川西亚高山森林转换对土壤腐殖质碳积累的影响OA

[Objective]Humus carbon(HC)is a crucial component of the stable carbon pool in forest soils.Studying its accumulation characteristics is of great significance for improving forest management and contributing to carbon neutrality.[Method]Using natural and planted forests of Picea asperata in western Sichuan as study subjects,we employed 13C stable isotope tracing technique through in-situ field incubation experiments to investigate the changes and influencing factors of soil humus carbon accumula-tion at different soil layers under the treatment of adding litter(leaves and roots).[Result]Soil humus carbon content was significantly higher in the natural forest(27.4±3.2)g/kg than in the planted forests(22.7±1.4)g/kg.After 150 days of adding litter for incubation,the content of soil humus carbon in differ-ent soil layers showed a downward trend,while the addition of exogenous litter to some extent slowed down the decline of humus carbon.The proportion of litter-derived soil humus carbon in the total soil hu-mus carbon of the natural and planted forests of P.asperata trees ranged from 0.5%to 0.8%and 0.5%to 1.3%,respectively.It was more likely to accumulate in the 0-10 cm soil layer of the planted forest and the 10-20 cm soil layer of the natural forest.Root litter carbon contributed significantly more to soil hu-mus carbon than leaf litter in both forest types.Furthermore,path analysis revealed that the accumulation of litter-derived soil humus carbon in natural forests was influenced by the combined effects of soil physi-cochemical properties as well as microbial characteristics,while the paths for planted forests were rela-tively simple,mainly depending on soil physicochemical properties.[Conclusion]The conversion from natural to planted forests of P.asperata in western Sichuan has significantly altered the accumulation characteristics of soil humus carbon.These findings provide a scientific basis for enhancing soil carbon pool storage and stability in subalpine forest ecosystems.