The influence of soil characteristics on the lability and bioavailability of zinc at both background and phytotoxic concentrations in Albic Retisol soil (Loamic, Ochric) was studied using various methods. Ranges of insufficient, non-phytotoxic, and phytotoxic zinc concentrations in soil solutions were established in an experiment with an aqueous barley culture. It was experimentally revealed that for a wide range of non-toxic concentrations of Zn in the soil corresponding to the indicative type of plant response, there was constancy of the concentration ratio (CR) and concentration factor (CF) migration parameters. As a result, a new method for assessing the buffer capacity of soils with respect to Zn (PBCZn) is proposed. The transformation processes of the chemical forms and root uptake of native (natural) zinc contained in the Albic Retisol (Loamic, Ochric) through the aqueous culture of barley were studied using a cyclic lysimetric installation and radioactive 65Zn tracer. The distribution patterns of Zn(65Zn) between different forms (chemical fractions) in the soil were established using the sequential fractionation scheme of BCR. The coefficients of distribution and concentration factors of natural Zn and 65Zn, as well as accumulation and removal of the metal by plants were estimated. The values of the enrichment factor of natural (stable) Zn contained in sequentially extracted chemical fractions with the 65Zn radioisotope were determined and the amount of the pool of labile zinc compounds in the studied soil was calculated.
Keywords: 65Zn; barley; forms; labile zinc pool; lability; potential buffer capacity; soil; soil solution; specific activity; zinc.