Highly stable rice-straw-derived charcoal in 3700-year-old ancient paddy soil: evidence for an effective pathway toward carbon sequestration

• Published in: Environmental science and pollution research international Vol. 23; no. 2; pp. 1007 - 1014
• Main Authors: Wu, Mengxiong, Yang, Min, Han, Xingguo, Zhong, Ting, Zheng, Yunfei, Ding, Pin, Wu, Weixiang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2016; Springer Nature B.V
• Subjects: Agriculture; Aquatic Pollution; Archaeology; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Carbon - metabolism; Carbon Sequestration; Carbon sinks; Carbonyl compounds; Charcoal; Charcoal - chemistry; chemical structure; Climate change; Crop residues; Earth and Environmental Science; Ecological Assessment and Remediation (CLEAR 2014) Conference: Environmental Pollution and Remediation; Ecotoxicology; Electron microscopes; Environment; Environmental Chemistry; Environmental conditions; Environmental Health; Fourier transforms; Global warming; Historic buildings & sites; Land pollution; longevity; Molecular structure; Morphology; Natural environment; NMR; Nuclear magnetic resonance; Organic matter; Organic soils; Oryza; Oxidation; oxygen; paddies; paddy soils; Remediation; Rice; Rice fields; Rice straw; Selected Papers from the 2nd Contaminated Land; Soil - chemistry; Soil organic matter; Soil pollution; Soil remediation; Soils; Spectrum analysis; Straw; Waste Water Technology; Water Management; Water Pollution Control; wetlands; China; Rice-straw-derived charcoal; Oxidation; Stability; Carbon sequestration; Ancient charcoal
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-015-4422-x

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.