English 
Русский 
A 700 km long soil transect in the south of the Russian Plain has been studied
A group of geologists, geographers and soil scientists from Pushchino has conducted a large comprehensive study devoted to the influence of climate on the chemical composition of chestnut and brown semi-desert (semiarid) soils.
Scientists have shown for the first time what processes occur in soils on the boundary between the steppe and desert zones under the influence of climate change. Significant clarifications were made to the mechanisms of migration of chemical elements and calculation of weathering coefficients for soils developed in an arid climate. The results of this work were published in the journal Catena.
The study has important practical significance. To reconstruct the climate of the past, quantitative assessment of weathering in ancient soils is often used. The greater the intensity of destruction of minerals and removal of chemical elements, the greater the degree of weathering is characterized by the soil. Therefore, the intensity of chemical weathering is a marker of increasing atmospheric humidity.
There are equations calibrated for modern soils based on weathering indices that allow estimating the amount of precipitation. Such equations are an important tool for assessing the dynamics of climate in the past and its impact on the soil cover in the future. However, calibrations are made mostly for wet (humid) soils. Soils of more arid regions are poorly studied in this aspect.
"Our work examined a 700 km long soil transect in the south of the Russian Plain in the Volgograd and Rostov regions and the Republic of Kalmykia. Average annual precipitation within the transect varies from 160 to 400 mm/year, average annual temperature from + 6 to + 9 °C. Chestnut and brown semi-desert soils with rather sparse vegetation are common here. This is the driest region of Russia. As a result of the research, it turned out that we cannot use geochemical coefficients calculated for humid soils when assessing weathering in arid regions, since we underestimated the recycling of salts in these soils" - said the author of the article, PhD in Geology and Mineralogy, Senior Researcher at the Laboratory of Soil Geochemistry and Mineralogy of the Institute of Physics and Biological Problems of Soil Science of the Russian Academy of Sciences Pavel Kalinin.
The study showed that the semi-arid soils of the Russian Plain are characterized by low intensity of modern chemical weathering processes. The degree of weathering is, for the most part, inherited from the parent rocks of the Quaternary age. Conditions for acid hydrolysis arise only in the upper horizons in an environment of increased biochemical activity and lower pH values.
The work was supported by the Russian Foundation for Basic Research (No. 19-29-05178, No. 19-54-45008).
Source: P.I. Kalinin, I.Yu. Kudrevatykh, V.V. Malyshev, L.S. Pilguy, A.V. Buhonov, G.V. Mitenko, A.O. Alekseev. Chemical weathering in semi-arid soils of the Russian plain. Catena 206 (2021) 105554.
https://doi.org/10.1016/j.catena.2021.105554
