Distribution Characteristics Of Soil Organic Carbon Content And Soil Respiration In Daihai Lakeside Zone

As the largest carbon pool and an important part of carbon cycle,soil organic carbon plays a key role in climate change and greenhouse gas emissions.Lake shrinkage can affect carbon cycle patterns to a certain extent.In this paper,soil organic carbon in the coastal zone of Daihai Lake,a typical inland lake in arid and semi-arid regions,was studied by measuring and analyzing soil organic carbon content in different habitats,vegetation growth periods and soil respiration in each month of growth season.The main research results are as follows:（1）Soil organic carbon content in different habitats of Daihai Lakeside zone from high to low is N-SG,N-BL,N-LS,S-PC,S-BL,S-LS.In vertical distribution,the total soil organic carbon content in Suaeda glauca community,Phragmites communis community and bare land increased first and then decreased with the deepening of soil layer,while the total soil organic carbon content in Leymus secalinus community decreased first,then increased and then decreased.（2）Correlation analysis showed that TOC was significantly correlated with DOC,EOC and POC.Soil total nitrogen、soil p H and soil water content were the main influencing factors.The structural equation model showed that soil water content was the main factor affecting soil organic carbon and its components,followed by soil p H and soil conductivity,and soil environmental factors indirectly affected soil organic carbon and its components through total nitrogen.（3）Soil respiration showed a single peak curve pattern in different habitats in the Daihai Lakeside zone during the growing season,and reached its maximum value in July,which was consistent with temperature and precipitation.（4）There was a certain correlation between soil respiration and organic carbon and its components,as well as environmental factors such as p H and water content,but none of them was significant.In addition,environmental temperature,precipitation and groundwater level all had a certain influence on soil respiration.The structural equation model showed that soil water content was the main driving factor affecting soil respiration in Daihai lakeside wetland.The results of this paper can provide theoretical basis and data support for the carbon sink assessment of lake and lakeside wetland ecosystems in arid and semi-arid regions and the restoration and reconstruction of lake and lakeside wetland ecosystems in degraded lakes.