磷在全球范围内是限制性营养元素，也是作物发育所需的必须要素，研究土壤中磷的特性是为了保障农作物高产、维护国家粮食安全、控制土壤污染与缓解水体富营养化现象的重要体现。我国作为人口大国，粮食生产总量对我国经济发展起到制约性作用，为进一步科学管理土壤施肥措施，了解我国土壤中磷的含量与特点，研究我国现存的两种不同农业开发情形下的土壤磷素空间分布格局和迁移转化特征，即大规模农场经营模式和小农户分散经营模式，为探究不同耕作方式对土壤磷素的影响以及农业面源污染治理提供参考。本研究利用分布式生态水文EcoHAT-P模型，开展了对大规模农场经营模式代表地区三江平原和小农户分散经营模式代表地区贵州安顺屯堡在2010-2019年的磷元素迁移转化模拟，对近十年（2010-2019年）土壤磷酸盐、活跃态矿物质磷、稳定态矿物质磷、表层有机磷、随地表径流流失磷的含量进行模拟，依靠实地采样数据进行模型验证。计算得到不同形态的磷素时空分布特征，借助GIS技术对总磷、有机磷、无机磷以及流失磷进行空间和时间变化定量分析，阐述影响其时空分布和迁移转化的差异原因。主要的结论如下：

（1）大规模农场经营模式代表地区三江平原2010-2019年不同形态土壤磷的变化情况。结果表明2010-2019年三江平原磷酸盐呈上升趋势，十年内磷酸盐共增长了6.16万t，增幅为5.09%；活跃态矿物质磷上升，十年共增长了9.33万t，增长幅度为5.12%；稳定态矿物质磷呈上升趋势，十年内共增长37.97万t，增幅高达5.29%；表层有机磷十年内共下降了0.90万t，下降幅度为38.91%；随地表径流流失磷十年内共增长了9.51万t，增幅超过300%。利用实地采样数据对模拟结果进行验证，R2和RMSE分别为0.75和0.1，均表明本模型可以适用。

（2）小农户分散经营模式代表地区贵州安顺屯堡2010-2019年不同形态土壤磷的变化情况。结果表明2010-2019年安顺屯堡磷酸盐下降，十年内共减少了0.95万t，减幅为39.24%；活跃态矿物质磷下降，十年共减少了1.48万t，减少幅度为39.97%；稳定态矿物质磷呈下降趋势，十年内共减少3.04万t，减幅为15.59%；表层有机磷十年共下降了0.36万t，减幅为79.76%；随地表径流流失磷十年内共减少了0.81万t，减幅为79.61%。利用实测采样数据计算R2和RMSE分别为0.71和0.14，结果表明模型模拟精度可信。

（3）大规模农场经营模式下土壤磷容易形成累积效应，小农户分散经营模式下应注意对土壤磷的适当补充。对不同农业开发情形下不同形态土壤磷素空间变异规律进行分析，得到总磷、有机磷和无机磷的变化特征。其中总磷与无机磷的变化趋势大体一致，大规模农场经营模式三江平原的总磷和无机磷在北部、中部和东南部的耕地增加，南部、西部的林草地减少趋势，小农户分散经营模式安顺地区总磷和无机磷整体呈现林草地下降、水田和旱地基本保持不变的空间格局。有机磷在两种类型开发情形下均呈下降趋势，安顺屯堡地区下降幅度大于三江平原。两种农业开发模式下不同土地利用的总磷、无机磷含量排序均为：水田>旱地>草地>林地，有机磷含量排序均为：林地>草地>水田>旱地。

