Study On Quantitative Retrieval Of Soil Organic Matter And Related Elements In The Black Soil In Songliao Plain Based On RS Data

The contradiction among population, resources, environment in the world is more and more serious. In the system of natural resources and eco-environment, the land resource is an important element, which concentrates and reflects many problems related with resource and environment. The quality of land becomes key issue concerned by governments and researches of various countries.Black soil belt in northeast China is one of the three large black soil belts in the world, mainly distributed in Heilongjiang and Jilin Province. The black soil belt plays very important rule in grain production in China. Because of natural and human factor acting on together, the soil degradation of the black soil occurs seriously, which attracts more and more attentions from people in the world.Due to taking time, exerting great effort and costing a lot, the traditional soil investigation method does not accord with the modern agricultural production. How to get the soil information within limited time became an important subject which soil researches have to resolve. The introduction of remote sensing technology is new field opened up for soil researchers. From 60's in the 20th century to now, with the development of remote sensing technology, especially hyperspectral remote sensing, it becomes possible for us to obtain repeatedly physics and geochemical parameter of the soil in short time and in wide area.The study of the characteristics of reflected spectrum of soil is the physical foundation of the soil remote sensing. Research results suggested that there are obvious relations between the spectrum characteristics with physical and chemical properties of the soil. A lot of physical and chemical factors such as moisture, soil organic matter, iron oxide and structure in the soil have obviously influence on soil spectrum. By characteristic analysis of the spectrum detected by Imaging Spectroradiometer and physics and chemistry of the soil, it is for us to assess the characteristic parameters of the soil.This paper is to combine physical and chemical property of the soil with remote sensing data and to quantitative retrieval of soil components by use of ASTER remote sensing data. ASTER remote sensing data processing at first, it is to transform DN value record in the image into apparent reflectivity. Through studying, comparing and analysis carefully spectrum characteristic of ASTER data of the black soil, Author obtain the diagnosis wave band of the organic substance of soil in the image:(0.63~0.69μm),(0.76~0.86μm).The characteristic control point in the spectrum is significant to discern organic substance in the black soil.Secondly, to fetch the logarithm with reflectance spectra value in the RS data in a step differential and two steps differential transform. These different transform improves sensitivity which reflects soil organic content, the total nitrogen and the total iron content in the black soil and to establish multivariate statistical regression equation among various mathematics transform of the reflect spectrum and organic content, total N and total Fe in the black soil. According to two respects of stability and prediction ability of the model, chooses optimum model as the predicting model. Thirdly, the quantitative retrieval based on RS data, organic contents are divided into 6 types, the total N content into 5 types and the total Fe content into 4 types in the black soil distributed from Beian City in Heilongjiang Province to Changchun City in Jilin Province. The result apparently shows the distribution trend and the content difference of organic substance in black soil and non-black soil by using RS data.Through contrast of the classification result, Author finds that distribution law of organic content and the total N content is very similar: the contents of organic and nitrogen in the northern area are higher than that in the southern area.This reason is that the temperature reduces gradually from north to south are in the black soil area, low temperature leads to inhibit of the microbial activity and creates the favorable condition for black soil formation. Another reason is the difference of intensity and time of the black soil reclaiming.At the same time, author chose a scene TM remote sensing data in 1986, carried out quantitative retrieval of organic content in the black soil. To compare the quantitative retrieval organic contents from TM data with that from ASTER data in 2000 in Helen area in Heilongjing Province, the total organic content in the black soil decreased obviously. The dynamic variation of the organic content is apparently showed by using different RS data.The research result of the paper can be acted as reference material of soil type investigation, sol degradation and agricultural production.