| After long-term human disturbance and destruction,the vegetation in the lake basin has led to insufficient surface vegetation cover in mountainous and mountainous areas.Additionally,the understory vegetation of heterogeneous forest land and economic forest restored in different periods in the later period is sparse,resulting in a low degree of depression,,poor ecological functions such as water storage and soil retention capacity,and a relatively single and unreasonable community structure.In this study,the diversity index,important values,soil physicochemical properties,soil organic carbon and soil organic carbon content and proportion of different components(soluble organic carbon(DOC),light organic carbon(LPOC),oxidizable organic carbon(ROC),and different components of soil organic carbon(soluble organic carbon(DOC),light organic carbon(LPOC),oxidizable organic carbon(ROC),were measured in different lake basins.The distribution characteristics of particulate organic carbon(POC),mineralizable organic carbon(MOC)and soil water stable aggregates were analyzed,and the composition of plant communities and their species diversity in different vegetation types were analyzed.The size and distribution characteristics of soil carbon pool under different plant community types were understood,and the quality and stability of organic carbon and its components in soil in different plant communities were evaluated.The fixation role of soil organic carbon in different plant communities and its involved mechanisms were preliminarily explored.The main results are as follows:(1)The community structure and diversity characteristics of different plants in the barren slope shrubland(YN),fallow forest(YS),and artificial restoration forest(DS)are different,and the species richness of the shrub layer barren slope shrubland is significantly higher than that of fallow forest and artificial restoration forest.The species diversity index showed the rule of herb layer>shrub layer>tree layer in different plant community.(2)The content of soil organic carbon and its components decreased with the increase of soil depth,and had obvious "aggregation" characteristics.The soil organic carbon content of the 0-20 cm layer was significantly higher than that in the 40-60 cm soil layer.The distribution of total soil organic carbon and organic carbon density in the soils of the three vegetation types was generally as follows: barren slope shrubland>fallow forest > artificial restoration forest.(3)The organic carbon component content of the soil in the three vegetation types was generally manifested as follows: barren slope shrubland> fallow forest > artificial restoration forest.Among them,the organic carbon content of soil particulate matter accounted for a large proportion of soil organic carbon content.(4)The differences in the distribution of soil hydrostable aggregates were mainly concentrated in >5mm and 2-5mm,and the differences in other particle size levels were not obvious,and the MWD artificial secondary forest of soil hydrostable aggregates in each layer was larger than that of fallow forest,and the barren slope shrub and grassland were the smallest.The average weight of soil aggregates is 0-20 cm in diameter,and the soil layer is higher than that of other soil layers,and decreases sequentially as the soil layer deepens.(5)The correlation between total soil organic carbon and its activated carbon components reached a very significant positive correlation.There was a significant positive correlation between soil organic carbon and total nutrients,negatively correlated with soil physical properties,and LPOC was negatively correlated with H Shannon Wiener index.Different plant communities had significant effects on SOC,LPOC,MOC,ROC,POC,DOC/SOC.The depth of soil layer has a significant effect on SOC,DOC,LPOC,MOC,ROC,POC,ROC/SOC.The interaction between plant community and soil depth had a significant effect on LPOC and POC/MOC.BD,TP,CPO,TN,H,TPO,Ph,TK all affected SOC and its components,and together they explained 49.1% of the variation. |
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