Characteristics Of Soil Nutrients And Ecological Stoichiometry At Different Altitude In The Mountains Of Southern Xinjiang

The spatial variability of soil nutrient content and ecological stoichiometry of mountain ecosystems at different scales and the factors influencing them are related to the elemental cycling processes and the response to environmental changes of mountain ecosystems,and therefore have received extensive attention from scholars.In recent years,studies on the mountains of southern Xinjiang have mostly focused on vegetation photosynthesis,community characteristics and plant diversity,while few studies have been reported on the relationships between their soil nutrient or ecological stoichiometric characteristics and environmental factors.Therefore,in this paper,by collecting soil samples from 1916-4335 m in the Kunlun Mountains and 1648-3584 m in the middle part of the Aerjin Mountains at different altitude gradients,we measured soil C,N and P contents at different depths,and calculated ecological stoichiometric ratios of C:N,C:P and N:P to explore the changes in soil nutrient and ecological stoichiometric characteristics with altitude gradients in the mountains of southern Xinjiang.Through analyzing the relationship between soil nutrient and ecological stoichiometric characteristic with soil total salinity,p H and vegetation factors(including community cover and height)as well as climatic factors such as mean annual temperature(AMT),mean daily difference in temperature(MDR),coefficient of seasonal variation in temperature(TS),maximum temperature in the hottest month(MAT),annual difference in temperature(TAR),mean temperature in the wettest quarter(MET)and precipitation in the driest quarter(PDQ),we explored the drivers of soil nutrients and ecological stoichiometry in the mountains of southern Xinjiang.The results will provide a basis for further understanding of soil C,N and P biochemical cycling in mountain ecosystems.The main results were as follows:(1)In the Aerjin mountains,only P content of soils in the 10-20 cm soil layer increased significantly with the increase of altitude,while the organic C,N and P content in the rest of the soil layers did not show any significant trend with the altitude increasing.In the Kunlun Mountains,only the soil organic C and P content of the 20-30 cm soil layer did not show a significant trend with increasing altitude,while the soil organic C,N and P content in the rest of soil layers showed a significant increase with increasing altitude.(2)Temperature and community cover were the main factors affecting the nutrient content of soils in the Aerjin and Kunlun Mountains.(3)C:N of 0-10 cm soil surface layer in the Aerjin and Kunlun Mountains was significantly influenced by temperature,while C:P and N:P of 0-50 cm soil layers were significantly influenced by temperature and community cover.