Original data

In this study, we determined the soil properties, root traits, and microbial community as well as their correlations in two soil depths in <i>Populus tomentosa</i>,<i> Platycladus orientalis</i>, and <i>Sophora japonica</i> plantations with different forest ages. Our results showed that at the phylum level, the highest relative abundance of soil bacteria and fungi were Actinobacteriota (18.63-32.74%) and Ascomycota (62.48-91.91%), respectively. The Chao, Shannon, and Pielou_e index of fungi in soils increased with forest age, while Alpha diversity of bacteria showed different trends with forest age across species. Redundancy analysis and hierarchical segmentation analysis showed that the effect of soil properties and root traits on composition of soil bacteria (41.4%) was larger than fungi (28.8%). Compared with root traits (7-10 %), soil properties exhibited larger effects (23-26%) on the composition of microbial community. Soil clay, water content, and conductivity showed positive effects on bacterial diversity and composition, while fungi were mainly affected by soil total phosphorus and pH. The influence of root traits on bacterial diversity weakened while that of soil properties increased with forest age. The fungal diversity in middle-aged plantations was affected by soil and root, while that of younger- and older-aged were affected by soil properties. As soil depth increased, the impact of roots on bacterial diversity increased while the effect on fungal diversity decreased. The results highlight the need to consider forest age and soil depth when revealing the association among soil microbial diversity, environmental variation, and root traits.

本研究针对不同林龄的毛白杨（*Populus tomentosa*）、侧柏（*Platycladus orientalis*）和国槐（*Sophora japonica*）人工林，测定了两层土壤的土壤性质、根系性状与微生物群落（microbial community），并分析了三者间的相关性。研究结果显示，在门水平上，土壤细菌和真菌的最高相对丰度类群分别为放线菌门（Actinobacteriota）（18.63%~32.74%）和子囊菌门（Ascomycota）（62.48%~91.91%）。土壤真菌的Chao指数（Chao index）、香农指数（Shannon index）与Pielou均匀度指数（Pielou_e index）均随林龄增大而升高，而不同树种的土壤细菌α多样性（Alpha diversity）随林龄呈现出不同的变化趋势。冗余分析（Redundancy analysis）与分层分割分析（Hierarchical segmentation analysis）结果表明，土壤性质与根系性状对土壤细菌群落组成的解释度（41.4%）高于真菌群落（28.8%）。与根系性状（7%~10%）相比，土壤性质对微生物群落组成的解释度更高（23%~26%）。土壤黏粒含量、含水量与电导率对细菌多样性及群落组成具有正向影响，而真菌群落则主要受土壤全磷含量与pH值的调控。随着林龄增大，根系性状对细菌多样性的影响逐渐减弱，而土壤性质的解释作用则逐渐增强。中龄林的真菌多样性同时受土壤性质与根系性状的调控，而幼龄林与过熟林的真菌多样性仅受土壤性质影响。随着土壤深度增加，根系对细菌多样性的影响逐渐增强，而对真菌多样性的影响则逐渐减弱。本研究结果表明，在解析土壤微生物多样性、环境因子变异与根系性状间的关联时，需充分考虑林龄与土壤深度的影响。