A Study On The Land Use And Desertification Dynamic Monitor And Its Driving Mechanism Based On The RS And GIS In Agriculture And Pasturage Interlaced Zone Of Northern Shaanxi

The land use / land cover and desertification change of agriculture and pasturageinterlaced zone of northern ShaanXi of China in the past 15 years was investigated throughland use /land cover classification of three sets of the multi-temporal remotely sensed data ofTM, acquired on August 2, 1986 as the middle of 1980s, July17,1992(two images) and July30,1994(one image) as the early of 1990s, and August 9,2000 as the later of 1990s and the 21strespectively. Based on the RS and GIS, this research attempted to monitor on the land use/land cover and desertification process and spatial heterogeneity dynamic change, open outthe driving mechanism from 1986 to 2000 in the region. The main conclusions are as follows. i Multi-sensor imagery amalgamating, matching, and enhancing are very important inremote sensing image processing, which improved the spatial resolving evaluation, amendedthe image environment that can be use to distinguish from other upper objects, enhanced theland use/land cover and desertification information characteristic, also. These entire remoteimagerytreated can improved the precisionof land use classification. ii The total area of plantation was decreasing ３５９９２９．２hm2, which was caused by dryfarmland decreasing from 1986 to 2000 mainly. With the rapid increasing of population,mining activities have been identified as the sole cause of rapid change of dry farmland ,andthe degree of the fragmentation of its patches had highly increasing. The decreasing area hadmainly converted to wasteland, saline land and sand as a result, which happened in thevicinity of the Mu Us Desert edge, especially, Yuyang district, Shenmu, Hengshan, Jingbian,Dingbian county el.at. were more severer. The area of forest land and grass land each has increased by 132074.6 hm2 and 78590.9　ｈｍ２. Landscape pattern analysis found out that forest and grass land patches increased withfragmentation process, which became more scatter in the spatial. As we monitoring, theincreasing area rooted in plantation and sand land that were returning cropland to grassland orwoodland and sandy rehabilitated where happened in the southern loess gully and hilly areasand in the northwest sandy area, which was in accordance with the regional environmentalcharacteristics and the land policy "returning farmland to woodland or grassland andrehabilitating desertification". With the rapid developing of city based and economic of the study area, the scale ifurban and country area had highly enlarged 19519hm2 from 1986 to 2000. But theconfiguration and layout of construction going to rationalization and standardization, whichexpanded outward based on the primary city. The body of water had hardly changed through monitoring, but the river showedshrinking by 6980.7 hm2 at the past nearly 15 years, on the contrary, beach and reservoir areawith the great augment, each increased by 9967.5hm2 and 980.1hm2 from 1986 to 2000. Thischange happened in some parts of the river, such as Wuding river, Yu river, Kuye river andTuwei river etc, where people reclamationbottomland used to arable land at the riverside andbuilt silt arrester in the eastern and southeast loess gully and hilly areas in order toconversationsoil erosion. The large scale of dry land became to saline-land bring about the increasing of its areas,sharply. In particularly , during the beginning to middle of monitor, the velocity of rising was3267.9hm2 per year and the area extended 19607.1hm2 for 6 years. Through landscape patternanalysis found out that it's patches were enhanced with fragmentation process, especially inDingbian and Jingbian county. iii Sandy desertification is one of major kind of land use /land cover in the study area.According our research and practice on land degradation in the zone, we defined the sandydesertification situation was more serious and the area of desertification has exceeded 1/3 oftotal land area of the region, which the spatial extent o...