Study On The Impact Factors Of Soil Salinization Based On 3S Technology

The technology's development of the computer and network,the spatial information,and the global position system,make us can acquire and manage information quickly and roundly. Specially in researching on thematic information,we have a great breakthrough.These development of technology give a big help on the express of geography datas in spatial ,the analysis of geography and the forecast of them.Basin on this condition,this paper want to investigate the factors that are affecting the salinity.Soil salination often occurs in these area,where the climate is drought,the soil's evaporation is very intensity,and the water table is high and contain high dissolubility salt.It was occurred by certain climate, terrain, and hydrogeology, and they together influenced the water and salt movement. At the present time, soil salinization and secondary salinization have been an basilic issue of entironment ,that influence the production of industrial and agricultural seriously. Then comprehending these factors by the way of general-purpose,has a great sense of making reasonable measures to develop the governance.Firstly, this paper take the planet datas of 1989, 2001 and 2007 as basic data source, by the way of supervised classification methods, we get the distribution and the change informations about the soil salinity in 19 years, based on these information ,I make the analysis and researches.Then, combing the Remote sensing, Geographic Information System and the Global Positioning System, I analysis the process of soil salinization, the entironment about this domain, and confirm the form factors and the impact of these factors, moreover, analysis the nature and human factors,as follow. Here the entironment take a great part.As I analysis the change of climate, founding that this area's climate has always been a hige-temperatura,high evaporation and low precipitation, and through these, conclouding that in April is an important period of soil salinization.And analysis the time-varying of groudwater level, find that in April the groundwater level is relatively high in the year; then adoption the way of the spatial variation of groundwater level, find that in the eastern and southern regions of the study area , it is at relatively high water table.The changes of terrain have a big influence in salt-distribute'movement, and through the detailing analysis of the profile about the DEM and the Remote Sensing images, we found that the degree of soil salinity has a negative correlation with the terrain.Main human factors that affecting soil secondary salinization, such as population, economy, agricultural planting structure, agricultural productivity, were extracted .Through the exclusion of their analysis, combined with the areas of three periods of mild to moderate and severe salinity soil that derived from remote sensing images, a few important factors were selected and analyzed, the linear regression model of human factor for salinity changes was gained, the effective irrigated area has a greater correlation to mild saline land was concluded. Based on this, take residential areas as the center, different ranges were set to conduct buffer zone analysis, the maximum distance that human could affect soil salinization was obtained through the relevant salt index; Drainage density map of the study area was attained through the spatial analysis functions of ARCGIS, the buffer zone analysis of the drainage network was also implemented to get the effective impact distance of drainage networkConclusions can be drawn that:1. Through the information extraction of soil salinization of 3 periods of remote sensing image we found: the total area of saline soil of the whole study area increased gradually in 1989-2001,whereas it decreased in 2001-2007,and soil salinization of the study zone changed dramatically between 1989 and 2001.2. Through the study on the soil salinization natural factors of the study area found that: the climate is an important driving factors of soil salinization, the ratio between evaporation and precipitation increases rapidly in April and has a significant impact on the generation of soil salinization; groundwater level reaches the highest value in April during the year, and through the comparison between the spatial change of groundwater level and remote sensing classification chart found that most of the area of saline soil located in the region where the groundwater level depth range is from 2.4m to 2.5m; the analysis of terrain indicates that: dissolved salts along with water make horizontal displacement cause of rerrain , which has a significant impact on the accumulation of salinity.3. Through the study on the human impact factors of soil salinization in the study area found that : reasonable and effective model ,which is used to simulate the impact of human factors on soil salinization ,can not be established due to the lack of spatial statistic data;the analysis of affected spatial areas of residents shows that: the salt index changes dramatically during the 4km of human affected area ,whereas it conserves ; through the analysis of drainage density of the study area found that salt index changes greatly within the scope of 3km of the drainage network affected area.