Grasslands are a major terrestrial ecosystem type and store large amounts of soil organic carbon (SOC) per unit area. Quantitative and mechanistic knowledge on the effects of management on SOC stocks in grasslands is limited. Also, climate change can be seen as an indirect anthropogenic threat to SOC stocks, with warming effects on grassland SOC being currently understudied. Here, several studies investigating the effects of management and warming on SOC stocks are summarised, with a central to northern European focus. SOC sequestration increased with management intensity, i.e. cutting frequency and mineral fertilisation, even without external C inputs. This was partly explicable by increased productivity in more intensively managed grasslands. In addition, the availability of nutrients was found to foster microbial anabolism, leading to a more efficient build-up of SOC in fertilised as compared to unfertilised soils. Interestingly, the addition of 1 kg nitrogen as NPK fertiliser consistently led to approximately 1 kg of additional SOC. Sequestration of SOC might thus compensate for a major part of the increased greenhouse gas emissions associated with highly intensive grassland management. Including perennial grasses in agricultural crop rotations is multi-beneficial and proved to be a very efficient measure to increase SOC stocks. At the same time, soil warming depleted SOC, both in natural subarctic as well as in managed temperate grasslands. Climate change can thus be expected to counterbalance efforts of SOC build-up to some extent. Future research should focus on the interactive effects of climate change and management, which will be important for future management decisions.

中文翻译：

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沿管理强度和变暖梯度的草地土壤有机碳储量

草地是主要的陆地生态系统类型，每单位面积储存大量土壤有机碳（SOC）。关于管理对草原 SOC 储量影响的定量和机械知识是有限的。此外，气候变化可以被视为对 SOC 储量的间接人为威胁，目前对草地 SOC 的变暖影响尚未得到充分研究。在这里，总结了几项调查管理和变暖对 SOC 储量的影响的研究，重点是北欧的中心。即使没有外部碳输入，SOC 封存也随着管理强度（即切割频率和矿物施肥）而增加。这可以通过在集约化管理程度更高的草地上提高生产力来部分解释。此外，发现营养物质的可用性可促进微生物合成代谢，与未施肥的土壤相比，可更有效地在施肥土壤中积累SOC。有趣的是，添加 1 kg 氮作为 NPK 肥料始终会导致大约 1 kg 的额外 SOC。因此，固碳 SOC 可能弥补与高度集约化草地管理相关的温室气体排放增加的主要部分。在农作物轮作中加入多年生草是多方面的，并且被证明是增加 SOC 储量的非常有效的措施。与此同时，土壤变暖耗尽了自然亚北极和管理温带草原的 SOC。因此，气候变化有望在一定程度上抵消 SOC 建设的努力。未来的研究应侧重于气候变化与管理的相互作用，