| Soil organic carbon(SOC),as a huge carbon storage pool,is affected by temperature,water content,terrain,vegetation type,and human interference,and its content also shows certain changes.The Sejila Mountain forest,as an important soil carbon pool in the western plateau region,has a high content of soil organic carbon.The changes in vegetation types have a profound impact on the changes in forest material cycling processes,thereby generating feedback effects on vegetation.It can reflect small changes in soil caused by the environment before changes in the soil carbon pool,and is an important pathway for the extremely active organic matter component and vegetation soil material cycle in the terrestrial soil carbon pool.Therefore,clarifying the impact of vegetation type changes on the main functions of forest ecosystems is one of the hot topics in current research.This study focuses on the grasslands,shrubs,and forest soil near the sunny slope forest line of Sejila Mountain.They went to Sejila Mountain for field sampling in April 2021(early plant growth stage),July 2021(peak plant growth stage),and October 2021(late plant growth stage).The collected soil samples were brought back to the laboratory for air drying treatment,and the required data for the experiment was then determined.Use descriptive statistics and one-way ANOVA to conduct statistical analysis on the sampled data.A systematic study of the content and dynamic characteristics of soil organic carbon components and physicochemical properties in the high mountain forest line of Sejila Mountain is helpful in exploring the dynamic changes of soil organic carbon pool in the high mountain forest line of Sejila Mountain,in order to gain a deeper understanding of the accumulation patterns of soil organic carbon in different vegetation types of Sejila Mountain in Tibet,and provide reference for forest management and management in the region.The main conclusions obtained through research are as follows:(1)There is a correlation between soil organic carbon and physicochemical properties and vegetation types.In this study,the content of SOC(organic carbon),MBC(microbial biomass carbon),DOC(soluble organic carbon),EOC(easily oxidizable organic carbon),POC(particulate organic carbon),LFOC(light component organic carbon),and HFOC(heavy component organic carbon)in meadows was lower than that in shrubs and forests,The difference in organic carbon and its components between shrub and forest soil is not very significant.There are differences in AN(available nitrogen),AP(available phosphorus),AK(available potassium),TN(total nitrogen),TP(total phosphorus),TK(total potassium),soil bulk density,and soil p H among meadows,shrubs,and forests.However,some differences are not very significant.The AN,AK,TN,and content of shrubs and forests are higher than those of meadows.The AP,TP,TK,soil bulk density,and soil p H of meadows are slightly higher than those of shrubs and meadows,indicating that soil physicochemical properties are related to vegetation types.(2)There is also a correlation between soil organic carbon and physicochemical properties and soil layers.In this study,the soil organic carbon and its components in meadows and shrubs showed that the content of 0-10 cm soil layer was greater than that of 10-20 cm soil layer.The DOC content in forests showed that the content of 0-10 cm soil layer was smaller than that of 10-20 cm soil layer,while the other organic carbon components showed that the content of 0-10 cm soil layer was greater than that of 10-20 cm soil layer.Overall,soil organic carbon and its components showed surface aggregation,Mainly concentrated on the surface of the soil.The content of AN,AK,TN,and TP in meadows,shrubs,and forests is higher in the 0-10 cm soil layer than in the 10-20 cm soil layer.The values of soil p H and bulk density at 0-10 cm are also greater than those at 10-20 cm.(3)At different growth stages,there are differences in soil organic carbon and physicochemical properties.The variation patterns of soil organic carbon and its components in grasslands,shrubs,and forests vary at different growth stages,but their DOC content shows the same trend of change,reaching its maximum value at the end of growth and the minimum content at the beginning of growth.The soil physical and chemical properties of meadows,shrubs,and forests vary in the early,peak,and late stages of growth.The highest and lowest values of soil physical and chemical properties of the three vegetation types do not occur during the same growth period.(4)The SOC of grasslands,shrubs,and forests is significantly or extremely significantly positively correlated with EOC,POC,and HFOC,while MBC is significantly or extremely significantly positively correlated with POC and HFOC.EOC is significantly or extremely significantly positively correlated with POC,POC is significantly or extremely significantly positively correlated with LFOC,AN is significantly or extremely significantly positively correlated with AK and TN,and AK is significantly or extremely significantly positively correlated with TN.There is a significant or extremely significant negative correlation between TN in grasslands and shrubs and soil p H,and there are differences in the correlation between soil organic carbon components and physicochemical properties among different vegetation types.The EOC of grasslands,shrubs,and forests shows significant or extremely significant positive correlation with AN,AK,TN,while the correlation between other organic carbon components and physicochemical properties varies among different vegetation types.In meadow soil,there is a significant or extremely significant positive correlation between soil organic carbon and AP,TN,TP.The results indicate that various nutrients in the soil,especially nitrogen and phosphorus,are closely related to soil organic matter.The decomposition of litter on the soil surface will produce a large amount of organic matter,while also promoting the release of N and P. |
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