Organic Carbon Compositions And Mineralized Characteristics Of The Oasis At The Northern Margin Of The Tarim Basin

Soil organic carbon is the largest carbon reservoir in terrestrial ecosystems and plays an important role in the carbon cycle of the earth.There are differences in soil organic carbon content and mineralization under different land use patterns.Studying them in-depth helps to further understand organic carbon.Cycle mechanism.Taking the oasis on the northern margin of the Tarim Basin as the target area,this study selected the wasteland,saline-alkali land,saline-alkali land,natural forest,artificial forest,sandy land,orchard,10a cotton field and 30a cotton field soil as the research object to determine MBC,DOC,and land use patterns.EOC and soil physicochemical factors were determined for different land-use types of organic carbon mineralization by indoor constant temperature culture and different methods of foreign aid addition.K-S,LSD,and RDA were used to conduct normality tests,multiple comparisons,and their correlations with environmental factors,respectively.Organic carbon mineralization was simulated and analyzed using first-order kinetic equations.The main conclusions are as follows:1.SOC,MBC,all show the highest values in natural forests,humus is the main concentration medium for organic carbon in land use patterns in arid areas;in addition,the main living environment of microorganisms in the study area depends on Populus euphratica and other shrubs.Litter;humic acid,which stores mainly DOC,is also enriched in litter of Populus euphratica.The highest content of EOC in cotton field30a,and the lowest content of sandy soil in 30a,proved that soil organic carbon in cotton field that has been disturbed by humans for a long time was more active than undisturbed sand,which provided ideas for the development and utilization of apprentice.2.The importance of environmental factors on the content of each carbon component is:soil bulk density>water content>conductivity>soil nitrogen>pH,ie,bulk density and water content are the main factors affecting the organic carbon composition in arid regions.3.Different foreign aids have positive or negative stimulating effects on soil organic carbon mineralization in various land-use types,and the mineralization rates all decrease with time.Urea was positively stimulated in saline-alkali soil,natural forest,artificial forest,orchard and 10a cotton field,and accumulated the highest amount of mineralization in saline-alkali soil and natural forest.Negative stimulating effect was observed in wasteland,sandy land and 30a cotton field.Sheep manure was positively stimulated in saline-alkali soil,wild grassland,natural forest,sandy land,artificial forest,10a cotton field and 30a cotton field,and negatively stimulated in the orchard.Straw addition was positively stimulated under all eight land use patterns,and the accumulation of mineralization was highest in wasteland,sandy land,artificial forest,orchard,and 30a cotton field.That is to say,in the five land use ways,the addition of straw can promote the activity of soil microorganisms.Among the 5.8kinds of land use methods,the mineralization rates in the first 20 days of cultivation decreased rapidly,and they increased when they were cultured for 30 days,but the mineralization rates slowed afterwards.In the end,there is a certain mineralization rate.It can be seen that the 90 days of culture is not the final culture time.4.Among the 4.8 land use types,the mineralization rates in the first 20 days of cultivation decreased rapidly,and they increased at the 30th day of culture,but the mineralization rates slowed afterwards.In the end,there is a certain mineralization rate.It can be seen that the 90 days of culture is not the final culture time.Poor soil in the study area is mainly limited by soil moisture content and bulk density,and the content of different organic carbon components is low.Different exogenous additions can change the respiration rate of soil microorganisms,thereby regulating the release of CO₂ from the soil and affecting soil quality,thus providing a reference for the rational development and utilization of local land.