Zhou Zhenghu, Wang Chuankuan, Li Yu'e, Wang Xuhui, He Xinhua, Xu Minggang, Cai Andong
School of Ecology and Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China.
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Proc Natl Acad Sci U S A. 2025 Jan 7;122(1):e2422371122. doi: 10.1073/pnas.2422371122. Epub 2024 Dec 31.
Increasing soil organic carbon (SOC) in agricultural systems is a primary nature-based option for mitigating climate change, improving soil fertility, and ensuring food security. However, the consequences of global warming and increases in carbon inputs on cropland SOC stocks over the last few decades remain largely unknown, particularly in deeper soil layers. Here, by using repeated measurements, we reassess variations in SOC stocks across a 0 to 100 cm soil profile at the same locations in China's upland croplands in 1980 and 2023. We observe an overall net accumulation of 0.74 Pg SOC (7%) with a mean sequestration rate of 13.7 g SOC m y. This accumulation results from 0.86 Pg SOC gains at upper soil depths (0 to 60 cm) induced by carbon inputs, alongside 0.12 Pg SOC losses at deeper soil layers (60 to 100 cm) prompted by warming-enhanced decomposition. While our findings indicate a successful, though lower than expected, increase in overall net SOC stocks, the loss of more recalcitrant deeper SOC warrants further consideration of its effects on enhancing cropland SOC accumulation to achieve carbon neutrality over the long term.
增加农业系统中的土壤有机碳（SOC）是缓解气候变化、提高土壤肥力和确保粮食安全的主要基于自然的选择。然而，过去几十年全球变暖和碳输入增加对农田SOC储量的影响在很大程度上仍不明确，尤其是在较深的土壤层中。在这里，我们通过重复测量，重新评估了1980年和2023年中国旱地农田相同位置0至100厘米土壤剖面中SOC储量的变化。我们观察到SOC的总体净积累量为0.74Pg（7%），平均固存率为13.7克SOC/平方米/年。这种积累是由碳输入导致的上层土壤深度（0至60厘米）0.86Pg的SOC增加，以及变暖增强的分解导致的深层土壤层（60至100厘米）0.12Pg的SOC损失共同造成的。虽然我们的研究结果表明总体净SOC储量成功增加，尽管低于预期，但更难分解的深层SOC的损失值得进一步考虑其对长期增强农田SOC积累以实现碳中和的影响。
