INFLUENCE OF CLIMATE CHANGE ON SOIL DEGRADATION IN ARID ZONES OF THE VOLGA REGION
Gubarev D.I., Levitskaya N.G., Derevyagin S.S. INFLUENCE OF CLIMATE CHANGE ON SOIL DEGRADATION IN ARID ZONES OF THE VOLGA REGION // Arid ecosystems. 2022. V.28. № 1 (90). P. 20-27. | PDF
The aim of the research was to establish the impact of climate change on the processes of soil degradation and desertification in the arid zones of the Volga region. The material for the research was the observational data for 1971-2020 on 20 meteorological stations, as well as the results of soil-ecological and hydrogeological monitoring at research stations of the Federal State Budgetary Scientific Organization «Federal Center of Agriculture Research of the South- East Region» in the prevailing soil and climatic zones on the territory of the Saratov region (forest-steppe, steppe, dry steppe and semi-desert). Identified signs accompanying aridization, desertification and land degradation differentiated by natural zones. In particular, the average annual air temperature increased, compared with the climatic norm, by 1.0-1.2°С, the greatest increase was observed in August (by 2.0-2.2°С). The average temperature of the soil surface during the warm period increased by 1.1-1.5°C. The risks of severe atmospheric droughts during the entire growing season increased throughout the entire territory, most noticeably in the semi-desert zone (from 55 to 82%). The amount of precipitation in the spring increased by 10-25%, and in the summer – decreased by 23-30%. The boundaries of the semi-desert zone have shifted to the north and northwest. The tendency of changes in the hydrological regime of zonal soils from non-leaching to periodically leaching in 20-40% of years is outlined. The values of the aridity indices of the territory, calculated for the period from 2001 to 2020, increased in comparison with the climatic norm for 1971-2000 by 3-6%. This is an indicator of an increase in climate aridity during its current warming. As a result, high rates of dehumification (decrease in the relative humus content by 21-35%) and changes in the structural state of the arable layer and grain size distribution (decrease in water-resistant aggregates >0.25 mm from 39 to 31.8% and the absolute content of physical clay by 7.5%). At the same time, there is an increase in the mineralization of groundwater from 2500 to 7000 mg/l, as well as an increase in the content of toxic salts in the soil solution. Thus, the content of Cl—, SO42— ions in the places of replenishment with groundwater increased from 0.27 to 0.56 mg/eq. and from 0.27 to 13.27 mg/eq. respectively. The cation values also increased: Ca2+ – from 0.30 to 4.41 mg/eq., Mg2+ – from 0.12 to 5.59 mg/eq., The sum of K+ and Na+ – from 0.09 to 0.28 mg/eq. In the lowered elements of the relief, the development of processes of local salinization and waterlogging is noted.
Keywords.Climate change, aridization, drought, degradation, salinization.
Financing. The article was made within the state assignment No. 0751-2019-0008 “To develop theoretical foundations for structuring agricultural landscapes, adapting them to climatic and geomorphometric features of the territory in order to preserve and optimize the use of land resources to obtain an economically reasonable level of quality agricultural products”.