Black Carbon Humic Substances: Do They Exist?.

Abstract

Charring of plant biomass has been suggested to play an important role in the humification of black carbon (BC) and soil organic matter by yielding high quantities of black humic substances (HS) such as humic acids (HAs) (Kumada, 1983; Shindo, 1986). However, BC HS have not been directly observed at the fine-scale. We used scanning transmission X-ray microscopy (STXM) coupled with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to investigate whether black carbon HS signatures could be observed in maps of intact soil aggregates as distinct from microbial or plant C.