Molecular composition of water-extractable organic matter in chernozem soils during barley cultivation in a vegetation experiment

The aim of this study was to assess the impact of barley (Hordeum vulgare L.) vegetation on the molecular composition of water-extractable organic matter (WEOM) in chernozem soils. The study employed a vegetation experiment method in a climate chamber, with soil samples taken before sowing and during barley vegetation. The molecular composition of WEOM was analyzed using gas chromatography-mass spectrometry (GC-MS). Based on the obtained data, the Shannon diversity index was calculated, and the contribution of different compounds to the composition of WEOM was evaluated. It was shown that barley vegetation increases the complexity of the WEOM composition in chernozem. The molecular composition of WEOM varied for all experimental conditions. The proportion of lipids and nitrogen-containing compounds in WEOM of chernozem decreased during barley vegetation compared to its pre-sowing state, which may be associated with their active microbial decomposition. There was a significant increase in the proportion of carbohydrates in the WEOM composition of chernozem during barley vegetation. The obtained data indicate the high sensitivity of the molecular composition of WEOM in chernozem soils to the influence of barley functioning and rhizospheric microorganisms.