Remote Sensing Change Detection On Soil Salinization And Driving Force Analyses

Soil salinization is getting the world's attention for its bringing dangerous to the social economy, environment and agricultural eco-system. Applied remote sensing technology which is characterized by its macroscopically, integrations, dynamic and speediness to analysis characters, distributions, dynamic changes, and degree of salinization is very important to control over the further expanding, degradations of soils and sustainable development and rational planning of agricultures.It has been investigated and examined a large number of field dada on the spot like meteorological, hydrological, spectral and social materials, and evaluated quantitative assessment on the study area by using remote sensing image processing technology and geographic information system space analysis technology. It has been evaluated and presented the changes of arid zone salinization on time and space scale. Comprehensive assessment method has been held on driving forces of study area and scientific criterion about controlling over policies on agricultural sustainable development has been provided with some experiences. . The main aspects of the paper as follows:1. The fundamental idea of salinization dynamic change detection in this paper is that firstly using 30-year satellite images like MSS in 1972 ,TM in 1989 and ETM+ in 2001 of study area author has synthesized the different images through image sharpening and principle component analysis in near-red and visible light bands and then select supreme amount of information in assembled bands and found out that TM4,K-L2,K-T3 is the best band compounding mode after that classified the images respectively by using Bayesian algorithm in supervised classification. The classification results were over 90%.2. Taking full advantages of RS and GIS on geosciences to calculate area changes of different saline soils, arable lands, waste lands and water. Salinization change regulation in study area during30 years has been analyzed. It includes area change, salinization change degree and analysis of trends in range amount of time scale.3. The forming of salinization is a land degradation form which caused by the different environmental factors affection with human activity. The process and mechanism of salinization is complex so that hereby author tried to find way to the driving factors of salinization of study among30 years from 1972 to 2001.(1)Climate factors: Ugan-Kucha delta oasis is part of mainly arid area of our country there the dryness and evaporations are so strong which causes the ground water and the salt in the soil coming up and gathering on the surface. The drier the climate is the stronger the salt gathering and thicker the salt gathering bed.(2)Geological conditions: There are tertiary stratum salty calcium around basin and most of them are outcrops that means after rain there considerable amount of salt with water in the flow to the plain area which causes more salinization.(3)Hydrological factors: Saline lands have been distributed in the arid zones to some extend where mineralized under ground water are close to ground surface and this is the main factor of causing salinization. In the study area most of the underground water do not come out by flowing on ground but by evaporation and gathered on surface.(4) Social factors: Secondary salinization is caused by human irregular usage of land resources, ignorance of saline land chemical regulations and roughness on the water functions etc. Human activity effect the land in two ways like improving or degrading.The forming of salinization in the arid zone has its natural forces like climate, geomorphology, hydrology, soil condition and human social factors etc. The main reason for secondary salinization is of human activity. In this study, author tried to evaluate the salinization information based on change detection in 30year time period and discusses its causing factors. The purpose of research on salinization is that controlling effectively and using the land resources sustain ably. Irrationality on using water resources in arid and semi-arid zone is the main cause of sail salinization. So the concept of human is the fundamental of controlling the degradation. Establishing harmony between human and land, starting from the irrigation construction rebuilt water recycling system, implementing comprehensive controlling and regional controlling in the same time, presenting pertinence and maneuverable controlling suggestions.