Microelementary Composition of Soils and Steppe Phytocoenoses in the Western Transbaikal Region

Abstract

The average concentrations of 17 microelements and their variation ranges have been determined in chestnut soils (Kastanozems) and the vegetation of steppe arid ecosystems in the western Transbaikal region. The average concentrations of Li, B, Al, Cr, Fe, Co, Zn, and Zr in the soils are consistent with their clarke values, which are accepted as environmental–geochemical standards. The concentrations of Mo, Ba, and Be are 1.8–2.9 times higher than their clarke values, and the concentrations of Cu, Ni, and Mn are lower than their clarke values, while the concentrations of V and Pb reach their maximum permissible levels. Мо, Zn, B, and Cu demonstrate the highest degree of biological absorption from the soil by plants; Li and Mn are absorbed to medium degree; and Be, Al, Ti, V, Cr, Fe, Co, Ni, Zr, Ba, and Pb are absorbed to a low degree. For V, Cr, Mn, Fe, Zn, Ba, and Pb, a correlation between their concentrations in the vegetation and soil has been established (r = 0.51–0.82), while there is no correlation (r = –0.08–0.39) for Li, Be, B, Al, Ti, Co, Ni, Cu, Zr, and Mo. A deficit of B, Zn, and Cu and higher concentrations of Fe, Mo, Ba, and Sr in the vegetation have been identified. The unfavorable ratios between essential elements have been determined. The contribution of the above-ground phytomass to the biogenic migration of microelements has been assessed.