Study On Soil Organic Carbon Storage With Its Spatial And Temporal Distribution In Tongyu

The rising of the greenhouse gas such like carbon dioxide caused the global warming, which is becoming one of the most important environmental problems.And it drove the attention of people all of the world.Research on the carbon cycle in all ecosystems is a significant content of global warming.And the carbon in soil play an important part in the cycle.As the most active part in soil carbon pool, soil organic carbon (SOC) is very significant.Tongyu couty is a momentous agricultural and stockbreeding base of Jilin province.With the growing of population, the intensity of people activity such like estrepement, overgrazing and disafforestation is much stronger than before.The emission of greenhouse gas is increasing steadily.And this caused the climate and environment of the region changing dramatically.At the same time,it bring the soil desertification, salinization, grassland degradation becoming more and more seriously.As the principal part of this process, research on soil organic carbon storage and its spatial and remporal distribution is of great meaning.This paper based on the NSFC item(named"Research on Foundation and Application of Eco-environment Digital Information System in the Southwest part of the SongNen Plain") of my supervisor Prof. Tang Jie.The passage estimates the the 0~1m and 0~20cm SOC by different soil types and different land use types (including the year 1989, 2000 and 2004) respectively by GIS tools.And then calculate the 0~20cm SOC proportion of 0~1m SOC in these two methods.In this process, the most pivotal of these methods is confirming the proportion of different soil types (or different land use types) and the average SOC densities.So the data collection of the area of different soil types (or different land use types) and the soil datas is the key to this process. Firstly, RS-GIS integration technique was used in this passage to land use RS dispelling of Tongyu in the year of 1989, 2000 and 2004.And then the land ues status was picked up and the land use figure was drew to gain the area of all land uses with its spatial distribution.Based on the analysis of the land use styles number model, it was concluded that the land use style changes mainly incarnated in the phenomenon of"four increases and four decreases". Four increases meant the increase of the area of infield, woodland, residential area and saline-alkali soil. Four decreases meant the decrease of the area of grassland, water area, desert and marsh. Thereinto the most increasing area is woodland, the area of saline-alkali soil is less; contrary the most decreasing area is grassland, the area of marsh is less.Different soil types'areas are from the vectorgraph of soil type figure drawing through the sofeware ERDAS IMAGINE.The soil data is from the soil samples testing by my supervisor's workgroup in 1998, 2005 and 2006. The lacking datas are collected by consulting interrelated literatures.The result shows that, by using the different soil types, the 0~1m SOC storage is 70,344,946.04t and the 0~20 SOC storage is 20,365,414.04t, which took up 28.95 percent of 0~1m SOC storage.And by using the different land use type , the 0~1m SOC storage in 1989,2000 and 2004 is 72,712,604.53t,68,622,104.00t and 70,924,932.23t respectively.With the 0~20cm SOC storages in 1989,2000 and 2004 are 20,136,603.81t,18,111,694.94t and 19,255,561.85t , they proportion of 0~1m SOC storage is 27.69%,26.39% and 27.15% respectively.The SOC storage reduced from 1989 to 2000, and rose up from 2000 to 2004.Secondly, the paper visual analyses the 0~1m and the 0~20cm SOC storages'spatial and temporal distribution in different soil type and land use types from 1989 to 2004.The result shows us that the highest SOC density area is assembling near by the Xianghai National Nature Reserve in Xianghai Mongolian Autonomous Village northwest Tongyu couty.The 0~1m SOC density and the 0~20cm SOC density in this area are both highest.The least area distributed in Wulanhua Town and Xinfa Village.The The 0~1m SOC density and the 0~20cm SOC density in this area are both lowest.Lastly, the research analysed the controlling effect of the physical matters, biologic matters and factitious matters to the SOC storage in Tongyu.The result figured out that the mainly factor to the SOC storage is omnifarious. It can be described as follows: the natural factor such as temperature, precipitation, vegetation types, soil quality, clay and mineral types, topographty and physiognomy character etc; the rising of the carbon dioxide consistence in atmosphere; the effect of land use and management such as the land assart, overgrazing and the agricultural managemental measure etc.This study based on the technique integration of RS-GIS-GPS, adopted multi-source RS or non-RS data and the existed soil sample testing datas, researched the SOC storage of Tongyu in different ways. And it gave out the spatial and temporal distribution of SOC in Tongyu. The methods of this study can be used in other areas in similar researches. The results are significative to solve the austere soil problems, to comprehend the climate changes, to improve the soil environment, to keep the steady development of economy and society.