Effect of Shrub on the Alpine Meadow Soil Ecosystem in the Northwestern Plateau of Sichuan Province,China

The northwestern plateau of Sichuan province is the important zone of containing water of Yangtze River and the Yellow River,and the important part of South agriculture and stock breeding interlaced area,the ecosystem is very frangibility because of high altitude and cold climate.Latter years,the grassland degradation and desertification is very serious.The course of land degradation is the transformation at time and space distributing of soil resource.This article studied the relations between the vegetation change and space distributing of soil resource.This research used pane sampling,random sampled 50 soil samples in the depth of 0～20 cm of each site in two adjacent sites representing the Alpine meadow and Alpine shrubland respectively,in study area in Hongyuan county of the northwestern plateau of Sichuan province,and analyzed the nutrition composition of these soil samples.Have been done statistical work,analyzed and compared these experimental data using the SPSS(11.0),studied the mean concentration,spacial heterogeneity and correlation relation of each soil nutrient.Results indicatedthat meadow is higher than shrub land in concentration of soil viscid grain,P_(total),N_(total),ORG,P_(avail),N_(avail),K_(avail),and difference is the best significant of the quick nutrients.But it is notable that meadow soil is significant lower than shrub land at the coefficient of variation(CV) of ORG,N_(avail),K_(avail)in soil samples,especially CV exceeding(53.37 %) were found for K_(avail)in the Alpine shrub land than Alpine meadow.The correlation analyse showed that the correlation of shrub land is not able stronger,relativing to the meadow.Showed that shrub have significant impact to the resource heterogeneity of Alpine meadow soil ecosystem,it exists to decrease the meadow soil nutrient' average concentration and increase it's variability,these didn't go against the soil nutrient' holding in the Alpine meadow.