The transfer of zinc (natural stable Zn and radioactive tracer 65Zn) to aqueous phase and its uptake by barley have been studied using a specially designed vegetation testbench comprising a lysimeter unit filled with coarse-textured soil and drainage and the vegetation vessels with aqueous barley culture. Although the zinc migration to soil aqueous phase and its uptake by plants are spatially separated, they are sequentially coupled. The patterns of Zn(65Zn) distribution among different compounds (chemical fractions) in soil were determined using parallel and sequential fractionation procedures. The relative content of native (stable) Zn in labile and conventionally labile forms is 2.1–6.5-fold lower as compared with the relative content of radionuclide 65Zn and, vice versa, 2.8–3.0-fold higher for conservative (fixed) fractions of the metal in soil. The dynamics of the following parameters were assessed: Zn concentration, 65Zn specific activity, distribution and concentration factors of natural Zn and 65Zn, and uptake and removal of the metal by plants. The enrichment factors of stable Zn, contained in sequentially extracted chemical fractions, with radioisotope 65Zn, were determined, and the pool of the labile zinc compounds in the studied soil was evaluated.

The influence of humidity of typical Chernozem on the acidity and cationic composition of various energy fractions of the equilibrium soil solution was studied. As the object of research, we used soil solutions extracted by pressure (PSS) from the samples of the arable horizon of typical Chernozem contaminated with Zn, after the completion of the growing experiment with the test culture – barley. The studies of the cationic composition and acidity of quasi-equilibrium soil solutions dependence on the humidity of Chernozem were carried out in the humidity range of 11–40%, i.e., in the range of productive moisture available to plants (pF: 2.17–4.45). For the PSS of variants "bare fallow" and "barley" (Zn0, Zn250 and Zn500), with a decrease in the residual humidity of the sample in the studied range, the concentration of the studied metals in the sequentially extracted PPR fractions also decreased. The acidity of the quasi-equilibrium PSS with increasing humidity (with dilution) decreased. The changes reached 2 pH units. For all the energy fractions of PSS, there was a decrease in acidity for the "barley" variants (Zn0, Zn250, Zn500) compared to the "bare fallow" variants.

From the samples of gradually drying (beginning from the field moisture capacity, FMC) soddy-podzolic sandy loam soil (Albic Retisol (Loamic, Ochric)) contaminated with Zn were isolated the soil solutions (SS) by centrifugation, while from the other samples of the soil, moistened to FMC, various energy fractions of the SS were pressed using a hydraulic press. The acidity of the centrifuge solutions extracted from the soil of the experiment variant with the cultivation of plants ("barley") was, on average, 1 pH higher than on "bare fallow", and decreased with decreasing soil moisture content. The acidity of the solutions extracted from the soils of the "bare fallow" variant in the same range of soil moisture content practically did not change. It was also found that in more acidic solutions from the "bare fallow" variant the content of Ca, Mg, Mn, Zn and K was 2.4 - 6.9 times higher than the content of these metals in solutions from the "barley" variant. The positive correlation between pF and pH was clearly observed for the pressed solutions from the soils of both variants. Concentrations of Ca, Mg, Sr, Ba,Zn, K and Na in successively pressed fractions of SSs from more acidic soil of the "bare fallow" variant, on average, 3.0 - 8.4 times exceeded their concentrations in similar fractions of solutions of the "barley" variant and showed an inverse correlation with soil moisture (pF value).

The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn 2+ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P) Zn ). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.

Data are given on the trace element composition of goat milk in stabling and pasturing periods of the animals in the Kaluga, Bryansk, and Lipetsk oblasts. The uptake of heavy metals from feed into milk and its characteristics are evaluated. The maximum content of biogenic and toxic elements in milk didn’t exceed the maximum allowable concentration, and exceeding of the maximum allowable level of Cd, Cr, Fe, and Al and low Co level in feed were established.