Influence of soil moisture availability on dissolved organic matter properties and microbial carbon content in Poa pratensis L. rhizosphere

Abstract

The goal of the work was to assess changes in microbial carbon content and the properties of dissolved organic matter (DOM) of the Poa pratensis L. rhizopshere in response to the effects of soil drying and waterlogging. The vegetation experiment without plants and with dense sowing in vegetative vessels on Haplic Chernozem surfacewas used in the work. The properties of dissolved organic matter were evaluated based on the study of water-extractable organic matter (WEOM), in which the optical properties were assessed by UV-Vis spectrophotometry and spectrofluorimetry. Soil microbial carbon content was assessed by fumigation method. It has been shown that microbial carbon content in the bulk Chernozem does not depend on soil moisture, while in the rhizosphere it increases with drying and decreases with optimal and excess moisture. Soil moisture greatly affects WEOM properties of the bulk Chernozem, whereas the rhizosphere properties are influenced by the activity of the plant. Despite the lower microbial biomass compared to the bulk soil, the microbiome of P. pratensis L. rhizosphere is capable of more intense transformation of soil organic matter. The dynamic properties of P. pratensis L. rhizosphere ensure its more active and sustainable functioning compared to bulk soil.