The Study On Land Use/Land Cover Change In The Agriculture And Pasturage Interlaced Zone Of Northern Shaanxi

Land resources are the material basis of the human existence, economic construction and social development , are the places and the carrier of all other resources existence。With the increased productivity and the advances of science and technology, irrational use and management, the result is that land resources are damage and waste a lot , and a series of environmental problems affect the stability of the economy and the development of human society. Land use / land cover are the key elements of land resources, with the rise of remote sensing technology and rapid development, people active take the remote sensing be used in the field of land resources, its application promote and facilitate the land resource research and development, and take the land use / land cover research into a new stage of development. Particularly the agriculture and pasturage interlaced zone in the north of our country where the ecological environment is very extremely, use the remote sensing to conduct dynamic monitoring for land use / land cover, there is a great significance for understanding the land use change patterns and the development .In this study, based on understanding the review of similar studies, useing of remote sensing tools, take the agriculture and pasturage interlaced zone of northern Shaanxi Dingbian County as the study area, use the maps of 1986 and 2003 as the data source ,with the professional image processing software ERDAS9.1 and ARCGIS9.2 support, monitoring and analysis the land use / land cover change .In terms of land use information extraction, first preprocessing the 1986 and 2003 remote sensing image, including image correction, mosaic, image enhancement and image subset and other processing to obtain a clear image of the study area .In order to classification the images and extraction information accurately. And then based on remote sensing spectral information and spectral band structure of the object in image, to set the threshold for extract the land type layer by layer, and mask out the type has been extracted to eliminate the impact of it, making the classification process more and more easy to extract the hierarchical classification of land use information. classification land hierarchical using the two-phase remote sensing image, the overall classification accuracy was 83.67% and 82.74% ,respectively, Kappa reached 82.17% and Kappa = 81.10%, respectively,. more than 70% which is the minimum requirements to classification standards. According to classification results of 1986 and 2003,we can analysis situation of land use, change of the land use and driving forces.The results show that the land utilization have changed a lot in Dingbian during the study period.Grass, water, dry land, irrigated land have increased ,Building land, grassland area have increased most; The area of grassland, waste land, bush forest land, forest land and sand land reduced, grassland and waste land reduced drastically. The total area of cultivated has increased. Which, by 2003 irrigated land increase 2183.04 ha, compared with 1986 increased by 40%, dryland increase 3472.68 ha, the increased irrigated land mainly come from woodland, farmland and grassland; the total forest area decreased by 2817.32 ha, the more forest land reduced, reducing 2476.71 hectares, the shrub land mainly change into grassland and grassland; the grassland area increased substantially, increased to 96,859 ha, is 1.59 times of 1986, its increase is mainly from sand , conversion of grassland and bare land; recent years, with the dam construction, a lot of new dam were made, maintenance and reinforcement a lot of dam, by 2003 the total water area of Dingbian County has increased to 2581.92 ha, there is a significant increase ,and the in ctease area is mainly from forest conversion, the conversion from forest land are 629.61 ha, including shrub land 327.99 ha and 301.62 ha forest land; building land area increased by 2757.69 ha, the increase area is 29%of1986, increase in the area of building land is mainly from arable land and waste land; There is a significantly reduce of waste land area,by 2003, sand land, bare land and grassland area decreased 6367.91 ha, 50,805.5 ha , 45,783 hectares, respectively, the sand mainly convert into the grass land and waste land,som waste land transform to woodland and farmland , with the reduction is accompanied by grassland, farmland and shrub land increased. natural environment of the agriculture and pasturage interlaced zone, the rapid industrialization and urbanization development, technological progress and national policies is the Impact of land use change .