Архив метки: aridization

INFLUENCE OF CLIMATE CHANGE ON SOIL DEGRADATION IN ARID ZONES OF THE VOLGA REGION

Arid Ecosystems

UDC 631.434.52:504.123(470.4)

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”.

DOI: 10.24412/1993-3916-2022-1-20-27

CHARACTERISTICS OF THE SPRING-SUMMER DROUGHTS DURING THE DRY AND WET PERIODS IN THE SOUTH OF EUROPEAN RUSSIA

Arid Ecosystems

Zolotokrylin A.N., Titkova T.B., Cherenkova E.A. CHARACTERISTICS OF THE SPRING-SUMMER DROUGHTS DURING THE DRY AND WET PERIODS IN THE SOUTH OF EUROPEAN RUSSIA // Arid ecosystems. 2020. V. 26. № 4 (85). P. 76-83. | PDF

Distribution patterns of spring and summer droughts characteristics during high and low annual humidification periods are studied in twelve federal subjects of the South of European Russia for the period 1901-2018. During this time, four periods of different humidification conditions (alternate more humid, dry, humid and again dry periods) with variable durations are observed through data on anomalies of the aridity index in seven regions: Kursk, Belgorod, Voronezh, Saratov, Volgograd, Rostov Oblasts and the Republic of Kalmykia. The draining period was noted in Samara and Astrakhan Oblasts from the beginning of 20th century until its middle. Then the draining period changed to more humid. The most frequent change of periods with different humidification conditions was observed in Stavropol Krai, where five alternate periods were distinguished. It was found that the frequency of spring and summer droughts is consistent with the long-period humidification conditions. According to data of the Standardized Precipitation Index (SPI), it increases during the dry period by an average of 1.5 times while the intensity of droughts rises insignificantly. The increased humidification conditions observed in every above-mentioned federal subject in the second half of the 20th century changed to drier conditions in the beginning of the 21st century. The spreading of drier conditions began from east regions. The development of the dry period of humidification in the 21st century is confirmed by a distribution of a negative NDVI trend throughout the territory. While the aridization trends are not statistically significant in the regions of the South of European Russia in more than a century, there are prolonged interdecadal periods of aridizational strengthening and weakening, which are characterized by significant differences in frequency and intensity of spring and summer droughts.

Keywords: humidification periods, aridization, aridity index, droughts, SPI, NDVI.

DOI: 10.24411/1993-3916-2020-10121

DYNAMICS OF LAND DEGRADATION IN THE ROSTOV REGION

Arid Ecosystems

Bezuglova O.S.,  Nazarenko O.G., Ilyinskaya I.N. DYNAMICS OF LAND DEGRADATION IN THE ROSTOV REGION // Arid ecosystems. 2020. V. 26. № 2 (83). P. 10-15. | PDF

The Rostov region, located in the southeast of the European part of the Russian Federation, is characterized by a temperate continental climate with somewhat unstable humidity levels. Typical summers are dry and hot, while winters have relatively little snow and constant winds. Climatic and geomorphological features of the territory, as well as the high agricultural development of land resources determine the development of a number of deterioration processes. The purpose of the research was to make a comparative spatio-temporal assessment of degradation processes that contribute to the development of the desertification process in the Rostov region. The basis of the research was the analysis of literature and archival data in retrospect, the use of calculated natural and environmental indicators, differentiated study of soil types common for the region and the degree of natural humidity of the agrolandscape in accordance with the ecological stability and hydrothermal regime of the territory. It has been established that the climate aridization, agro-depletion, erosion development are typical for the Rostov Region. This allows for evaluation Rostov region as a territory with a risk of potential desertification.

Keywords: dehumification, agro-depletion, erosion, aridization, desertification.

DOI: 10.24411/1993-3916-2020-10090

TIME AND REASONS OF SOLONETZ PROCESS’ GENESIS IN THE SOILS OF THE DESERTED STEPPES IN THE SOUTHEASTERN PART OF EAST EUROPEAN PLAIN

Arid Ecosystems

Borisov A.V., Alekseyev A.O. TIME AND REASONS OF SOLONETZ PROCESS’ GENESIS IN THE SOILS OF THE DESERTED STEPPES IN THE SOUTHEASTERN PART OF EAST EUROPEAN PLAIN // Arid ecosystems. 2020. V. 26. № 1 (82). P. 33-42 . | PDF

In this article we study the time frame and role of the anthropogenic factor in the genesis of the solonetz process in the soils of the deserted steppes in the southeastern part of East European Plain. Basing on the research of the soils of different ages buried under the barrows of Bronze Age and Middle Ages (6200-700 years ago) in the boundaries of Sal-Manych ridge, we found out that before the 3rd millennium BC those soils had no signs of solonetz process on macro level. First solonetz in the region started to form 4800-4700 years ago, which chronologically matches the beginning of climate aridization intensification. During that period the deserted steppes were actively inhabited by cattlemen, who were breeding small cattle, which in its turn caused the pressure on land and steppe ecosystems. In this article we study the possible cause and effect relations in “climate – agricultural” model – solonetz process” system.

Keywords: desert-steppe zone, Sal-Manych ridge, soils, solonetz process, barrows, Bronze Age, aridization, cattle, grazing.

DOI: 10.24411/1993-3916-2020-10081