Архив рубрики: article-2-2022

SALINIZATION OF SOILS IN THE DON VALLEY UNDER CONDITIONS OF IRRIGATION CESSATION

Arid Ecosystems

UDC 631.4

Gorokhova I.N., Chursin I.N. Salinization of Soils in the Don Valley under Conditions of Irrigation Cessation // Arid ecosystems. 2022. V.28. № 2 (91). P. 102-112. | PDF

The presented study is aimed at identifying the current salinity state of the soils of the Generalovskiy Irrigation System (IS), built near the Tsimlyansk reservoir (1959) and located in the dry-steppe zone of the Volgograd oblast, in the Don Valley. The system is currently in the conditions of a 30-year period of cessation of irrigation. During the interpolation study, soil salinity maps were created, covering their different depths and based on field survey materials and water extraction data (1:5) of soil samples collected in 2020. Water extraction data obtained in the Volgograd Hydrogeological and Reclamation party (2018) were also used.

The key plot of the research was located on the 2nd left-bank terrace above the floodplain of the Don River and included the territory where by the beginning of the 1990s, during a long period of irrigation, a high level (1.5-3 m) and strong mineralization (3-10 g/l) of groundwater formed, which led to the forming of meadow solonchak and secondary salinized soils of a strong degree of salinity. This stimulated the salinization mapping of the territory and encouraged us to determine the changes happened during the past period.

The analysis of soil salinity maps made it possible to: assess the current salinity state of soils located on various elements of the topography of the second terrace of the Don River and comparison of the current salt state of soils with the period of the late 1980s and early 1990s, which showed the gradual salinization of previously saline areas and the development of alkalinization of the upper horizons of soils. Soil salinization is caused by the cessation of irrigation, and soil alkalinization is caused by the location of the Generalovskiy IS in the salt zone, a long period of irrigation (1960-1992) and irrigation from the Tsimlyansk reservoir with water with an increased concentration of sodium. Soil salinity maps showing the depth of the salt horizon provide information necessary for the development and selection of optimal reclamation measures to restore soil fertility.

Preliminary recommendations for solving this problem when irrigation is resumed may be: quality control of irrigation water, the use of periodic (every few years) spring water-supply washing of the 0-70 cm layer to push accumulated salts out of the aeration zone, plastering to ensure the displacement of exchangeable sodium, suppression of alkalinity and removal of water-soluble sodium into the underlying horizons beyond the root layer, the use of drip irrigation, an increase in the sharer of perennial legumes and cereals in the structure of planted acreage.

The impossibility of using spectral indices (given in the literature) to determine soil salinity with the help of satellite imagery in relation to the selected research area is shown in the article. A multiple regression analysis was carried out to confirm this. In this analysis, the values of spectral indices in four channels of the Sentinel-2 satellite image and the salinity values of different soil horizons at the sampling points obtained as a result of field and laboratory work were used as features. According to the results of regression analysis, there was no significant relationship between spectral indices and salinity values in all soil horizons. The obtained correlation coefficients were lower than 0.5 and, therefore, the relationship was very low.

Keywords: soil salinization, irrigation system, interpolation method, soil mapping.

Financing. The work was carried out on the topics of state tasks No. 0591-2019-0023 «To study the influence of natural conditions and land use features on the soil cover, including with the participation of saline saline and slitized soils and to develop a technology for assessing the intensity of exploitation of agricultural land soils» and No. AAAAA-A19-119012390065-9 «Development of methods for analysis and integrated use of remote sensing data based on modern geoinformation technologies for monitoring natural landscapes of agricultural lands using groups of small spacecrafts».

Acknowledgement. The authors express their gratitude to the employees of the Volgograd Hydrogeological and Reclamation Party for the data provided for the work.

