Архив метки: degradation

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

SPECTRAL CHARACTERISTICS OF DESERTIFICATED PASTURES OF BLACK LANDS (KALMYK REPUBLIC)

Arid Ecosystems

UDC 631.1: 631.4:631.6:581.5: 528.7:528.8:574.46

Yuferev V.G., Tkachenko N.A., Sinel’nikova K.P. SPECTRAL CHARACTERISTICS OF DESERTIFICATED PASTURES OF BLACK LANDS (KALMYK REPUBLIC) // Arid ecosystems. 2022. V.28. № 1 (90). P. 65-72. | PDF

Geosystems of the desert territories of Kalmykia in modern conditions function in conditions of increasing anthropogenic impact and intensity of negative weather events, including the impact of dust storms, which often leads to a significant decrease in pasture productivity, a decrease in the feed base and a significant reduction in livestock. In this regard, it is relevant to determine the spectral characteristics of desert pastures by ground methods, which provides not only the detection of the reflected energy distribution over the spectrum frequencies, which in itself is important for subsequent verification of remote sensing data of pastures, but also the possibility of obtaining the values of normalized indicators, both for plant communities and for specific plants and soil types with the formation of a spatial data base. The objects of the study are the natural phytocenoses of desert pastures of the Black Lands at the landfills: «Smushkovo»,  «Molodezhny», «Privolny», «Dl. Sagi» and «Tavn-Gashun». Geobotanical and spectrometric studies were carried out at these polygons and spatially determined data on the spectral characteristics of plant communities were obtained. Spectrometric studies of phytocenoses are carried out to assess their condition on the basis of spectrosonal surveys, both ground-based and remote. To present the results of the assessment of the spectrometric characteristics of the vegetation cover of the downed pastures: the predominant communities at the landfill and «Tavn-Gashun» were selected: bluegrass with Descurania sofia (Poa bulbosa+Descurainia sophia) with a projective cover of 45%, grasshopper bluegrass (Poa bulbosa-Stipa capillata) – with a projective cover of 40% and open soil (slightly humus sand). The studies were carried out using the PSR-1100 field spectroradiometer. The results of studies of the spectrum of reflected radiation of plant communities and underlying soils allowed us to establish the characteristic features of the distribution of reflected and absorbed energy, to compile a catalog of individual spectra and normalized indicators for them. Individual spectral characteristics were established for the phytocenosis Poa bulbosa+Descurainia sophia, the average value of reflected energy in all spectral ranges is 20.2 MW/(m2×sr×nm), the standard deviation of reflected energy is 9.90, the vegetation index NDVI = 0.208, for Stipa capillata, the average value of reflected energy in all spectral ranges is 20.5 MW/(m2 sr nm), the standard deviation of reflected energy is 12.36, the vegetation index NDVI = 0.316, for Calligonum aphyllum, the average value of reflected energy-the reflected energy in all spectral ranges is 47.2 MW/(m2×sr×nm), the standard deviation of reflected energy is 9.81, the vegetation index NDVI = 0.354. For soil, the average value of reflected energy in all spectral ranges is 30.3 MW/(m2×sr×nm), the standard deviation of reflected energy is 9.28, the vegetation index NDVI = 0.106. The highest average value of NDVI was noted for Calligonum aphyllum.

Keywords: geosystem, analysis, desertification, degradation, spectrometry, satellite images, phytocenoses, verification, vegetation indices, albedo.

Financing. The work was carried out within the framework of the State Task of the Federal Research Center of Agroecology of the Russian Academy of Sciences No. 0713-2019-0001 “To conduct theoretical and geoinformation modeling, monitoring, forecasting of degradation processes of components of agroforestry landscapes based on aerospace research in forest-steppe, steppe and desert zones and to develop ways to manage anti-degradation agroforestry technologies to prevent desertification of lands, increase their fertility and form an ecological framework” (state registration No. AAAAAA-A-116122010038-9).

DOI: 10.24412/1993-3916-2022-1-65-72

GEOINFORMATION ANALYSIS OF DESERTIFICATION IN NORTH-WESTERN PRECASPIAN REGION

Arid Ecosystems

Kulik K.N.,  Petrov V.I.,  Yuferev V.G.,  Tkachenko N.A.,  Shinkarenko S.S. GEOINFORMATION ANALYSIS OF DESERTIFICATION IN NORTH-WESTERN PRECASPIAN REGION // Arid ecosystems. 2020. V. 26. № 2 (83). P. 16-24. | PDF

An analysis of the desertification of the North-Western Precaspian region using geo-information technologies and aerospace data to identify changes in the area of hotspots of desertification showed that the area of degraded and deserted lands increases with the growth in the quantity of sheep and goats. With a relatively stable number of animals, the role of climatic factors increases, which leads to an increase in the speed and amplitude of changes in the area of hotspots of desertification, both in the direction of decrease, with sufficient moisture, and an increase in dry years. Landscape fires have a significant impact, which lead not only to a decrease in the projective cover, but also to the depletion of the species composition of vegetation. The study and mapping of the relief made it possible to establish spatially determined geomorphological features of the territory as a factor affecting local moisture, and, accordingly, on the stability of ecosystems and the possibility of phytomelioration.

