Carbon gain in upper but loss in deeper cropland soils across China over the last four decades

• 成果类型: Article
• 署名作者: Zhou, Zhenghu; Wang, Chuankuan; Li, Yu'e; Wang, Xuhui; He, Xinhua; Xu, Minggang; Cai, Andong
• 署名单位: Northeast Forestry University - China; Northeast Forestry University - China; Chinese Academy of Agricultural Sciences; Institute of Environment & Sustainable Development in Agriculture, CAAS; Peking University; Shanxi Agricultural University; University of Western Australia; University of California System; University of California Davis; Chinese Academy of Agricultural Sciences; Institute of Agricultural Resources & Regional Planning, CAAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12273
• DOI: 10.1073/pnas.2422371122
• 发表日期: 2025-01-07
• 关键词: organic-carbon; accumulation; management; increase; storage; matter; stocks; 1980S

摘要

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-2 y-1. 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.