杉木纯林和复层异龄混交林土壤多功能性比较研究OA

[Objective]This study aimed to investigate changes in soil multifunctionality and to identify its key driving factors following the conversion of monoculture Chinese fir(Cunninghamia lanceolata)planta-tions into mixed,uneven-aged,two-layered plantations composed of Chinese fir and Phoebe chekiangen-sis(hereinafter referred to as two-layered plantations).The objective was to provide a scientific basis for evaluating the ecological benefits of close-to-nature plantation management.[Methods]Based on Chinese fir monocultures and two-layered plantations,changes in topsoil(0～20 cm)properties of the two stand types,including soil nutrients,enzyme activities related to carbon(C),nitrogen(N),and phosphorus(P)cycling,soil fungal diversity,community composition,and function,as well as multifunctionality indices re-lated to C,N,and P cycling were analyzed.Variance partitioning analysis was applied to quantify the relat-ive contributions of fungal communities and vegetation factors to soil multifunctionality.[Results]Com-pared with monocultures,the contents of soil organic carbon,total N,total P,and available nutrient con-tents in two-layered plantations increased by 17.6%～91.1%.The activity of β-1,4-glucosidase significantly increased,whereas the activities of β-1,4-N-acetylglucosaminidase and acid phosphatase significantly de-creased.The soil fungal α-diversity and the relative abundances of Basidiomycota,Rozellomycota,Mortier-ellomycota and Mucoromycota in two-layered plantations increased significantly compared with monocul-tured plantations.In addition,the relative abundances of saprotrophic,saprotrophic-symbiotic,pathogen-ic-symbiotic,and pathogenic-saprotrophic-symbiotic fungi were also significantly higher in two-layered plantations.The functional indices of soil C,N,and P cycling and overall multifunctionality in two-layered plantations were 5.4,1.7,1.8,and 2.3 times higher than those in monocultures plantations,respectively.Soil fungal communities(α-diversity,composition,and function)and vegetation factors(litter and fine root biomass)explained 92.3%of the variation in soil multifunctionality,with fungal communities contributing a larger proportion than vegetation factors.[Conclusion]The conversion of monoculture Chinese fir planta-tions into two-layered plantations can significantly improve soil multifunctionality,particularly carbon cyc-ling functions.These improvements are primarily derived by shifts in soil multifunctionality diversity,com-position,and fungal structure.These findings deepen the understanding of how forest structure regulation maintains soil fertility and provide theoretical support for the close-to-nature transformation of subtropical plantations.