In this master work the influence of calcium ions on the cadmium mobility in the sandy and clay soils was investigated. Work subject - samples of Orthieutric Fluvisol and Calcaric-Endohypogleyic Luvisol topsoils taken from arable lands in Balbieriskis distirict. Work objective - to investigate the influence of calcium ions on the cadmium adsorption-desorption processes in the model systems of different kind of soil-Cd(NO3)2-Ca(NO3)2 simulating pH, Cd2+ and Ca2+ amounts. Work methods - the investigated soil samples were agitated for 1 hour with Cd(NO3)2 and Ca(NO3)2 solutions of various concentrations. The solutions were made in the 0.03M NaNO3 for the constant ionic strength maintaining. The Cd amounts in the equilibrium solution after the adsorption were determined with atomic absorption spectrometer (AAS). The Cd desorption was investigated in the samples after adsorption using 0.05M NH4-EDTA (pH 7) solution as extractant. The Cd amount in extract was determined with AAS. Work results - results of the research showed that in the clay soil were accumulated more mobile Cd ions under the influence of Ca ions than in the sandy soil. The clay soil adsorbed for 25 % less and desorbed for 77 % more mobile Cd ions than sandy soil. When soil contamination with Cd was increased from 8 till 40 mg/kg, the Cd adsorption increased about 17 % in both alkaline (pH 8) and acidic (pH 4) medium, while in the sandy soil it decreased about 7 % at pH 8 and increased about 3 % at pH 4. The... [to full text]