DISSOLVED ORGANIC MATTER OF CHERNOZEMS OF DIFFERENT USES: THE RELATIONSHIP OF STRUCTURAL FEATURES AND MINERAL COMPOSITION

Abstract

Structural peculiarities of the organic component of dissolved organic matter (DOM) of typical chernozems (Protocalcic Chernozem), dif ering in the principal direction of soil organic matter transformation (accumulation or mineralization), has been analyzed in relation to the mineral composition of DOM. To characterize the structural features of the organic component, spectrometry in the ultraviolet and visible range and f uorescence spectroscopy were applied as approaches most of en used for these purposes due to the expressiveness and accessibility of the instrumental design. T e content of mineral elements (Al, B, Ba, Ca, Fe, K, Li, Mg, Mn, Na, P, S, Si, Zn) was carried out by optical emission spectrometry with inductively coupled plasma. DOM of arable chernozems, where the mineralization of organic matter is the prevalent process of organic matter transformation, was found to possess higher values of the indexes E2/E3, BIX and SUVA254. T e latter indicates a smaller MM, a greater contribution of organic matter of microbial origin and aromatic structures to the composition of DOM as compared to soils not involved in agricultural use. T e analysis of the mineral component showed Si and Ca were the most abundant elements in the DOM. T e involvement of chernozems in agricultural use resulted in a decrease in Ca content and an increase in Si, Fe and Al, what ref ected an increase in the degree of weathering of the mineral matrix of chernozems. T e conducted rank correlation analysis showed the presence of signif cant relationships between the structural characteristics of the DOM (E2/E3, SUVA254, MM, BIX, T) and the content of mineral elements (Ca, Al, Fe, Si) indicating the inf uence of weathering processes on the formation of the soil DOM.