title: Highly stable rice-straw-derived charcoal in 3700-year-old ancient paddy soil: evidence for an effective pathway toward carbon sequestration.
abstract: Recalcitrant charcoal application is predicted to decelerate global warming through creating a long-term carbon sink in soil. Although many studies have showed high stability of charcoal derived from woody materials, few have focused on the dynamics of straw-derived charcoal in natural environment on a long timescale to evaluate its potential for agricultural carbon sequestration. Here, we examined straw-derived charcoal in an ancient paddy soil dated from ~3700 calendar year before present (cal. year BP). Analytical results showed that soil organic matter consisted of more than 25% of charcoal in charcoal-rich layer. Similarities in morphology and molecular structure between the ancient and the fresh rice-straw-derived charcoal indicated that ancient charcoal was derived from rice straw. The lower carbon content, higher oxygen content, and obvious carbonyl of the ancient charcoal compared with fresh rice straw charcoal implied that oxidation occurred in the scale of thousands years. However, the dominant aromatic C of ancient charcoal indicated that rice-straw-derived charcoal was highly stable in the buried paddy soil due to its intrinsic chemical structures and the physical protection of ancient paddy wetland. Therefore, it may suggest that straw charcoal application is a potential pathway for C sequestration considering its longevity.
authors: Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
authors: Mengxiong
authors: M
authors: Wu
authors: Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.|State Grid Anhui Economic Research Institute, Hefei, 230031, China.
authors: Min
authors: M
authors: Yang
authors: Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
authors: Xingguo
authors: X
authors: Han
authors: Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
authors: Ting
authors: T
authors: Zhong
authors: Zhejiang Provincial Institute of Cultural Relics and Archaeology, Hangzhou, 310014, China.
authors: Yunfei
authors: Y
authors: Zheng
authors: Zhejiang Provincial Institute of Cultural Relics and Archaeology, Hangzhou, 310014, China.
authors: Pin
authors: P
authors: Ding
authors: Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China. weixiang@zju.edu.cn.
authors: Weixiang
authors: W
authors: Wu
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000378:metabolism; D057965:Carbon Sequestration; D002606:Charcoal / Q000737:chemistry*; D012275:Oryza; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D002606:Charcoal; D002244:Carbon
keywords: Ancient charcoal; Carbon sequestration; Oxidation; Rice-straw-derived charcoal; Stability