Soil carbon (C) plays a critical role in the global C cycle and has a profound effect on climate change. To obtain an in-depth and comprehensive understanding of global soil C changes and better manage soil C, all meta-analysis results published during 2001–2019 relative to soil C were collected and synthesized. The effects of 33 influencing factors on soil C were analyzed, compared and classified into 5 grades according to their effects on soil C. The effects of different categories of influencing factors, including land use change (LUC), management and climate change, on soil C and the underlying mechanism were compared and discussed. We propose that natural ecosystems have the capacity to buffer soil C changes and that increasing C inputs is one of the best measures to sequester C. Furthermore, a comparison between the meta-analyses and previous studies related to soil C based on bibliometric analysis suggested that studies on wetland soil C, soil C budgets and the effects of pollution and pesticides on soil C should be strengthened in future research.

中文翻译：

---

土壤碳的变化：影响因素，固存策略和研究方向。

土壤碳（C）在全球碳循环中起着至关重要的作用，并且对气候变化具有深远的影响。为了深入，全面地了解全球土壤碳的变化并更好地管理土壤碳，收集并综合了2001-2019年间发表的有关土壤碳的所有荟萃分析结果。根据33种影响因素对土壤C的影响进行了分析，比较和分类，分为5个等级。不同类别的影响因素，包括土地利用变化（LUC），管理和气候变化对土壤的影响对C及其潜在机制进行了比较和讨论。我们建议自然生态系统具有缓冲土壤碳变化的能力，并且增加碳输入是隔离碳的最佳措施之一。此外，