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Charcoal Carbon in U.S. Agricultural Soils
Author(s) -
Skjemstad Jan O.,
Reicosky Donald C.,
Wilts Alan R.,
McGowan Janine A.
Publication year - 2002
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2002.1249
Subject(s) - charcoal , soil water , environmental science , environmental chemistry , total organic carbon , carbon fibers , chemistry , soil science , mineralogy , materials science , organic chemistry , composite number , composite material
High levels of charcoal C resulting from repeated historical burning of grasslands, open woodlands, and agricultural crop residues have been reported in soils from Australia and Germany. In this study, five U.S. soils were selected from long‐term research plots in widely different agricultural areas. The charcoal C content was estimated on each soil using a combination of physical separation, high energy photo‐oxidation and solid‐state 13 C nuclear magnetic resonance (NMR) spectroscopy. These analyses showed that all five soils contained measurable amounts of charcoal C, <53 μm in size and ranging from 1.8 to 13.6 g C kg −1 soil and constituted up to 35% of the soil total organic C (TOC). Scanning electron microscopy showed that the charcoal material had a plant‐like morphology but were blocky and had fractured edges. These particles were similar in morphology to those separated from Australian and German soils. The implications of this material, which must be highly resistant to microbiological decomposition, to the soil C cycle are discussed.