农业径流与土壤侵蚀是两种重要的非点源污染形式，坡地水土流失是磷素流失的重要来源。基于此，本文针对黄土高原，以渭北(南部沟壑区)淳化县泥河沟流域坡地果园为研究对象，依据野外实验观测、采样、室内分析，通过不同坡位、不同树龄、不同耕作管理条件下，根层土壤中五种主要形态磷素的分析，研究了坡地苹果园土壤中磷素的迁移及其空间分异特征，初步结果表明： 1. 坡地果园土壤耕层中，全磷、无机磷、溶解态磷和颗粒态磷主要以地表径流与土壤侵蚀方式流失为主，其中颗粒态磷是随地表径流流失的磷素中最主要的形态，有机磷则受地表径流影响较小。 2. 与其他形态磷比较，无机磷与溶解态磷表现出较强的垂直迁移特征，易发生渗漏流失。 3. 根据坡地果园土壤磷素流失状况，可大致将坡面划分为以下三个区域：坡顶为基本稳定区，坡中是严重流失区，坡底为沉积区。 4. 通过对不同土层中磷素含量比较，果园土壤中磷素含量随树龄增大而增加。 5. 果树根系层对无机磷和溶解态磷含量的影响比较大，除溶解态磷外，其他形态的磷素在水平方向上均没有明显规律。 6. 渗漏流失成为平地果园土壤中磷素流失的主要方式。 研究结果为评价本区苹果产业的迅速发展可能产生的磷素流失及对水资源的潜在危险提供了依据。

The agricultural runoff and the soil erosion are two important forms of non-point source pollution, the loss of soil and water in sloping field are the main reason for the lose of phosphorus. Based on this, the article in view of the loess plateau , take sloping land orchard in Nihegou basin, Chunhua County, Weibei (south gully region) as the research object. According to the experimental observation in wild, sampling, laboratory experimental, determine the content of five phosphorus fraction in different sloping land position, the different tree age, the different tillage management condition. Study the movement and spatial differentiation of phosphorus in the arable layer soil of sloping land orchard, the preliminary results showed that: 1. In the arable layer of sloping land orchard, the main runoff approach of TP,IP,DP and PP are surface runoff and soil erosion, among them, PP is the main phosphorus losses in the way of surface runoff, meanwhile ,OP is less influenced by surface runoff. 2. Compared to other phosphorus fraction, the IP and DP displayed stronger vertical migration characteristic, and leakage erosion is easy to take place. 3 According to the phosphorus runoff of sloping land orchard, approximately, we can divide the slope into following three regions: the top of slope is the basic stability region, the middle of slope is the seriously erosion region and the bottom of slope is the crystallizing field. 4. Through compare the content of phosphorus in different soil layer, we can find that the phosphorus content increases along with the tree age increases in the orchard soil. 5. The root system of apple tree layer influence the content of IP and DP greatly. Phosphorus has no obvious regulation in horizontal direction except DP. 6. The leakage erosion is the main way for the losing of phosphorus in the soil of flat land orchard. The findings provide basis for phosphorus erosion and the potential hazard of water resource caused by rapid development of local apple industry.