Formation of microelement composition of soils of Stavropol krai under the influence of waterlogging processes

The object of the study was the hydromorphic soils of the Tashlyansky landscape of ravine forest-steppes, identified in the Stavropol Krai. The radial geochemical structure of differentiation of gross contents of Zn, Cu, Pb and Cd in the profile of meadow-chernozem soils formed under the influence of constant ground and seasonal surface moistening was studied. The features of lateral geochemi relation to the general lateral structure of migration of chemical elements, characteristic of the laid landscape-geochemical mesocatena within the Tashlyansky landscape, were also studied. The main methods were field and office analyses, analysis of scientific information on similar landscape-geochemical processes. The morphological characteristics and a number of physicochemical properties of meadow-chernozem soils have been established, which indicate the formation of differentiation in the soil profile by alkaline-acid conditions (there is a change from the neutral reaction of the environment in the humus horizon to a slightly alkaline one in the lower part of the soil profile) and oxidation-reduction conditions (there is a change from the oxidizing environment to a reducing gley environment). The radial differentiation structure of the total contents of Zn and Cu corresponds to the surface-accumulative distribution, which, together with the established statistically significant correlation coefficients with the humus content, indicates the fixation of Zn and Cu on the biogeochemical barrier as part of organomineral compounds. The radial differentiation structure of Pb and Cd is characterized by eluvial-illuvial distribution. The established correlation coefficients indirectly confirm the fixation of Pb and Cd as part of aluminosilicate clay minerals. Important phases-carriers of microelements in hydromorphic soils are oxides (hydroxides) of Fe and Mn, carbonates, easily soluble salts, which are visually determined in their profile. In the general picture of lateral differentiation of microelements along the landscape-geochemical mesocatena, meadow-chernozem soils act as low-contrast concentrators of Zn and Cu. More intensive radial migration of Pb and Cd from humus horizons in hydromorphic conditions affects the features of their lateral distribution along the landscape-geochemical mesocatena.

1. Motuzova G.V. Joints of microelements in soils: system organization, environmental significance, monitoring. Moscow: Book House “Librock”; 2009. 168 p. (In Russ.).

2. Vodyanitsky Yu.N. Natural and technogenic compounds of heavy metals in soils. Eurasian Soil Science. 2014;(4):420-432. (In Russ.). https://doi.org/10.7868/S0032180X14040108

3. Minkina T.M., Motuzova G.V., Nazarenko O.G. Composition of heavy metal compounds in soils Rostov-on-Don: Publishing house «Everest»; 2009. 208 p. (In Russ.).

4. Shcheglov D.I., Brekhova L.I. Soil formation processes. Voronezh: VSU Publishing House; 2016. 58 p. (In Russ.).

5. Shalnev V.A. Landscapes of Stavropol Krai. SGPU Publishing House; 1995. 52 p. (In Russ.).

6. Protasova N.A. Microelements in chernozems and gray forest soils of the Central Chernozem Region: author’s abstract dissertation of dr. boil. sciences: 03.00.27. Voronezh; 2002. 40 p.

7. Protasova N.A., Shcherbakov A.P. Microelements (Ti, Mn, Cr, V, Ni, Zn, Cu, Co, Mo, Be, Ba, Sr, Zr, Ga, B, I) in chernozems and gray forest soils of the Central Chernozem Region. Voronezh: Voronezh University Publishing House; 2003. 368 p. (In Russ.).

8. Gorbunova N.S., Protasova N.A. Forms of manganese, copper and zinc compounds in chernozems of the Central Black Earth Region. Proceedings of Voronezh State University. Series: Chemistry. Biology. Pharmacy. 2008;(2):77-85. (In Russ.).

9. Sosorova SB, Kashin VK. Lead in soils of the Selenga River delta. Eurasian Soil Science. 2021;(2):196-210.

10. Akhtyrtsev B.P., Akhtyrtsev A.B., Yablonskikh LA. Heavy metals and radionuclides in hydromorphic soils of the forest-steppe of the Russian Plain and their profile distribution. Eurasian Soil Science. 1999;(4):435-444.

11. Kulintsev V.V., Godunova E.I., Zhelnakova L.I., et al. New generation farming system of Stavropol Krai Stavropol: AGRUS of Stavropol State Agrarian University; 2013. 520 p. (In Russ.).

12. Dzybov DS. Vegetation of Stavropol Krai. Stavropol: AGRUS; 2018. 492 p. (In Russ.).

13. Dyachenko V.V. Geochemistry, systematics and assessment of the state of landscapes of the North Caucasus Rostov-on-Don: Complex; 2004. 268 p. (In Russ.).

14. Vinogradov A.P. Average content of chemical elements in the main types of igneous rocks of the earth's crust Geochemistry. 1962;(7):555-571. (In Russ.).

15. Vinogradov A.P. Geochemistry of rare and dispersed chemical elements in soils Moscow: Publishing house of the USSR Academy of Sciences; 1957. 238 p. (In Russ.).

16. Martinez C.E., Bazilevskaya KA, Lanzirotti A. Zinc coordination to multiple ligand atoms in organic rich surface soils Environ Sci. Technol. 2006;40: 5688-5695.

17. Grechishkina Yu.I. Preservation and reproduction of the fertility of chernozem soils to increase the productivity of agrocenoses of the Central Ciscaucasia: dissertation of dr agricult sciences: 06.01.04. Stavropol; 2020. 469 p.

18. Bargalyi R. Biogeochemistry of terrestrial plants: an ecophysiological approach to biomonitoring and biorestoration Edited by NS. Kasimov. Moscow: GEOS; 2005. 456 p. (In Russ.).

19. Covelo E., Vega F., Andrade M. Competitive sorption and desorption of heavy metals by individual soil components Journal of Hazardous Materials. 2007;140:308-315.

20. Ponizovsky A.A., Mironenko E.V. Mechanisms of lead (II) absorption by soils. Eurasian Soil Science. 2001;(4):418-429. (In Russ.).

21. Bradl H. Adsorption of heavy metal ions on soils and soils constituents Journal of Colloid and Interface Science 2004;277:1-18.

22. Zachara J.M., Cowan C.E., Resh C.T. Sorption of divalent metals on calcite Geochimica et Cosmochimica Acta 1991;55(6):1549-1562.

23. Degtyareva T.V., Solyannik E.N., Melnichuk V.V., Lyashenko E.A. Formation of microelement composition of soils of semi-desert landscapes of Stavropol Krai Science Innovations. Technologies. 2022;(2):73-88. (In Russ.). https://doi.org/10.37493/2308-4758.2022.2.4