Grasslands occupy almost half of the world's land area. Soil organic carbon (SOC) is a key indicator of soil fertility and grassland productivity. Increasing SOC stocks (so-called SOC sequestration) improves soil fertility and contributes to climate change mitigation by binding atmospheric carbon dioxide (CO2). Grasslands constitute about 70% of all agricultural land, but their potential for SOC sequestration is largely unknown. This review paper quantitatively summarizes observation-based studies on the SOC sequestration potential of grasslands in six East African countries (Burundi, Ethiopia, Kenya, Rwanda, Tanzania and Uganda) and seeks to identify knowledge gaps related to SOC sequestration potential in the region. In the studies reviewed, SOC stocks in grasslands range from 3 to 93 Mg C/ha in the upper 0.3 m of the soil profile, while SOC sequestration rate ranges from 0.1 to 3.1 Mg C ha(-1) year(-1) under different management strategies. Grazing management is reported to have a considerable impact on SOC sequestration rates, and grassland regeneration and protection are recommended as options to stimulate SOC sequestration. However, a very limited number of relevant studies are available (n = 23) and there is a need for fundamental information on SOC sequestration potential in the region. The effectiveness of potential incentive mechanisms, such as payments for environmental services, to foster uptake of SOC-enhancing practices should also be assessed.

中文翻译：

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东非国家草原土壤有机碳封存潜力：综述

草原几乎占据了世界陆地面积的一半。土壤有机碳（SOC）是土壤肥力和草地生产力的关键指标。增加 SOC 储量（所谓的 SOC 封存）可提高土壤肥力，并通过结合大气二氧化碳 (CO2) 来缓解气候变化。草地约占所有农业用地的 70%，但它们对 SOC 封存的潜力在很大程度上是未知的。这篇综述论文定量总结了六个东非国家（布隆迪、埃塞俄比亚、肯尼亚、卢旺达、坦桑尼亚和乌干达）草原 SOC 封存潜力的基于观察的研究，并试图找出与该地区 SOC 封存潜力相关的知识差距。在审查的研究中，土壤剖面上部 0.3 m 的草地 SOC 储量范围为 3 至 93 Mg C/ha，而在不同的管理策略下，SOC 封存率为 0.1 到 3.1 Mg C ha(-1) year(-1)。据报道，放牧管理对 SOC 封存率有相当大的影响，建议将草地再生和保护作为刺激 SOC 封存的选项。然而，可用的相关研究数量非常有限（n = 23），并且需要有关该地区 SOC 封存潜力的基本信息。还应评估潜在激励机制的有效性，例如环境服务付款，以促进采用 SOC 增强实践。建议将草原再生和保护作为刺激 SOC 封存的选项。然而，可用的相关研究数量非常有限（n = 23），并且需要有关该地区 SOC 封存潜力的基本信息。还应评估潜在激励机制的有效性，例如环境服务付款，以促进采用 SOC 增强实践。建议将草原再生和保护作为刺激 SOC 封存的选项。然而，可用的相关研究数量非常有限（n = 23），并且需要有关该地区 SOC 封存潜力的基本信息。还应评估潜在激励机制的有效性，例如环境服务付款，以促进采用 SOC 增强实践。