STUDY ON THE ENVIRONMENT EVOLUTION AND THE ANALYSIS OF CAUSES TO LAND SALINIZATION AND DESERTIFICATION IN SONGNEN PLAIN
The Songnen plain , rich in water and grass a century ago, is one of the biggest plains in China. Since the middle of the 20th century, agriculture and stock raising have been increased rapidly, and it had been built important industry base of energy sources. The land desertification, salinization, and grass degradation had been serious problems as the population increasing and economy developing, and many areas even had changed into slick spot of exposed salina. Based on the evolution of the geological history, integrated analysis on the causes of land salinization and salinized desertification had been done in Songnen plain by many factors, such as climate, humanity and global changes. Applied 3S technology to inspect the dynamic changes of salinized soil and water body, and the result showed that the increasing rate of salinization was 2. 38% per year from 1989 to 2001 , and water body decreased at the rate of 3. 81% . Evaluation of salinized desertification was done using GIS-EIS coupling technology, and the distribution digital map was drawn, which indicated that the area of salinized desertification in hinterland of Songnen plain was 36. 72% to the whole, and Da'an city was even 68. 37% . The cause of the land salinization in the Songnen plain was complex that it was neither from the irrigation nor from the eluviation of water to rock salt layer, it suffered from complex geo-environment evolution and social economy development. The abundant soda component in the plain was related to the weathering fragment of granite and volcanic rock, which mostly came from Daxing'anling mountainous region to the west. Since Pleistocene, the Western plain had been the depocenter and the area with the most serious salinization and salinized desertification in present period. Salt in the Songnen plain was enriched in the Holocene epoch, and alkalescence grassland was formed at the end of the epoch. Vegetation and soil covering were destroyed as the activity intensifying of human being, and resulted in the fasten development of salinization and salinized desertification, in which process the global warming effected to a certain degree.
NETL
NSTL
万方数据
维普
