An index-based approach to assessing recalcitrance and soil carbon sequestration potential of engineered black carbons (biochars). Academic Article uri icon


  • The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R(50), for assessing biochar quality for carbon sequestration is proposed. The R(50) is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R(50), with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiable relationship between R(50) and biochar recalcitrance. As presented here, the R(50) is immediately applicable to pre-land application screening of biochars into Class A (R(50) 0.70), Class B (0.50 R(50) < 0.70) or Class C (R(50) < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, whereas Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R(50), to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars.

published proceedings

  • Environ Sci Technol

altmetric score

  • 1

author list (cited authors)

  • Harvey, O. R., Kuo, L., Zimmerman, A. R., Louchouarn, P., Amonette, J. E., & Herbert, B. E.

citation count

  • 249

complete list of authors

  • Harvey, Omar R||Kuo, Li-Jung||Zimmerman, Andrew R||Louchouarn, Patrick||Amonette, James E||Herbert, Bruce E

publication date

  • February 2012