No 10 (2023)

The present study investigates morphological, physical and chemical properties of Chernozems at dense parent rocks. The research was carried out on the protected areas native soils of the north-west of the Rostov region. This territory is representing eastern slopes of the Donetsk Ridge, which predetermines the dense rocks release to the surface. It has been found that morphological, physical and chemical properties of Chernozems on dense rocks have emphasized their originality and uniqueness, and at the same time clearly have indicate their classification as Chernozem order. In comparison with the zonal soil – Calcic Chernozem – Chernozems on dense rocks are characterized by a reduced thickness of humus-accumulative layers, an increased of humus content, the presence of gravel in profile bottom half, a weak expression of calcareous accumulations, features of the particle-size distribution of soil components, even if it belongs to the same soil texture class. Chernozems on dense carbonate rocks either do not have accumulation or are characterized by a weak manifestation of secondary carbonates (pseudomycelia and nodules). This fact has differed such soil from the same order Chrernozems on fine-grained rocks (Calcic Chernozems) for which it is diagnostic criteria. Therefore, the mention of the suborder of these soils is incorrect in the designation. In the soil covering of the spurs of the Donetsk Ridge, dark humus soils are also occure, previously classified as incomplete developed chernozems, differing from chernozems by the absence of medium part of soil profiles.

The sorption of phosphorus by salt marshes of the dry-steppe zone of the Republic of Buryatia from an aqueous solution of KN₂PO₄ in the concentration range from 0.25 to 5.0 mM/L (mmol/L) was studied under static conditions. The interaction time is 24 hours with a soil: solution ratio of 1 : 10. The amount of sorbed phosphorus was calculated from the difference in its content in the initial solutions and in the filtrates of soil suspensions. Based on experimental data, phosphorus adsorption isotherms were constructed by soil and sorption parameters were calculated using the Langmuir and Freundlich equations. Typical and quasi-clay Solonchaks have relatively high sorption properties with respect to phosphorus. The value of the maximum adsorption capacity (Amax) in the humus horizons of these soils varied in the range of 23.04–42.74 mM P/kg, in the underlying horizons 16.26–30.39 mM P/kg. In general, all soils, with the exception of the sorov Solonchaks, had an Amax value in the range of 17.70–42.74 mM P/kg. A low sorption value of phosphorus was found in the Solonchaks of sorovy. The Langmuir adsorption constant (K_L) varied in the range of 0.3–14.0 l/mmol. Solonchaks dark and typical most strongly bind phosphorus. The Freundlich coefficient (K_F) in the studied soils varied in the humus horizon from 5.34 to 63.43 mM P/kg, in mineral from 1.74 to 22.68 mM P/kg. The distribution coefficient (Kd) ranged from 1.95–145.04 l/kg with high values for quasi-clay Solonchaks and low for sorov Solonchaks. The correlation between Kd and Amax was estimated as average (r = 0.51), Kd and K_L – high (r = 0.84, p ≤ 0.05). The studied soils according to the values of SPR (the amount of phosphorus that must be sorbed by the soil to maintain a concentration of P = 0.2 mg/kg (0.0065 mM/l) in soil solution) from (0.0723 to 3.4836 mM/kg) refer to weakly absorbing phosphorus. According to the ability to sorb phosphorus, soils form the following decreasing series: quasi-glay solonchaks > typical solonchaks > dark solonchaks > glay solonchaks >alluvial light humus saline > sorov solonchaks.

The results of approbation of new approaches to monitoring and forecasting of soil salinity of irrigated soils, based on indirect detection of soil salinity using multi-year archives of satellite data, are presented. Research was carried out on example of irrigated lands of Maktaaral district of Turkestan region of the Republic of Kazakhstan. As an indicator of soil salinity level frequency and terms of soil leaching from salts are used, which are identified on the basis of multi-year archives of satellite data Sentinel-1,2 and Landsat-8 (from 2016 to 2022). Information about the frequency of soil leaching from salts and the year of the last leaching allowed ranking the fields by the degree of soil salinity. Comparison of the obtained information with the fine-scale soil map and with statistical data based on field surveys of the fields showed a good level of similarity of the soil salinity level of the test region. A similar approach can be used for other regions with irrigated soils subjected to secondary salinization. It does not require additional adaptation and is based on simple algorithms of recognition from satellite data of water surface.

The article presents a new scheme of zoning of modern gully erosion in a large region of the Russian Federation. Automated landscape zoning by means of artificial neural networks was carried out in order to determine the natural and anthropogenic conditions for the development of the gully network. Erosion zoning was implemented on the basis of large-scale geoinformation mapping of gullies by the method of visual interpretation of high- and ultra-high-resolution satellite images for 2017–2021. The basins of small rivers (1314 in total) with an average area of 91 km² are taken as operational-territorial units. 22688 gullies (including their holes) were identified in the study area, the average length of which is 65 m, and the total length of the gully network is about 1500 km. The density of the gully network averages 12 m/km², reaching a maximum of 301 m/km². The density of gully dissection is used as an indicator for the zoning of gully erosion, this indicator indirectly reflects the intensity of gully formation in geo-space. The dominant (84% of basins) are areas either with no gully dissection or having weak or very weak gully erosion. The main reasons for the widespread damping of gully erosion are related to changes in land use and in the climate system, as well as an evolutionary factor – the transition of many gully forms to the balka stage of development.