Study On Soil Physical Properties And Ecological Suitability Classification In Red Soil Hilly Area

The red soil hilly area is a natural environment type that ecological stability is bad, the biologic configuration and productivity change acute, act intensively response to human activity and paroxysmal disaster, natural environment change easily against to human using. The red soil upland distributes very abroad in our southeast country, include l1 provinces and 619 county, the area is 1,130,000 kilometers in all, accounting for 11% of national territory area. This region have superior biologic and climate condition, the average year temperature is 16-19℃, the rainfall of a year is 1400-1700 mm, the potential of product is very bigly, but because people make use of resource overly for long time , At present, the region's soil erosion is serious, the productivity of land descent .The disaster of drought and water turn worse, the ecosystem stability reduces, the natural environment is becoming as one of the weak regions in ecosystem environment in our country. The environmental flimsiness in ecosystem has affected seriously to the product and people's life of this area. As a result, analyze above-mentioned status, studying the region's soil physical property, make sure the appropriate ecological classification, know the soil status from the macroscopically side and microcosmic side. This research has important academic and practical significance.About macroscopic aspect, under the support of the geography information system, this paper analyzes the factors, which will influence the ecological process, of which the physiognomy factor on the ecological suitability classification is mainly discussed. As a result, the percentage of the highly suitable land, suitable land, moderately suitable land, not suitable land and permanently not suitable land respectively is 1.95% , 8.12% , 23.96% , 42.72% and 23.25%,the result consist with the city construction. The result of this research indicated that the approach integrating with physiognomy factor as an important index is very necessary for the ecological suitability classification, and the result is more reasonably and more suitable with the local physical and social status than other methods.In the microcosmic aspect, the observation proving ground of agriculture institute in taoyuan belong to Chinese Academy of Sciences is the experiment area, which is the typical representation of red soil mound area, the soil physical characters such as the saturated soil hydraulic conductivity, aggregate of soil and grain compsing of ecosystems in the proving ground were synthesizing analysed. The Research result show that: the saturated soil hydraulic conductivity and configuration of soil aggregate in the artificial, nature and farmland three greatest ecosystems were obviously changed in space and time. Three regulations exsit as below: first, in each small area the saturated soil hydraulic conductivity of down slope is obviously higher than it of up slope; the configuration of soil aggregate of down slope is also better than up slope. Second, the surface layer soil saturated hydraulic conductivity of the 0-20cms is higher than it of the 20-40cms; the average weight diameter (MWD) of the 0-20cms is also higher than it of the 20-40 cms. Third, the difference of grain compsing between all ecosystems is not very big, the quality type is similar with the soil of clunch, and it also has the general characteristics of the red soil. The result of research show that: the soil physical characters such as the saturated soil hydraulic conductivity, aggregate of soil and grain compsing exsits difference because of the difference of ecosystem system,position of slope and soil layer depth. In the ecosystem recover process, saturated soil hydraulic conductivity and the configuration of soil aggregate were improved with different degree, but the change of soil quality was very slow.