Keywords: geographic information systems, analysis, desertification, degradation, mapping, modeling, satellite imagery, hotspots, area, correlation, regression, phytomelioration.

DOI: 10.24411/1993-3916-2020-10091

LAND DEGRADATION OF THE REPUBLIC OF KALMYKIA: PROBLEMS AND WAYS TO RECOVER

Arid Ecosystems

Dedova E.B.,  Gol’dvarg B.А., Tsagan-Mandzhiev N.L. LAND DEGRADATION OF THE REPUBLIC OF KALMYKIA: PROBLEMS AND WAYS TO RECOVER // Arid ecosystems. 2020. V. 26. № 2 (83). P. 63-71. | PDF

The Republic of Kalmykia is located in the European part of the arid zone of the Russian Federation, where one of the serious environmental and socio-economic problem is the desertification of a significant part (up to 80 %) of its territory. So, from 6264 thousand hectares of agricultural lands 77.9 % is subjected to various types of degradation, from them waterlogged-93.96 thousand hectares, eroded-526.18 thousand hectares, deflated-1753.92 thousand hectares, salinized-2505.6 thousand hectares. The highest indices of deflationary degradation are observed in the South-Eastern regions of Kalmykia (IDD 31.7-71.1 points), which is due to natural (increased aridity of the climate) and anthropogenic (excessive pasture load) factors. The conceptual model reflecting the mechanism of meliorative influence on the degradation processes proceeding on the lands of agricultural use under the influence of natural and anthropogenic factors is developed. An agrobiological method of phytomelioration of degraded lands on open sand massifs is proposed, including planting of leafless juzgun (Calligonum aphyllum (Pall.) Gurke.), giant hair (Leymus racemosus Lam. Tzvel.), prostrate rod (Bassia prostrata (L.) A. J. Scott), grey teresken (Krascheninnikovia ceratoides (L.) Gueldenst.) and Siberian Wheatgrass (Agropyron sibiricum (Willd.) P. Beav.). The complexes of reclamation measures are developed. They are differentiated for different categories of agricultural lands, providing the creation of optimal conditions for increasing the natural resource potential of arid ecosystems and aimed at preventing desertification, leveling the complexity of the soil cover, reducing natural and anthropogenic salinity, salinity and the risk of other negative processes.

Keywords: degradation, soils, deflation, secondary salinization, pastures, phytomelioration, complex melioration, Kalmykia.

DOI: 10.24411/1993-3916-2020-10097

MELIORATIVE EFFICIENCY OF THE BELT OF SHRUBS ON THE ARID PASTURES OF SOUTHERN RUSSIA

Arid Ecosystems

Tyutyuma N.V., Bulakhtina G.K., Kudryashov A.V., Kudryashova N.I. MELIORATIVE EFFICIENCY OF THE BELT OF SHRUBS ON THE ARID PASTURES OF SOUTHERN RUSSIA // Arid ecosystems. 2020. V. 26. № 1 (82). P. 62-68 . | PDF

In this article we present the long-term study (2008-2018) of the influence of a belt of shrubs on the vegetation cover of semi-deserted and degraded pastures. We investigated the changes of snow cover depth during the winter period, productive soil moisture storage, species composition and arid pastures productivity in the dynamics of growth and development of the belt of shrubs. These experiments were carried out according to the methods developed by the All-Russian Research Institute of Agricultural Afforestation (1973), the All-Russian Research Institute of Forages (2015) and B.A. Dospekhov (1985). In comparison with a natural pasture without belts it was revealed that the snow cover depth was growing 3.5-11 times depending on the increased height of Krascheninnikovia shrubs and the amount of precipitation; soil moisture storage increased by 7.2-9.1 mm in the first 5 years, and by 8.8-24.8 mm when the belt’s height was more than 1 m; in the next 10 years the amount of dominant plant species increased by 4 species in the area with the belt of shrubs; pasture productivity increased 1.3-3.9 times in the 3rd years of Krascheninnikovia shrubs vegetation.

Keywords: phytocenosis of pastures, degradation, desertification, belt of shrubs, productive soil moisture storage.

DOI: 10.24411/1993-3916-2020-10084