Afforestation is thought to be one of the key measures for mitigating climate change by capturing atmospheric carbon. However, despite the importance of afforestation in ecosystem functioning, its effects on soil microbial diversity and enzyme activity remain unclear. In this study, we conducted a meta-analysis of these effects, using a newly compiled dataset of soil microbial diversity and enzyme activity before and after afforestation collected from 80 sites worldwide. Soil fungal diversity and soil enzyme activities increased significantly after afforestation, but soil bacterial diversity did not change significantly. Among these soil enzymes, the activities of β-1,4-glucosidase (BG), urease (UREA), alkaline phosphatase (AP), dehydrogenase (DEH), and catalase (CAT) increased by 104.7%, 84.0%, 101.7%, 199.2%, and 58.3%, respectively. The responses of soil microbial diversity and enzyme activities varied across afforestation durations, climate zones, prior land use types, and species. Specifically, soil bacterial diversity and the activity of BG increased significantly with afforestation duration, and the increase in BG activity was higher in tropical than in temperate zones. In degraded sites, both soil microbial diversity and enzyme activities significantly increased after afforestation. In addition, structural equation models showed that soil carbon content, nitrogen content, and soil pH value were significant driving factors for the soil microbial community diversity and soil enzyme activities. Overall, our results provided a comprehensive understanding of the changes in soil microbial diversity and enzyme activity under different afforestation conditions, as well as scientific bases for locally adapted afforestation in the future.

植树造林被认为是通过捕获大气碳来缓解气候变化的关键措施之一。然而，尽管植树造林在生态系统功能中很重要，但其对土壤微生物多样性和酶活性的影响仍不清楚。在这项研究中，我们使用从全球 80 个地点收集的造林前后土壤微生物多样性和酶活性的新汇编数据集，对这些影响进行了荟萃分析。造林后土壤真菌多样性和土壤酶活性显着增加，但土壤细菌多样性没有显着变化。在这些土壤酶中，β-1,4-葡萄糖苷酶（BG）、脲酶（UREA）、碱性磷酸酶（AP）、脱氢酶（DEH）和过氧化氢酶（CAT）的活性分别提高了104.7%、84.0%、101.7% 、199.2% 和 58.3%。土壤微生物多样性和酶活性的反应因造林持续时间、气候带、先前的土地利用类型和物种而异。具体而言，土壤细菌多样性和BG活性随着造林时间的延长而显着增加，并且热带地区BG活性的增加高于温带地区。在退化场地，植树造林后土壤微生物多样性和酶活性均显着增加。此外，结构方程模型表明，土壤碳含量、氮含量和土壤pH值是土壤微生物群落多样性和土壤酶活性的重要驱动因素。总体而言，我们的研究结果全面了解了不同造​​林条件下土壤微生物多样性和酶活性的变化，