The urgency of the research is due to the fact that mobility of such essential microelements as Zn and Cu determines nutritional conditions for plants. The same elements, along with Pb, are reckoned among most distributed heavy metals which mobility determines safety of vegetative production. The aim of this work is to study the content and composition of Zn, Cu and Pb compounds in soils of natural landscapes of the Rostov region. The study was carried out on the virgin plot of heavy loam ordinary chernozem. The total content of microelements in topsoil layer (0–20 cm) was investigated by X-Ray Fluorescence (XRF) analysis. Mobile forms of Zn, Cu and Pb were determined in three parallel extracts: 1 N AAB (acetate-ammonium buffer) at pH 4.8; 1 % EDTA (ethylenediaminetetraacetic acid) in AAB at pH 4.8; and 1 N HCl. These extracts enable to determine exchangeable, complex, and specifically adsorbed forms of chemical elements in soil. To reveal the role of soil components in metal binding, sequential extraction procedure by Tessier et al. was used. Total content of Zn, Cu and Pb in soil shows the background level and doesn’t exceed maximum allowable concentration of the given elements. The specific characteristic of ordinary chernozem is low mobility of metals due to the presence of micellar forms of carbonates. The least content of exchangeable compounds among considered elements belongs to Zn. The mobile forms of Zn, Cu and Pb mainly represented by specifically adsorbed forms. It is established that the elements under study in ordinary chernozem mainly accumulate in clay minerals. Fractional composition of metals showed their close connection with organic matter and Fe-Mn oxides.
Keywords: zinc, copper, lead, ordinary chernozem, composition of compounds, mobility.
