower storage due to pronounced nutrient leaching. Paddy field soils exhibited reduced stocks, primarily due to nutrient leaching and runoff. These findings offer a scientific basis for relieving nutrient loss risks and enhancing soil and water resource management, while also providing practical recommendations for optimizing land-use planning and fertilization strategies to reduce non-point source pollution.

Key words: soil nitrogen and phosphorus storage; water and soil conservation; parent material of soil; land use; Danjiangkou Reservoir Area