Land Desertification Dynamic Monitor And Its Driving Power Analysis Based On 3S In Northwest Area Of Liaoning Province

Desertification is one of the most serious problems of environment andsocial economy, which heavily does harm to all aspects of both natural and socialeconomy. The North-west Liaoning province is on the south-east of Keerqinsand-land where the desertification is rather serious in China.The desertificationissue not only influences the developments of regional agriculture, stockbreedingand rural economics but also endangers peoples' life, therefore, the study on thedynamic change process and formation mechanism of desertification which canguide preventing sand-wind & desertification and protecting environment ineffect has important effect on prompting the continual development ofagriculture and Liaoning province economy.This paper discussed types, classification standards and survey methods ofland desertification. Both two ways of manual image interpretation andautomatic computer classification based on the expert design tree model are usedto obtain desertification info. The Desertification Distribution Maps are plottedbased on the RS images in 1970s, 1988 and 2000 and other techniques such asGIS and GPS, and overlapped to analyze the dynamic change processes ofthe desertification in North-west Liaoning province during the past 25 years.Furthermore, field check and geology survey are the important ways to confirmthe interpretation results and that the samplings test are used to probe into thedriving mechanism of desertification. In addition, the application of Markovchain model on predicting the development of desertification in future isdiscussed, which is a new domain on desertification research and a spark of thisarticle, too. It is shown by studies that: (1) The types of desertification in North-west Liaoning province arecomposed of aeolian desertification (1965.044 km~2), water-erode desertification(25800 km~2) and salinization desertification (83.16 km~2).There are aeolian desertification lands in North Zhangwu county andKangping county, of which 47.4% are the moderate desertification and 44.0% areare the slight;there are water-erode desertification lands in Chaoyang, Jianping,Lingyuan and Kazuo counties, of which 62.0% are slight and 29.5% aremoderate;a few salinization desertification lands are fragmentarily in Zhangwucounty, most of which are in Xinglong and other fields between Weitang riverand Liuhe river.(2)The desertification lands diminished from late 1970s to 2000 and thedevelopment of desertification is controlled so that the environment improved,and there are parts of quick sands turn to stable sand hills and vegetation coverratio turns larger.All kinds of severe desertification lands turned into slight, such as severe tomoderate and slight, moderate to slight and so on. However, there are ratherslight desertification lands turned into moderate and severe and there is still aserious problem that the main desertification lands types turned into moderatefrom slight and moderate in 1970s.From 1970s to 1988, the desertification lands were in a state of reverse andthe reverse velocity is fast, but the slight desertification lands were in state ofdevelopment in typical study area. From 1988 to 2000, the velocity of reversediminished fast, and the desertification was in a state of slight development.Although the slight and salinization desertification lands diminished, themoderate, severe and very sever desertification lands increased so that there wasa potential threat of the increasing of very severe desertification.(3) Based on the application of Markov chain model on predicting thedevelopment of desertification in future, the severe and very severedomestication lands will continuous increase in the ratios of lands, and the ratiosof the slight and the salinization lands will diminish until the state reaches thebalance. The moderate desertification will diminish before increasing, but theincrease will be more than diminishing at last. When the balance state appears,the ratio of desertification will reach 39.415 % from 37.97% at present, so thedevelopment of desertification is unpromising.(4)The driving force of desertification is the result of effects of nature,human being activities and social economy. Abundant materials, speciallandforms, hydrology condition and dry-cold climate with full wind are the baseagent forces of development of desertification. Modern agricultural, overlyherding and lumbering activities and other mining activities lead the weakbiogeocenose to the vicious circle by means of destroying vegetation, descendingproductivity and making lands desertification.Between the factors hereinbefore, weak environment is the necessarycondition which enhance the possibilities of the origin and development ofdesertification, however, driving force of human being is the main factor ofdesertification development.