广西雅长人工林与天然林土壤养分和微生物群落多样性对比研究OA

[Objective]This study aims to explore soil microbial diversity in artificial ecological pubic welfare forests of Pinus massoniana and Eucalyptus urophylla by comparing them with zonal natural public welfare forests.[Method]Soil bacterial and fungal communities were investigated in 2 artificial public welfare forests,and 2 natural pubic welfare forests(karst,and non-karst natural forests)in Yachang Orchid Natural Reserve,Guangxi.The influence mechanism of plant communities and soil factors on the composition and diversity of soil microbial communities across different forest types were analyzed.[Result]The contents of total carbon,total nitrogen,total phosphorus,available potassium,and available calcium in the soil of artificial forests were significantly lower than those in zonal natural forests(P＜0.05),while there was no significant difference in available magnesium.The available phosphorus in artificial forests was significantly lower than that in non-karst natural forests and higher than that in karst forests(P＜0.05).The Shannon-Wiener,Simpson,and evenness indices of bacteria in P.massoniana forests were significantly higher than those in karst forests(P＜0.05),but there was no significant difference in non-karst natural forests.There was no significant difference in species richness index between P.massoniana forests and zonal natural forests.The species richness,Shannon-Wiener,Simpson,and evenness indices of bacteria in E.urophylla forests were not significantly different from those in zonal natural forests.The species richness index of fungi in artificial forests was significantly lower than that in zonal natural forests(P＜0.05),while no significant differences were found in the Shannon-Wiener,Simpson,and evenness indices.There were significant differences in the composition of bacterial and fungal communities among different forest types(P＜0.001),and the main influencing factors were plant community composition(explaining 33.4%and 21.2%of the variation,respectively)and soil total nitrogen content(explaining 24.8%and 7.8%of the variation,respectively).The difference in bacterial community composition was also influenced by soil pH(explaining 20.9%of the variation),while the fungal community composition was influenced by soil temperature(explaining 7.2%of the variation).This resulted in a significant decline in the relative abundance of nitrogen-fixing bacteria(such as Xanthobacteraceae)and copiotrophic and alkaliphilic bacteria(such as Proteobacteria,Actinobacteria and Bacteroidetes)in artificial forests,while the relative abundance of oligotrophic and acidophilic bacteria(such as Acidobacteria and Chloroflexi)increased.There was a significant increase in pine-associated symbiotic fungi(such as Mortierellaceae and Sebacinaceae)in P.massoniana forests,and eucalyptus-associated symbiotic fungi(such as Gloniaceae)in E.urophylla forests.In contrast,the symbiotic fungi(such as Russulaceae)of oak trees(the dominant species in natural forests)and copiotrophic,cold-adapted fungi(such as Hymenogastraceae)decreased in both artificial forests.There was no significant difference in bacterial functional groups among different forest types,while there were significant differences in fungal functional groups.[Conclusion]The artificial public welfare forests of P.massoniana and E.urophylla still face the problems of a monotonous plant community and declining soil nutrients,resulting in a significant reduction in fungal diversity and significant changes in functional groups,but bacterial diversity and functional groups have not been significantly affected.