Soil Environmental Interpretation Of Community Distribution Of Desert Plant And Its Species Diversity In The Outer Space Of Karamay Agricultural Comprehensive Developmental Region

Desert ecosystem is the material and ecological base of artificial oasis in Xinjiang. Desert vegetation acting as the ecotone between desert and oasis plays an absorbable and alleviatory role in threatening of desertification in the outer space of Karamay Agricultural Comprehensive Developmental Region. It is also the composition of the protective system of shelter-ecological security in the region. This thesis focuses on the relation between soil factors and community distribution and species diversity by analysis of DCA ordination and regression on the basis of community ecology. Then the thesis provides theoretical and referential guidance for nursing and restoration of desert vegetation. The results as following:Through the DCA ordination analysis of plant community and cluster analysis of soil, desert plant communities can be divided into Halostachys caspica community, Haloxylon persicum community and Haloxylon ammodendron community according to constructive species. The results indicate that soil factors within the range of 0-35cm influents intensively the distribution of local community.Quantitative analysis of desert plant community and its habitat shows that the correlation between Halostachys caspica community and soil total salinity, Na⁺, Cl^- are obvious; the correlation between Haloxylon ammodendron community and the available N, the available P, the available K are apparent; the correlation between Haloxylon persicum community and PH value, CO₃^2-, HCO₃^-,organic matter are explicit. Furthermore, the boundaries between Halostachys caspica community and Haloxylon ammodendron community and Haloxylon persicum community are clear, but there is no bounder between Haloxylon ammodendron community and Haloxylon persicum community. What is more, there is a transition community between Haloxylon ammodendron community and Haloxylon persicum community. In this transition community from Haloxylon persicum community to Haloxylon ammodendron community, soil PH value is decreasing, the fertility is increasing, and vice versa.Analysis of community species diversity of desert plant suggests that diversity index based on important value is more reasonable than that of cover and richness. However, the change trend of three indexes is identical by and large. Moreover the correlation analysis about 10 kinds of species diversity indexes indicates that community species diversity in desert region is influenced mostly by evenness and abundance. And the relation between evenness and diversity is higher man the relation between abundance and diversity. In other words, species diversity rests principally with evenness in desert plant community.The research about species diversity of desert plant shows that diversity index is higher in co-dominant community. Analyzing the correlation between species diversity and soil factors by DCA ordination analysis, single variable regression and multivariate regression, the conclusions indicate that diversity index(H') and abundance(Ma) decreased as total salt, kinds of dissoluble salt in soil, fitting negative correlation; the relation between evenness and soil moisture can be expressed by cube regression equations; species diversities(D, H') and richness(Ma) increased as soil organic matter, nutrient content. The analysis indicates that abundance(Ma) depend mostly on C\ ,the whole N and the available N ; diversities index(D,H') are influenced mostly by Cl^-,the whole N, the available N and HCO^3- and evenness (Jsw)is affected only by soil moisture.