Features of the chemical structure of different organic matter pools in Haplic Chernozem of the Streletskaya steppe: 13C MAS NMR study.

Features of the chemical structure of different organic matter pools in Haplic Chernozem of the Streletskaya steppe: 13C MAS NMR study. Environ Res. 2020 Sep 16;:110205 Authors: Danchenko NN, Artemyeva ZS, Kolyagin YG, Kogut BM Abstract The aim of the current research was to study structural features of four organic matter (OM) pools isolated by the modified method of granulo-densimetric fractionation from two Сhernozems. We purposed to relate these features to the OM allocation and the transformation processes. The pools included: 1) free light fraction located in an inter-aggregate space, 2) light fraction occluded inside the microaggregates, 3) OM bound with clay particles, and 4) OM bound with a residual heavy fraction left after light fractions and clay separation. Soils of contrasting land uses: steppe and long-term permanent bare fallow were selected to assess changes that occur in soil OM during the degradation. We used 13C CP/MAS NMR spectroscopy controlling the quantitativeness of spectra with the aid of 13C DP/MAS NMR. The obtained spectra of the studied fractions clearly differed in the proportion of main functional groups. The occluded OM is more aromatic compared to the free OM. The structural changes observed at transition from the free light fraction to the occluded one indicate an active decomposition of lignin and carbohydrates in the latter fraction. This provides in the occluded OM appropriate conditions for the ...
Source: Environmental Research - Category: Environmental Health Authors: Tags: Environ Res Source Type: research