DOI: 10.24412/1993-3916-2022-2-102-112

INFLUENCE OF SLOPE EXPOSURE ON CHEMICAL AND BIOLOGICAL PROPERTIES OF SOILS OF AGRICULTURAL TERRACES OF DAGESTAN

Arid Ecosystems

UDC 631.46:631.48:930

Pinskoy V.N.,  Idrisov I.A.,  Kashirskaya N.N.,  Yeltsov M.V., Potapova A.V.,  Borisov A.V. INFLUENCE OF SLOPE EXPOSURE ON CHEMICAL AND BIOLOGICAL PROPERTIES OF SOILS OF AGRICULTURAL TERRACES OF DAGESTAN // Arid ecosystems. 2022. V.28. № 2 (91). P. 113-121 . | PDF

The study of the dependence of chemical and microbiological properties of soils of agricultural terraces of the middle mountain zone of the Eastern Caucasus formed on limestone and shale, on the exposure of the slope is presented in the article. It is established that the slope exposure significantly affects the properties of soils of the same type of soil-forming rocks. The formation of terraces with an arable surface close to horizontal changes the angle of incidence of sunlight, which leads to an increase in the heat supply of soils on the slopes of the northern exposure and a decrease on the southern slopes. As a result of the change in the thermal regime, in the upper horizon of terraced soils, the differences in chemical and microbiological properties on the slopes of the northern and southern exposures decreased, compared with the differences in the background soils that were not subjected to terracing. The leveling effect of terracing was more pronounced on gentle slopes of 5-15°, with the greatest width of the terraced canvas, compared with the soils of narrow terraces formed on steep slopes.

Keywords: Eastern Caucasus, agricultural terraces, slope exposure, chemical composition, biological activity.

Financing. Chemical and microbiological analyses were carried out with the financial support of the RFBR grant «Anthropogenic soils of agricultural terraces of the Caucasus» No. 19-29-05205, 2019. Field work in 2019 was carried out within the framework of State Task No. 0191-2019-0046.

DOI: 10.24412/1993-3916-2022-2-113-121

INFLUENCE OF TECHNOPEDOGENESIS ON THE MORPHOLOGICAL AND CHEMICAL PROPERTIES OF SOILS IN RECREATIONAL AREAS (BY THE EXAMPLE OF SASHA FILIPPOV PARK)

Arid Ecosystems

UDC 631.41

Gordienko O.A. INFLUENCE OF TECHNOPEDOGENESIS ON THE MORPHOLOGICAL AND CHEMICAL PROPERTIES OF SOILS IN RECREATIONAL AREAS (BY THE EXAMPLE OF SASHA FILIPPOV PARK)  // Arid ecosystems. 2022. V.28. № 2 (91). P. 122-131 . | PDF

Soils of recreational areas of urban landscapes of Volgograd on the example of the Sasha Filippov park were studied. The soil cover of the park is represented mainly by typical (Urbic Technosol), replanted (Urbic Technosol (Mollic)), technogenic (Urbic Technosols (Hyperartefactic)) urbostratosems, replantazems (Phaeozem (Prototechnic)), and urbostratosems on buried chestnut soils. Under buildings and road pavements, screened urbostratosems (Ekranic Technosols). The presence of buried horizons suggests that the original soil cover in this area was represented by chestnut soils (Haplic Kastanozems (Loamic)). The average thickness of urbic horizons (UR) is 95 cm, reclamation layers (RAT) – 50 cm. The soils of the square vary in their chemical and physical properties.  The content of soil carbon in the urban and reclamated horizons varies from 0.11 to 2.46%. Chemical analysis of the urban (UR) and reclaimed (RAT) horizons revealed a low content of readily soluble salts of 0.11% and carbonates of 1.1% and 1%, respectively. In the RAT and UR layers and anthropogenic horizons, the density values averaged 1.43-1.46 g/cm3. The density value of buried horizons averaged for BMK – 1.58 g/cm3, B – 1.62 g/cm3, BCA – 1.53 g/cm3, which is higher than the average density values for native chestnut soils.  In the carbonate soil-forming rock Cca this indicator averaged 1.38 g/cm3. The obtained results allow us to study in more details the peculiarities of soil genesis in urban recreational areas and anthropogenic transformation of natural chestnut soils in the conditions of the dry-steppe natural zone.

Keywords: recreational areas, soil classification, urban soils, urbostratozems, replantzemes, physical properties of soils, chemical properties of soils.

Financing. The work was carried out with the financial support of the Russian Foundation for Basic Research within the framework of the scientific project No. 20-34-90129 «Soils of recreational territories of Volgograd: diversity, properties, ecological functions».

DOI: 10.24412/1993-3916-2022-2-122-131