The Loss-on-Ignition (LOI) method is used to estimate the organic matter (OM) content.
~1100 C for total carbon (SOC+SIC)
650 C method for SOC (Hoogsteen et al., 2015)
350-600 C for OM and SOC (see SSSA "big brown book" for LOI combustion times and temperatures).
References
Hoogsteen, M.J.J., Lantinga, E.A., Bakker, E.J., Groot, J.C.J. and Tittonell, P.A., 2015. Estimating soil organic carbon through loss on ignition: effects of ignition conditions and structural water loss. European Journal of Soil Science, 66(2), pp.320-328.
Soil Survey Staff. 2014. Kellogg Soil Survey Laboratory Methods Manual. Soil Survey Investigations Report No. 42, Version 5.0. R. Burt and Soil Survey Staff (ed.). U.S. Department of Agriculture, Natural Resources Conservation Service.
Stoops, G., 2021. Guidelines for analysis and description of soil and regolith thin sections. John Wiley & Sons.
Soil organic carbon (SOC): The SOC content is typically measured using dry-combustion on an elemental analyzer (also N -- C/N). Alternatively, correction factors can be developed to convert LOI to SOC, which account for dehydroxylation of clay (Hoogsteen et al., 2015). *Our lab has found this approach typically overestimates SOC, compared to dry-combustion.
References
Hoogsteen, M.J.J., Lantinga, E.A., Bakker, E.J., Groot, J.C.J. and Tittonell, P.A., 2015. Estimating soil organic carbon through loss on ignition: effects of ignition conditions and structural water loss. European Journal of Soil Science, 66(2), pp.320-328.
Soil Survey Staff. 2014. Kellogg Soil Survey Laboratory Methods Manual. Soil Survey Investigations Report No. 42, Version 5.0. R. Burt and Soil Survey Staff (ed.). U.S. Department of Agriculture, Natural Resources Conservation Service.
We characterize the organic matter fragments in thin section using previously published micromorphology methods (Blazejewski et al., 2005; Stoops 2021). See Blazejewski et al. (2005) for details. Carbon forms are identified into classes: roots, fragmental organic matter, lenses, infillings, masses and horizons. Root decomposition is identified based on classes (0 to 4) outlined in Blazejewski et al. (2005, Table 3).
References
Blazejewski, G.A., Stolt, M.H., Gold, A.J., Groffman, P.M., 2005. Macro-and micromorphology of subsurface carbon in riparian zone soils. Soil Science Society of America Journal 69, 1320–1329.
Stoops, G., 2021. Guidelines for analysis and description of soil and regolith thin sections. John Wiley & Sons.