Microelement composition of sod-carbonate soils of the North-West caucasus

Abstract

The aim of the work is to study the peculiarities of the formation of the microelement composition of sod-carbonate soils of the North-West Caucasus. Methods: Determination of the features of the formation of the microelement composition of sod-carbonate soils was carried out in the western part of the Labino-Malkinsky landscape district of forest-steppes and settled meadows. The Kuestov District occupies a band of ridges of the Northwestern Caucasus, composed of limestones, dolomites and sandstones of the Jurassic (K) and Cretaceous (k) periods. Chemical analysis of the soil was performed by conventional methods. The content of strongly bound compounds Pb, Cu, Zn, and Cd by acid decomposition using 5 M HNO3 was analyzed in the humus horizon of soils. The metal content was determined by the methods of inversion volt-amperometric and atomic absorption analyses. Results: In most cases, the microelement composition of sod-carbonate soils is characterized by the enrichment of Pb, Cu, Cd and depletion of Zn in comparison with the Clark soils. The constant anthropogenic input of pollutants into the soil as a depositing medium directly affects the trace element composition-the soils are intensively enriched with all the elements considered, especially strongly accumulated on CD and PB. In the radial distribution of trace elements between sod-carbonate soils and the soil-forming rock, a high intensity of accumulation of chemical elements in the humus horizon of soils was revealed. The intensity of the redistribution of trace elements in soils is largely determined by the position in the terrain. Within the Cretaceous cuesta, high Cd contents are typical for plakor soils, Cu and Zn-for the soils of the slope of the beam. On the slope of the Jurassic questi higher contents of Pb, Cd and Cu are typical for soils of placorestan cavage array Zn for soils of steep hillside with oak and beech forests. Conclusions: The microelement composition of sod-carbonate soils is a consequence of such soil-forming processes as humification, humus accumulation, leaching, glinting, and loess age, the specifics of which are largely determined by calcium carbonates. The microelement composition of sod-carbonate soils reflects the most significant features of the microelement composition of soil-forming rocks, which are characterized by low Zn content. The possible aerotechnogenic intake of trace elements affects the intensity of the radial accumulation of trace elements in the soil relative to the rocks. The degree of transformation of the microelement composition of anthropogenic disturbed soils depends on the intensity of anthropogenic impact on the soil. The conducted research is important in the aspect of revealing the regularities of the formation of the microelement composition of the soil as a depositing component of the landscape in modern conditions of anthropogenic pressure