Evaluation of Silver Phytotoxicity on Soils of Different Stability: Brown Forest, Chernozem and Sierosands

The effect of silver pollution on the phytotoxicity of soils of varying degrees of resistance: chernozems, sierosands and brown forest soils was investigated. A direct relationship was observed between the concentration of the element in the soil and the length of the radish roots. At a silver concentration of 10 mg/kg, the highest toxicity was established on sulphurous sand and brown forest soil. A dose of 100 mg/kg had the greatest inhibitory effect on the length of the roots of radishes grown on ordinary chernozem, sierosands, and brown forest soil at 17, 24, and 29 % of the control, respectively. According to the degree of resistance to silver pollution, according to the radish root length indicator, the studied soils form the following series: ordinary chernozem (90) ≥ sierosands (88) > brown forest soil (81). The toxic effect of silver depends on the concentration of the element in the soil, the particle size distribution, the reaction of the soil environment and the content of organic matter in the soil. The greatest resistance of common chernozem to silver contamination is due to the particle size distribution, high humus content (3.7 %) and neutral alkaline-acid conditions (pH = 7.8). The light particle size distribution of the sierosands does not provide a sufficient absorption capacity for fixing silver in the soil. Brown forest soil is most sensitive to silver, as it has an acidic soil reaction (pH = 5.8), in which this element is mobile and has a toxic effect on the radish root system.