Spatial Variation Of Community Characteristics And Soil Nutrient In Family Ranch Scale

The spatial distribution, interrelationship of vegetation and soil properties and altitude in the household pastures scale were analyzed in this experiment, which was based on the vegetation map, soil map, geomorphologic map and field survey for creating DEM and extracting terrain factors and overlaying. The statuses of vegetation and soil fertility in the household pastures on the different elevation were investigated. The three-dimension visualization model of vegetation and soil spatial distribution were created, which displayed the relationship between vegetation and soil type distribution and environment directly, and could help to understand how the spatial distribution of vegetation and soil and its proper-ties changed with the terrain. The main results were shown as follows:1. The ranch showed out different types of grassland in the family ranch with the change of elevation. They were the high plains grasslands in the range of 1423~1470m elevation, the lower wetland grassland in the range of 1327～1342m elevation, the sandy grassland and lower wetland grassland in the range of 1343～1358m elevation, and the sandy grassland in the range of 1359～1390m elevation.2. Perennial grasses was dominant in the whole pasture. The heights, coverage and densities of annual grasses, such as Chenopodiaceae, Salsola collina Pall and Chenopodium acuminatum Willd were relatively large, and important values of perennial grasses and forbs were high.3. The aboveground present biomass were high in the lower wetland grassland of lowest elevation, in turn, in the zone sandy grassland and lower wetland grassland, of which in the high plains grassland of the highest elevation were low.4. The contents of crude protein and crude fat of forages decreased with the decrease of elevation. The crude fiber content of forages increased with the increase of elevation. The contents of calcium and phosphorus of forages were high within middle-elevation.5. The contents of sand grain and the clay in the soil mechanical composition were high in the high plains grassland of the high elevation.6. The contents of soil total nitrogen, available nitrogen, available kalium and organic matter were high in the sandy grassland and lower wetland grassland. The contents of soil total phosphorus, available phosphorus and total kalium content were high in the lower wetland grassland of lowest elevation and the sandy grassland.