Study On The Relationship Between The Distribution Of Stellera Chamaejasme And The Soil Properties Based On GIS

Qinghai Province is an important base for the development of animal husbandry in China with resourceful meadow.In recent years,overstocking has brought grassland shrinkage,production decline,environment deterioration,poison grass increase.Stellera chamaejasme is one of the most serious weeds in grasslands degradation on the QingHai-Tibetan Plateau.Making use of GIS technology to analyzing the relationship of Stellera distribution and soil properties and studying the main influencing factors of the distribution of Stellera are of great importance to prevent Stellera and balance ecosystem.In this paper,typical degraded alpine meadow in Qilian County is the study area,making use of classical statistics,geostatistics theory and GIS technology,the thesis gives a contrast analysis of difference,by analyzing spatial heterogeneity,Spatial distribution pattern of vegetation,soil moisture,nutrition and microbial diversity in Stellera occurrence area and Stellera non-occurrence area,and further analyzing the relationship of Stellera and soil properties.Mainly achieved the following results:(1)The community coverage in occurrence area equals to non-occurrence area,but Spatial variability in occurrence area is greater in non-occurrence area.With a high variability,the spatial distribution pattern of coverage of Stellera showed obviously patchy pattern and spread from the center to around which lead to community coverage has a large variation in the whole sample area.(2)There were a significant difference in TN,TP and OM between occurrence area and non-occurrence area,and the occurrence area is lower than non-occurrence area,and the degree of variation of occurrence area is higher than the occurrence area.The spatial distribution of TN,TP and OM in occurrence area showed obvious patchy patterns,while the spatial distribution of TP is more gently and is similar to distribution tendency of Stellera coverage.However,the correlation analysis shows that there was a significant negative correlation between TK and Stellera coverage and Stellera coverage increased with the decrease of TK.The spatial heterogeneity of TP has a significant effect on the spatial distribution of Stellera coverage.(3)There were significant differences in soil moisture content of 20-30 cm,80-90 cm and 90-100 cm layers.The mean of soil water content in 20-30 cm layer was significant higher in occurrence area,but the mean of soil water content in 80-100 cm layers were significant higher in non-occurrence area.The changes of soil water content of each layer have obvious regularity in occurrence area,shallow of soil showed obviously patchy pattern,deep of soil showed less patchy pattern,the spatial distribution of middle layer is relatively gentle.Soil water content in non-occurrence area showed stochastic changes.The correlation analysis showed that the soil moisture content of 0-100 cm decreased gradually with the increase of Stellera coverage.From the soil moisture content of the layers,soil moisture of 10-20 cm?70-100 cm layers is significantly negatively related to Stellera Coverage.But soil moisture of 30-50 cm level is significantly positively related to Stellera Coverage.The spatial distribution of soil moisture and the spatial distribution of Stellera Coverage are interdependent.(4)There were significant differences in soil microbial diversity between occurrence area and non-occurrence area,and the community richness and diversity of occurrence area were relatively lower,but the community dominance was relatively higher.The spatial distribution of the community richness and diversity have more obvious patchy pattern,and was similar to the spatial distribution trend of Stellera coverage.However,the correlation analysis showed that the relationship between soil microbial diversity index and Stellera coverage were insignificant.