Study On Simulation Of The Absorbed Nitrogen And Phosphorus Quantity In Soil Of Hubei Province

The nitrogen and phosphorus element carried by soil erosion were the substantial clause which caused entrophication(for example lake, rivers and so on). Under the effect of the corrosive rainfall, the outflow quantity of the absorbed nitrogen and phosphorus which in the surface layer soil was increased, which caused the soil impoverishment and the entrophication tendency of the surface water was obvious day by day. Basin loses sand and the massive absorbed nitrogen and phosphorus were brought into the lake reservoir water body to pose the threaten seriously. The effective contamination control technology relied on the science reliable pollution load computation. It had the vital practical significance to estimated the absorbed nitrogen and phosphorus which caused by the soil erosion correctly.Hubei province was taken as the object of the study, first it gave the brief introduction to the natural environment of Hubei province(such as topography, rainfall, soil, vegetation, etc.). Then it simulated the soil erosion quantity of the multi-annual means (1989 - 2008). USLE was used as the basic theoretical foundation for the establishment of erosion models in this article. The high-tech such as GIS was also used as the technology platform to establish erosion modles. It gave a detailed description of the structure, for example, the ideas of modeling, the meaning and access to the six parameters that related to modle of the soil erosion and dealing with the photograph of parameters. It made a model experiment of soil erosion modles in Hubei. It deal with the collected data and got maps of the six-factor in the study area. According to the ARCGIS software, it obtained raster data of the soil erosion quantity by the subgraph multiplication. The estimate result was test by the soil erosion raster data of remote sensing investigation by Ministry of Water Conservation. Finally the load of the absorbed nitrogen and phosphorus in the studied area was carried on the simulation that was taken GIS as the foundation, then using the general detailed soil survey material to obtain the nutrients density chart. Under the premise of the ratio of silt loses moves and the ratio of the pollutant concentrates were confirmed. Total nitrogen, total phosphorus density and soil erosion quantity were substitution formula in order to compute the load of absorbed nitrogen and phosphorus,then the spatial analysis was carried on,which had provided the basis for the ecoregion of lake nutrients. The main conclusions were as follows: (1) The soil erosion model of the multi-annual mean condition in Hubei Province was studied and established. The soil erosion intensity rank which obtains using the USLE equation and the grid computational method was quite fit with the remote sensing investigation value which had the remarkable correlational dependence. It proved the feasibility of the establishment of the Hubei soil erosion model. (2) The load of the absorbed nitrogen and phosphorus in Hubei was simulated. The load of absorbed nitrogen and phosphorus of the basin was analysis. The overall distributed rule of the load of absorbed nitrogen and phosphorus and the soil erosion quantity was similar, which was taken Yangtze River, the Jianghan basin as the sand lost depocenter, droped from the south, north to middle and from west to east separately.In summary, this paper was established a soil erosion model of Hubei based on experience which was relatively crude but effective. The soil erosion quantity of the multi-annual mean condition in the research area was simulated. Then the load of the absorbed nitrogen and phosphorus in Hubei was simulated in order to the protection and the improvement of the basin water and soil resources were more effective and target-oriented. It provided the technical support for the sustainable development and the management decision of the basin ecological environment. Because the in-depth analysis and study of the ratio of silt loses moves and the ratio of the pollutant concentrates were not very enough, but also needs the further research.