|其他摘要||Irtysh River takes its rise among the Altai Mountains, and is the only river of the arctic ocean water system in China. The location of Irtysh River is a temperate arid district, with less heat, cool weather, less rainfall in plains, abundant precipitation in mountainous areas, which helps to form a rich community of vegetation types including tree, shrub, grass and its mixed floras. But the shrub vegetation distribution is sparse,and mainly includes White silk stem pole, hin silk pole, bells and other desert thorn bushes.In this study, typical shrub vegetation in Irtysh River was investigated. based on the classification of shrub communities and by using the variability andquantity sorting theory of soil, the major environmental factors which affect shrub community diversity and distribution patterns were analyzed. The results expounds the basic spatial distribution pattern of the soil properties of the Shrub communities and its main environmental factors of the Irtysh River basin in xinjiang, which will Provide a scientific basis for the study of Land use type and vegetation succession of this area.
1)The semi variance function analysis of the soil water content shows that the soil water content of 0-20cm is in line with the Gauss model, 20-40cm is in accordance with the spHerical model, and 40-60cm is in line with the linear model. Spatial interpolation of soil water content reflects that the high water content area is located at the mountain area of Kanas with the elevation of 1200-2100m. The lower water content area is in the middle part of Irtysh River among the Plain Desert area.
2)Semi variance analysis of soil nutrient shows that soil available carbon, organic matter and total nitrogen is in line with the Gauss model, available potassium is in accordance with the linear model, the effective nitrogen is in accordance with the spHerical model. The high content area of organic matter, soil total nitrogen, available nitrogen, available pHospHorus, available potassium is in the high mountain area of Kanas, the low content area is in the middle part of Irtysh River among the Plain Desert area.
3)The semi variance function analysis of soil salinity showed that the total salt, Mg2+, Ca2+ and Cl- are in line with the linear model, K+ and HCO3- are in accord with the Gauss
model, and SO42- and Na+ are in accordance with the spHerical model. The regional distribution of soil total salt and the ion content is essentially the same: the high distribution area is among the valley plain where the two rivers meet, and the middle part of Irtysh River among the Plain Desert area. The low distribution area is among the medium high mountain area of Kanas and Keketuohai.
4)There are mainly nine shrub communities among the Irtysh river basin, The longitudinal variation of soil nutrition element of the nine shrub communities are: soil organic matter increases with the increase of soil depth generally and difference between different communities is significant. Soil total potassium and available potassium showed the opposite change in the vertical distribution, which decreases with the increase of soil depth. soil available potassium increases with the increase of soil depth, but the difference between different communities is not significant. Soil total pHospHorus and available pHospHorus increase with the increase of soil depth. the soil salt content differs significantly between different communities and different area.
5)Detrended Canonical Correspondence Analysis（DCCA）analysis showed eigenvalues of the first two ordination axes were 0.96,0.79.contribution of the first is axe 15.9%, cumulative contribution rate of the second axe is 12.6%.The first ax reflects the gradient variance of total salt and total potassium of different shrub communities and soil environment, among which total salt is the most important changing gradient.The second axis substantially exhibits the variation tendency of soil moisture content and elevation of different vegetation communities. Thus, changes in the total salt content and soil water content are the abiotic environmental factors that determine the distribution of the shrub vegetation among Irtysh River Basin.|