The role of plant in the formation of the topsoil chemical composition in different climatic conditions of steppe landscape

Background and aims We assessed biomass variability and uptake of major and trace elements in different plant families of steppe landscapes under conditions of the geochemical properties of soils and the climatic parameters variability. The data obtained will contribute to a better understanding of the geochemical function of plants in steppes, which is crucial for predicting the response of landscapes to climate change. Methods Plant and soil samples were taken in different types of dry steppes (southeast of Russia) along a climatic gradient. In the obtained samples, the contents of Ca, K, Al, S, Mg, P, Cl, Fe, Ti, Zn, Mn, Cr, Sr, Ba and Rb were determined. Soil grain size, pH, carbonates (CaCO 3 ) and soil organic carbon (SOC) were determined. Results Increased mean annual precipitation and decreased temperatures contributed to the predominance of graminoid species, thus facilitating the accumulation of the studied major and trace elements in the upper soil horizons. Climate desiccation promoted the growth of wormwood and goosefoot in the ground cover, increased the alkalisation of the upper soil horizons and contributed to the accumulation of Ca, K, P, S and Cl by these plants. The contribution of plants to the total contents of Rb, Ti, Fe, Ca, P, Mg and S in the soil was higher in arid landscapes, where the ground cover was dominated by Asteraceae and Amaranthaceae, which may promote the accumulation of those elements in the upper soil horizons under the increasing trend of desiccation. Conclusions Our data confirm that the biodiversity of steppe vegetation, that is mainly determined bythe ratio of heat and moisture, affects the chemical properties of soils. This should be taken into account when assessing the environmental effects of further climate warming, given that desiccation will cause an increase in the contents of Ca, K, P, S and Cl in plants and soils.