Phosphorus is a limiting nutrient element in the world, and it is also an essential factor for crop development. The study on the characteristics of phosphorus in soil is an important embodiment of ensuring high yield of crops, maintaining national food security, controlling soil pollution and alleviating water eutrophication. As a country with a large population, Chinese total grain production plays a restrictive role in Chinese economic development. In order to further scientific management of soil fertilization measures, understand the content and characteristics of phosphorus in soil, and study the existing two different agricultural development situations in China: the large-scale farm management mode and small-scale farmers decentralized management mode, to analyze the spatial distribution pattern, migration and transformation characteristics of soil phosphorus and so as to provide reference for exploring the impact of different tillage methods on soil phosphorus and agricultural non-point source pollution control. Based on the distributed eco hydrological EcoHAT-P model, this paper simulated the migration and transformation of phosphorus in Sanjiang Plain, a representative area of large-scale farm management mode, and Anshun Tunpu, the representative area of small-scale farmer decentralized management mode, from 2010 to 2019. The contents of soil phosphate, active mineral phosphorus, stable mineral phosphorus, surface organic phosphorus and phosphorus lost with surface runoff in recent ten years (2010-2019) were simulated, and the model was verified by field sampling data. The spatial and temporal distribution characteristics of different forms of phosphorus were calculated. With the help of GIS technology, the spatial and temporal changes of total phosphorus, organic phosphorus, inorganic phosphorus and loss phosphorus were quantitatively analyzed, and the reasons for the differences in their spatial and temporal distribution, migration and transformation were expounded. The main conclusions are as follows:

(1) Large scale farm management model represents the change of different forms of soil phosphorus in Sanjiang Plain from 2010 to 2019. The results show that the phosphate in Sanjiang Plain is on the rise from 2010 to 2019, with a total increase of 61600 tons, or 5.09%; The active mineral phosphorus increased by 93300 tons in the past ten years, with an increase rate of 5.12%; The stable mineral phosphorus showed an upward trend, with a total increase of 379700 tons in ten years, with an increase of 5.29%; In the past ten years, surface organic phosphorus decreased by 90 000 tons, with a decrease rate of 38.91%; Phosphorus loss with surface runoff increased by 95100 tons in the past ten years, an increase of more than 300%. The simulation results are verified by field sampling data, and R2 and RMSE are 0.75 and 0.1, respectively, indicating that the model is applicable.

(2) The scattered management mode of small farmers represents the change of soil phosphorus in different forms in Anshun Tunbao, Guizhou Province, 2010-2019. The results show that the phosphate in Anshun Tunbao decreased from 2010 to 2019, and 95, 000 tons in ten years, 39.24% in ten years; The active mineral phosphorus decreased by 148 tons in ten years, with a decrease of 39.97%; The stable mineral phosphorus decreased, with a total decrease of 34000 tons in ten years, with a decrease of 15.59%; The surface organic phosphorus decreased by 36 thousand tons in ten years, with a decrease of 79.76%; The phosphorus loss with the surface runoff decreased 81, 000 tons in ten years, with a decrease of 79.61%. Calculating R2=0.71 and RMSE=0.14 by using the measured sampling data and the results show that the simulation accuracy of the model is credible.

(3) Under the large-scale farm management mode, soil phosphorus is easy to form a cumulative effect, and small farmers should pay attention to the appropriate supplement of soil phosphorus under the decentralized management mode. The spatial variation of different forms of soil phosphorus under different agricultural development was analyzed, and the variation characteristics of total phosphorus, organic phosphorus and inorganic phosphorus were obtained. The total phosphorus and inorganic phosphorus in Sanjiang Plain increased in the north, middle and southeast of Sanjiang Plain, and decreased in the South and west of Sanjiang Plain. The total phosphorus and inorganic phosphorus in Anshun area showed the spatial pattern of forest and grassland decreasing, paddy field and dry land basically unchanged. Organic phosphorus showed a downward trend in both types of development, and the decline in Tunpu area of Anshun was greater than that in Sanjiang Plain. The order of total phosphorus and inorganic phosphorus content of different land use under the two agricultural development modes was paddy field > dry land > grassland > woodland, and the order of organic phosphorus content was woodland > grassland > paddy field > dry land.