祁连山南麓不同植被类型土壤生态化学计量特征与碳储量OA

[Objective]This study aims to investigate the differences in soil nutrients and soil organic carbon storage(SOCS)under different vegetation types on the southern foothills of the Qilian Mountains,and to reveal the mechanisms by which soil ecological stoichiometric characteristics affect SOCS.This work provides a scientific basis for regional vegetation restoration and carbon sink function assessment.[Methods]Shrublands,Betula platyphylla broadleaf forests,Betula platyphylla-Picea crassifolia mixed coniferous-broadleaf forests,and Picea-crassifolia coniferous forests on the southern foothills of the Qilian Mountains were selected as study objects.The relationships of soil organic carbon(C),total nitrogen(N),total phosphorus(P),and their stoichiometric ratios with SOCS were examined.[Results]Soil C,N,and P contents differed significantly(p<0.05)among different vegetation types on the southern foothills of the Qilian Mountains,with the mixed forest exhibiting the highest soil C and N contents,and shrublands showing the highest soil P content.Soil C/N did not differ significantly(p>0.05)among vegetation types,whereas soil C/P and N/P were strongly affected by vegetation type,following the order:Betula platyphylla broadleaf forest>mixed coniferous-broadleaf forest>shrubland>Picea crassifolia coniferous forest.SOCS also differed significantly among vegetation types(p<0.05)and decreased in the order:mixed coniferous-broadleaf forest>Betula platyphylla broadleaf forest>shrubland>Picea crassifolia coniferous forest.Microbial diversity responded differently to vegetation types.Shrublands exhibited the highest bacterial diversity,Betula platyphylla forests favored fungal diversity,while Picea crassifolia forests had the lowest overall microbial diversity.The dominant factors controlling SOCS varied among vegetation types.In shrublands,aboveground plant litter(PL)was the key factor regulating SOCS variations,whereas in Betula platyphylla broadleaf forests,mixed coniferous-broadleaf forests,and Picea crassifolia coniferous forests,SOCS was primarily regulated by N content and the N/P ratio.[Conclusion]Different vegetation types on the southern foothills of the Qilian Mountains significantly affect the soil organic carbon sequestration process by altering soil nutrient status and the C/N/P balance pattern.SOCS depends not only on carbon input but also on stoichiometric regulation.This study provides theoretical support for assessing carbon sink potential and optimizing nutrient management during vegetation restoration in this region.