Research Of Decision-making System For Returning Farmland To Forest Or Grassland By RS And GIS Technology In Loess Hill And Gully Area

Water and soil loss and desertification of land are most projecting zoology problems in our country. Its also result in frequently flood and prick up sand blown by wind. Returning farmland to forest or grass land is a item of zoology project which can melioration entironment, prevent water and soil losing and farmland translate to sand. Carry out returning farmland to forest or grass land not only necessity choice of father water and soil loss and strengthen entironment construct, but also push agriculture structure adjust and accelerate transform of tradition agriculture produce mode. Even more, it can accelerate country two and three industry develop, quicken step of rich.loess hill and gully area is the most brittle entironment region in our country. Water and soil loss and farmland translate to sand very serious. at the same time it also the region which rural economics drop behind and farmer income lower. It is the typical intergrowth region of zoology beggary and economy poor. Sloping farmland area occupy great proportion in loess hill and gully area. Sloping field once be dig up, Intrinsic nature balance destroyed, slope surface energy and matter occur change. Mostly be represented as soil layer thickness attenuation, soil texture turn coarse, soil organism and nutrient unceasing reduce, rainwater seep quantity reduce, soil physical and chemic character worsen, surface water and soil movement translate to disaster aspect, result in soil and water loss.Returning farmland to forest or grass land namely step by step to stop cultivate of the farmland which easy work water and soil loss and ground translate to sand. At the same time plant tree and grass to get back vegetation. Embody three kind: One is steep sloping field which 25 degree upwards. Two is slow sloping field which between of 15 and 25 degree. Three is farmland which easy translate to sand. Study layout of returning farmland to forest and grass land sustain by RS and GIS is a new method in recent years. It still not form a well-rounded apply mode and still in explore phase. RS can supervise and track the ground vegetation status fore-and-aft project. GIS can set up a ground numerical value model to simulate ground shape, progress space analysis, exact make certain the place and area of the farmland which want to be returned to forest and grass land.This paper based on the content and goal of decision-making study and GIS technique/s fast and effective and timely analysis function, in the light of systematism, expansibility, universality and maneuverability establish DTM and DEM. Design region decision-making system of returning farmland to forest or grass land. In the sustain of this system make Anding region of Gansu province as a case to study decision-making system of returning farmland to forest or grass land in loess hill and gully area. Via analysis educe the area and spatial geographic distributing. The area is 20322ha which occupy 19.6% of sloping farmland. In...