Fire-derived organic carbon in soil turns over on a centennial scale

[摘要] Pyrogenic carbon (PyC), the residue of an incomplete combustion of biomass,is considered as a carbon (C) sink due to its assumed stability in soil. PyCturnover time estimated using two modelling approaches, based on data from 16published studies (n = 54) on PyC degradation, ranged from a decadal tocentennial time scale, varying with initial biomass type, pyrolysistemperature, and incubation or field study. The average turnover time using a one-poolapproach was 88 y, and the best estimate using a two-pool approach was 3 y for a fast-cycling pool and 870 y for a slow-cycling pool. Based onthis meta-analysis, PyC cannot be assumed to persist in soils for thousandsof years, and its use as a strategy for offsetting carbon emissions requiresprudence and further research.

[学科分类] 地球化学与岩石