Study On The State Evaluation And Control Strategy Of Land Desertification In Beijing

Based on field research and the remote sensing image (2005a TM) interpretation, using multi-information of research area and existing research results (iccluding data of geology, geography, hydrology, meteorology, economy, human culture, etc.), with the help of GIS tool and some mathematical methods, such as probability, statistics, curvilinear estimation, logical analysis and analytic hierarchy process, the author evaluated the state of desertified land, analyzed the dynamic and cause of land desertification, proposed combating and controlling desertification advertising of Beijing.Land desertification evaluation result of Beijing indicated that Beijing have the desert lands 54621hm~2 up to 2005 years , the desert lands which are fixed sandy land all distribute on YongDing river, both side of ChaoBai river and WenYu, KangZhuang, DaSha river of Huairou and Miyun County, involving 11 County and 102 towns. The degree of sandy land is slightly desertification, the area of sandy land is 52181hm~2, The land use types of the sandy land include forest, grassland and land remained bare, and cultivated land which have a big area and distribute widely is potential sandy land of Beijng .The result about the Dynamic analysis of sandy land in Beijing express that, the sandy land of Beijing totally present to expansion tendency from 1949 to 2005, the desertification development velocity is 45 hm~2/a, the expanding rate is 1.08% annually. From last century 80's, the area of sandy land in Beijing is having decrease, especially in last 10 years, the sandy land of Beijing present to descend trend steadily, descending 3 percentage points about every 5 years. Currently, the desertification development velocity of Beijing is negative, sandy land development tendency from the last century of "break big in manage" change to "manage with break to hold mutually", the sand development tendency have already keep within limit.Natural and social-economic factors together made the desertification occurrence and development of Beijing. The geography characteristics and the anti-breeze eclipse of the soil are the geology condition to the desertification occurrence and development of Beijing.The variation of the weather is the main reason that induces the desertification, not reasonable artificial activity is the acceleration to the desertification process. The result about compares with climatic factors (from 1949 to 2006) in Beijing express that, in the short-term, the annual changes of temperature, precipitation, dryness indexes and gale days is basic to be in a normal scope, but the shortdated unconventionally change of annual mean temperature shows which is a sensitive climate factorshould to be pay attention. The main expression structures of the artificial factor which influences the Desertification are Excessive reclamation and grazing, excessive water using and exploring and constructing activity. The irrational growth of the population, the underground water level descend, the irrational land use structure, the irrational traditional agriculture management mode are the main reasons of the land desertification occurrence and development in Beijing. Among these factors, the leap of the population is the initial factor to the land desertification occurrence and development in Beijing.Finally, the author put forward the strategy of combating and controlling desertification in Beijing. It is, directing with the View of Scientific Development, persisting in Coordination Between Urban and Rural Areas, combining to defendence, treatment and use, taking science and technology as support, relying on the important ecological engineering, constructing the high standard system to combate and controll desertification, serving the goal of to build Beijing as a modern and international city, which have the fresh air, the beautiful environment, the good ecosystem and the Harmonious Human Settlement Environment. Concretely, "The mountain area conservation, the plain area control" is the ecosystem establishing general layout of Combating and Controlling Desertification in Beijing. Desertification control structure of the plain area is "three straps, two patchs, and many points". Special forestry and fruit industry, grass industry, livestock breeding, ecological tourism industry are the key to the deserticulture system construction. Safeguarding system construction is the fundamental security of ecosystem establishing and deserticulture system construction.