The Study Of Soil Quality Properties Of Slope In Western Middle-Low Mountains Of Sichuan Basin

Many middle-low mountains in Sichuan have appeared plant landscape fragmentation, ecosystem diversification, and land use clot under human disturbance. This essay takes middle-low mountains in the western edge of Sichuan basin as the research area, and selects three typical mountains and two soil types according to the practical geomorphic features. Soil sampling is carried on on the typical slopes, and the mountain slope location that is being researched is divided into three parts: upper slope, middle slope, lower slope, and three land use ways are selected respectively in each slope location(altitude, slope gradient and aspect are same on the whole): farm land,, reforested land, waste land are taken as sampling sites.On the basis of the analysis of physicochemical properties of soil, analyzes variance characters of soil physical properties and nutrient properties in different land use ways and slope locations in the western edge mountains of Sichuan basin, and the results indicate that, in the respect of soil physical properties, it is either the soil structure coefficient or the degree of aggregation that is contained in farm land is obviously less than that is contained in reforested land and waste land, and because of the effects that forest crop root system and forest floor take, the soil physical properties of forest plantation is far better. Degree of aggregation of soil increases and constitutive property gradually enhances from upper slope to lower slope; of various types of utilizing on the same slope, the distribution of soil nutrients appears different variance characters, and the content of organic matter, total nitrogen, and alkali-hydrolysable nitrogen of reforested land is highest, which distinguishing from other types; the content of total phosphorus, total potassium, rapidly available phosphorus and rapidly available potassium of farm land is highest, which is not distinguished from two other types of utilizing. Because of a relatively good deal of rainfall in the research area, long dated scouring action causes many superficial nutrients to accumulate toward the foot of slope. The research of the effects that different landform parts take on the soil nutrients shows that, it is the lower slope that sloping nutrients accumulate, where the content of soil nutrients is higher than that of middle slope and upper slope, but because many nutrient elements differ greatly among teams under different slope location conditions, the discrepancy among teams is not notable. Cluster analysis suggest that soil nutrients are somewhat similar in different slope locations, so it is likely that the variation of soil chemical properties more depends on the way of land use.The analysis of the gradient characters of chemical properties of profile soil shows that, most of the content of nutrients represents characteristics of regular distribution, declining as the profile depth increases. However, the content of pH and total potassium increases as the profile depth increases. Variance analysis of the chemical indexes of profile suggests that organic matter, total nitrogen, alkali-hydrolysable nitrogen, rapidly available potassium and CEC are greatly different among layers of soil profile.The research of the composite index number (pi) of soil quality in different soillocations suggests that, the soil quality index increases as the altitude of mountain slope location decreases. Compared with that of upper slope, the soil quality of middle slope and lower slope improves, contrarily, the soil quality of upper slope can be considered to have the tendency to degenerate. The research of the composite index number (Qi) of soil quality in different utilizing ways suggests that, Qi of forest plantation is obviously higher, whereas qi of sloping cultivated land is the lowest. In mountain ecosystem, with the optimization of the ecosystem, that is, the mountain ecotype gradually successes from sloping cultivated land to types of landscape such as forest plantation etc., the soil quality improves.The distribution configuration of middle-low mountain soil quality mainly depends on the variations between land use and cover, and human activities is the main factor that enhances the variations. The degeneration of mountain ecosystem is the combined action of the frangibility and instability of ecosystem itself and the exterior jamming. So if the stable positive circle of mountain ecosystem and the sustainable development of soil quality are to be realized, a series of measures to improve soil quality and recover ecotope, such as reinforcing the treatment of farm land on the slope, enhancing constructions of the projects of vegetation conservation and protection.