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

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.

Short-term bioavailability of carbon in soil organic matter fractions of different particle sizes and densities in grassland ecosystems.

The quality, stability and availability of organic carbon (OC) in soil organic matter (SOM) can vary widely between differently managed ecosystems. Several approaches have been developed for isolating SOM fractions to examine their ecological roles, but links between the bioavailability of the OC of size-density fractions and soil microbial communities have not been previously explored. Thus, in the presented laboratory study we investigated the potential bioavailability of OC and the structure of associated microbial communities in different particle-size and density fractions of SOM.