Caria G., Arrouays D., Dubromel E., Jolivet C., Ratié C., Bernoux Martial, Barthès Bernard, Brunet Didier, Grinand Clovis. (2011). Black carbon estimation in French calcareous soils using chemo-thermal oxidation method. Soil Use and Management, 27 (3), p. 333-339. ISSN 0266-0032.
Titre du document
Black carbon estimation in French calcareous soils using chemo-thermal oxidation method
Caria G., Arrouays D., Dubromel E., Jolivet C., Ratié C., Bernoux Martial, Barthès Bernard, Brunet Didier, Grinand Clovis
Source
Soil Use and Management, 2011,
27 (3), p. 333-339 ISSN 0266-0032
We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non-pyrogenic organic carbon in a furnace at 375 degrees C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC determination only in calcareous soils. Decarbonation changes the thermal properties of organic matter, creating more recalcitrant carbon than in the initial sample. Higher CaCO3 and organic carbon content results in a more pronounced artefact. The reversal of the first two steps of the chemo-thermal oxidation method (i. e. thermal oxidation before soil decarbonation) eliminates this artefact. Overall, our results suggest that BC content may have been overestimated in a large number of studies on calcareous soils.
