In situ quantification of soil organic matter by CP/MAS solid state 13C NMR
Solid state 13C NMR is an important analytical technique for the characterization of soil organic matter (SOM) in agricultural and forest ecosystems. There is considerable uncertainty, however, concerning the reliability of NMR spectra for the quantification of . functional groups in SOM. As part of the National Soil Conservation Program, a study was undertaken to define an analytical protocol to enable the quantification of soil c by CP/MAS 13C NMR in intact soil samples. This study indicated that the proportion of soil C observed by solid 13C-NMR varied between 79 and 103% of the soil organic C. The %C observed was described as a logarithmic function of the magnetic susceptibility/organic-C ratio. Aromatic-C in a cultivated Gleysol was 1.0 t ha-1 5 cm and it represented 9% of the total soil organic carbon. The proportion of c aromaticity in solid soil samples is lower than average values reported earlier for soil humic and fulvic acid fractions.
The following license files are associated with this item: