Thickness Of Humus Horizon Research Articles

Analysis of organic matter stock dynamics in arable soils of Yamal: simulation experiments with the ROMUL model

The goal of this work is to analyze the dynamics of soil organic matter (SOM) in arable soils of Yamal using computational experiments with the ROMUL model. Soil temperature and moisture dynamics were simulated using the SCLISS model. The Yamal experimental station was organized in 1932. The soil is Plaggic Podzol. The thickness of humus horizon (PY) is 30 cm. Pools, kg/m2: SOM – 9.32 and 13.75; N – 0.46 and 0.66 for 0–20 and 0–30 cm respectively. Background: soddy-green-moss tundra near Salekhard. Soil: Folic Podzol: litter (O, 2 cm) and humus-accumulative (AY, 4 cm) and illuvial ferruginous (BF, 6 cm) horizons. Pools, kg/m2: SOM – 1.38 and 2.69, N – 0.03 and 0.18 for 0–2 and 2–6 cm respectively. The quantity and quality of background fall was estimated according to literature data. Clarification of the amount of fall was carried out by the method of inverse problem solving (spin-up). Peat application was simulated: starting application in the dose of 12 kg/m2 and maintenance (every 6 years) in doses 4, 8 and 12 kg/m2, N 1%. Application of mineral fertilizers, 2 variants: a) N 4 g/m2 (40 kg/ha) in peatting years and b) application of the same dose of nitrogen every year. The duration of computational experiments is 30 and 90 years. Computational experiments showed that after the starting peatting of Folic Podzol at the rate of 12 kg/m2 after 30 years, only 15% of the applied detritus remained. Maintenance peatting of 8–12 kg/m2 leads to an increase in SOM pool to 20–30 kg/m2 and excessive accumulation of detritus. Application of 4 kg/m2 of peat once every 6 years for 90 years shows the dynamics of SOM pools from Folic Podzol to Plaggic Podzol which is confirmed by field survey data. Application of mineral nitrogen (4 g/m2) once every 6 years does not affect SOM pools. Annual application of mineral N (4 g/m2) increases SOM pools due to intensified humification. This fact requires experimental verification.

Study on the Factors Affecting the Humus Horizon Thickness in the Black Soil Region of Liaoning Province, China

Understanding the spatial variability and driving mechanisms of humus horizon thickness (HHT) degradation is crucial for effective soil degradation prevention in black soil regions. The study compared ordinary kriging interpolation (OK), inverse distance weighted interpolation (IDW), and regression kriging interpolation (RK) using mean error (ME), mean absolute error (MAE), root mean square error (RMSE), and relative RMSE to select the most accurate model. Environmental variables were then integrated to predict HHT characteristics. Results indicate that: (1) RK was superior to OK and IDW in characterizing HHT with the smallest ME (11.45), RMSE (14.98), MAE (11.45), and RRMSE (0.44). (2) The average annual temperature (0.29), precipitation (0.27), and digital elevation model (DEM) (0.21) were the primary factors influencing the spatial variability of HHT. (3) The HHT exhibited notable variability, with an increasing trend from the southeast towards the central and northern directions, being the thinnest in the southeast. It was thicker in the northeast and southwest regions, thicker but less dense along the southern Bohai coast, thicker yet sporadically distributed in the northwest (especially Chaoyang and Fuxin), and thick with aggregated distribution over a smaller area in the northeastern direction (e.g., Tieling). These findings provide a scientific basis for accurate soil management in Liaoning Province.

Spatial distribution of soil depth in relation to slope as a consequence of erosion-accumulation processes in loess lowland hills of Slovakia

Abstract In our study, we examined the influence of slope gradient on erosion processes and present soil formation and change on loess hills. We analysed data from the two study areas and found that slope gradient is a significant factor influencing soil depth as well as humus horizon thickness. At the Báb locality, we observed a negative correlation between slope gradient and soil depth (r = –0.206, p < 0.05) and a negative correlation between slope gradient and humus horizon thickness (r = –0.227, p < 0.01). At the Nová Vieska locality, there was a negative correlation between slope gradient and soil depth (r = –0.334, p < 0.02), as well as between slope gradient and humus horizon thickness (r = –0.356, p < 0.01). These findings confirm that slope gradient is a key factor influencing soil formation in loess hills, and has a significant impact on its depth and soil profile. The analysis revealed that a critical slope of 3° significantly influences soil formation, with shallower soils and a thinner humus horizon occurring on steeper slopes. Our findings have important implications for planning erosion control measures and soil management depending on the location and slope gradient. Overall, our work provides insights into soil formation processes in loess hills and contributes to a better understanding of the interactions between slope gradient and erosive processes.

Influence of Morphometric Relief Parameters on Soil Depth Changes and Humus Horizon Thickness in Relation to Erosion-Accumulation Processes: A Study in the Ipeľská Pahorkatina Hills, Slovakia

Abstract This study examines the spatial distribution of soil types and their susceptibility to erosion and accumulation processes in a study area in Slovakia. Field research involving 71 probes identified various soil types, with Regosols and Cutanic Luvisols being predominant. The study found that erosion-accumulation processes were detected in 69.97% of the probes, with changes observed in soil horizons. Soil analysis revealed different relations between soil depth, humus thickness, and terrain characteristics such as slope, slope length, and slope length and steepness factor (LS factor). Specifically, we confirmed a moderately strong positive correlation between soil depth and humus thickness (r = 0.597, n = 71, p < 0.001). Shallow soils (0–30 cm) exhibited a very strong positive correlation between soil depth and humus horizon thickness (r = 0.978, n = 33, p < 0.001). Conversely, no relationship was found in moderately deep soils (30–60 cm) (r = 0.018, n = 14, p < 0.948). For deep soils, we identified a moderately strong positive correlation (r = 0.345, n = 24, p = 0.098). While slope and slope length showed relationships with soil depth and humus thickness, the LS factor did not exhibit a clear correlation. These findings underscore the importance of understanding soil dynamics in informing land management practices, especially in areas susceptible to erosion. Recommendations include continued monitoring of eroded soils and implementing erosion control measures to maintain soil health and sustainability in agricultural production amidst climate change challenges.

Impact of the B-Plus white pearl (Belyi Zhemchug) preparation on the spring frost tolerance, yield and quality of apple crops

In 2021–2022, experiments were conducted at the Laboratory of Fruit Crop Resistance Physiology, All-Russia Institute for Fruit Crops Breeding (VNIISPK), to investigate the action of the “White Pearl Antifreeze” (Belyi Zhemchug Antifriz) phytomodulator and the “White Pearl Drip Ca + Mg” (Belyi Zhemchug Drip Ca+Mg) phytocorrector produced by the AgroPlus Group of Companies, LLC. Experimental and control plots were characterized by dark-gray forest soils with a humus content of 3-4 % and a humus horizon thickness of 30–35 cm. Apple trees cv. Sinap Orlovsky (VNIISPK) grafted on semi-dwarf rootstock 54-118 were planted in 2013 according to a 6 x 3 m scheme. Natural grassing was used in row spacings; herbicides were applied around the seedlings. The experimental design included: 1) control (water treatment) and 2) foliar treatment with a 1 % solution of “White Pearl Antifreeze” + a 1 % solution of “White Pearl Drip Ca+Mg”. The experiment was conducted in three replications with five observed trees in each. Our aim was to assess the effect of the mentioned preparations on the spring frost tolerance, yield, and quality of apple fruit under the weather conditions of 2021. Foliar treatments with the studied preparations reduced the frost damage to Sinap Orlovsky apple buds by 6.3 % at -3.5 °С and by 10.4 % at -4 °С. The conducted summer foliar treatments with the organomineral mixture under study intensified the growth and ripening of apple fruit. The improved protein-carbohydrate metabolism, water regime, photosynthetic activity, and donor-acceptor leaf–fruit relations increased the fruit weight by 10 g and the yield by 1.8 times. The conclusion is made that the B-PLUS “White Pearl Antifreeze” preparation exhibits a complex effect in terms of increasing plant tolerance to low-temperature spring damage, thus improving the yield and quality of apple crops.

The influence of agroforestry on Chernozems: a case study of the Central Russian Upland

Agroforestry is an essential tool for improving soil fertility and sustainable land use. We aimed to reveal the role of the old-growth shelterbelt in changing the basic Chernozem properties under the shelterbelt and at 10, 30, and 60 m distance from its edges (the south of the Central Russian Upland, Belgorod region). Our database includes organic carbon content, storage, and group composition, total nitrogen, exchangeable magnesium and calcium, the soil - water extract composition, and pH from different soil layers up to 3m. We detected the increase in humus horizon thickness, soil organic carbon content and storage, total nitrogen, exchangeable magnesium, acidification, and lowering the effervescence line in shelterbelt soil in comparison to arable ones. Agroforestry leads to the soil transformation - the shelterbelt soils differ from arable at subtype taxonomic level, and the influence of shelterbelts on adjacent arable soils can be traced up to 60 meters distant.

Influence of different fertilization and chemical recruitment systems on the phosphorus regime of gray forest soil

Phosphorus is extremely important in agriculture. This is due to the fact that without its participation in the plant body does not undergo any biochemical reaction, because it is part of the ATP molecule, which provides energy. It is an essential element of nucleic acids, phospholipids and the others is actively involved in the regulation of enzymatic reactions. It is part of human, animal, plant and bacterial cells. The research was conducted on the basis of a stationary experiment conducted in 1992 on gray forest coarsegrained light loam soil, studied the effect of long-term chemical reclamation and various fertilization systems (mineral, organic, organic-mineral) on the transformation of Optimal phosphorus nutrition promotes the development of the root system, which improves the supply of plants with moisture and nutrients, increases the share of marketable products in the organic crop, increases the starch content in potatoes, sugar in roots, vegetables and fruits, oilseeds, oilseeds the output of a long fiber, its strength increases. That is why the management of phosphorus nutrition of plants is one of the key issues. Changes in various forms of phosphorus (gross, mobile, water-soluble) under the influence of the above factors are analyzed. For a more objective assessment of these factors on the phosphate regime of the soil on the variant results of the analysis were compared not only with absolute control, but also tied to baseline (age of fallow 28 years), located next to the experimental field. It was found that the content of gross phosphorus, which characterizes the genetic characteristics of the soil, depends almost entirely on the total humus reserves and clearly repeats the parameters of the profile accumulation of carbon, taking into account the depth and thickness of humus horizons. The particle size distribution is of great importance in the processes of gross phosphorus accumulation, as defects are quite easily adsorbed on the surface of soil structures. Evaluation of the results of the analysis shows a large gap in the gross forms of phosphorus and low concentration of its mobile forms, the content of which is 4.7% of the total. According to our data, water-soluble salts of phosphoric acid in gray forest soil are generally found in very small quantities (0.62 mg / kg in the horizon NOT with a gradual decline down the profile), which often becomes a limiting factor in phosphorus nutrition of crops. Lime, by reducing the activity of one and a half oxides, weakens the adsorption bonds of phosphorus and increases the relative amounts of calcium phosphates. The application of mineral fertilizers replenished the pool of gross phosphorus (by 0.08% of the control dock), but mobile forms of phosphorus (according to Kirsanov) increased by only 23 mg/kg, which was second only to liming. In general, the effect of liming significantly increases the use of soil phosphates and fertilizers.

AN ECOLOGICAL ASSESSMENT OF THE STATE OF SMALL RIVERS IN THE MIDDLE TAIGA SUBZONE OF KARELIA

A multidisciplinary survey of three small rivers emptying to Lake Onego was carried out; information was collected regarding the aquatic biota, the species and age structure of riparian forests, their floristic diversity, and soils. The integral indicator chosen to assess the ecological condition of the watercourses was the characteristics of the rivers’ fish fauna, in particular fish of the Salmonidae family. Surveys of the rivers and riparian forest communities yielded records of 181 vascular plant species (11 of them macrophytes), 11 moss species, 2 lichen species; the fish fauna was made up of 9 species. Overall, the riparian forests featured a relatively wide range of typological diversity. The tree stands varied from the poor Ledum types (site class V) to the most productive Oxalis types (site classes III–I). Analysis of the tree species and age structure of forests in the riparian buffers revealed a prevalence of stable coniferous tree stands in good condition. Statistically reliable correlations were detected between the fish fauna and the tree species composition and inventory characteristics of the riparian forest stands, soil morphological characteristics, and the species diversity of the living ground cover and macrophytes. The species diversity of the riparian and the aquatic biotas were found to correlate positively with each other. Fish numbers were seen to negatively correlate with some characteristics of riparian forest soils (forest floor thickness, podzolic horizon), while the correlation with the humus horizon thickness was positive. Significant positive correlations were identified between aquatic organisms (fish, zoobenthos) and a majority of the stream’s hydrological parameters. The resultant up-to-date information about water-forest system components is important for understanding the role of small streams, which, alongside the scant officially recognized “spawning” rivers, are an ecological niche in the life cycle of salmonid fishes in Northwest Russia.

Assessment of the soil cover in the Irkutsk Region by cadastral value

The article defines the specific indicators of the soil cadastral value for the agroclimatic subzones of agricultural landscapes in the Irkutsk Region. We calculate the cost of the soils most common in the region, which are present in the scales of land classification and in the Unified State Register of Soil Resources of Russia. For the first time for the Irkutsk Region, we assess the quality of agricultural land rather by soil types, taking into account the area of a land plot, standard yield, and technological (standard) costs, than by soil differences. Soils in the land-assessment zones are represented according to the USSR soil classification system of 1977 and the international WRB system. Average values of the specific indicator of the cadastral cost of lands are within 0.1 RUB/m2 in typical sod podzolic soils (Albic Folic Luvisols (Cutanic, Different)); they reach 0.3 rubles/m2 in sod alluvial saturated layered soils (Mollic Fluvisols (Orthofluvic Amphifluvic)) and 3.1 rubles/km2 in leached chernozems (Umbric Calcic Luvic Phaeozems) as well as 3.3 rubles/m2 in meadow chernozems (Chernic Phaeozems (Endocalcic)) and in sod alluvial saturated soils (Mollic Fluvisols). Low indicators of the cadastral cost of agricultural land are due to low values of agroclimatic potential, low humus content in these soils and low thickness of humus horizon. We indicate the sensitivity of the method for calculating the cadastral cost of lands (2017) to different soils and geographical conditions.

Study of thickness of humus profiles of gray forest and chernozem soils of different terms of agricultural use in landscape shrubs of the central forest-steppe

The article presents the results of a field study of the thickness of the humus profiles of gray forest soils and podzolized chernozems of dif-ferent terms of agricultural use of soil catens of broad-leaved-forest (background) and meadow-steppe areas of the Belgorod region. The work was carried out in the spring and summer period 2018-2019. The objects of the study were different-aged arable plots with the age of agricultural development of 100 and 160 years, respectively. The steepness of the surface on the plots did not exceed 5-60. It is established that the thickness of humus profile under the influence of agricultural cultivation during 60 years has decreased by 49 cm, at that on the slopes of northern exposition this index is more expressed (33 cm) than on the slopes of southern exposition (16 cm). It is possible, to note, that with increase of age of agricultural use on slopes of northern and southern expositions the greatest thickness of humus horizon is observed on anomalous soils (72 and 65 sm accordingly). Within the background catens the soil cover is homogeneous, the second humus horizon was observed in each of the studied transects.

Syntaxonomy and ecological differentiation of the pioneer vegetation of Ukraine. 2. Helichryso-Crucianelletea maritimae, Festucetea vaginatae, Koelerio-Corynephoretea canescentis classes

Pioneer psammophytic vegetation is usually developed on wind-drift sandy substrates such as arenas, spits, beaches, river terraces, and this vegetation occupies significant areas in all three natural zones of Ukraine. The Koelerio-Corynephoretea canescentis class was represented by 13 associations, 3 alliances and 1 order; Festucetea vaginatae class by 22 associations, 2 alliances and 1 order; Helichryso-Crucianelletea maritimae by 10 associations, 4 alliances and 1 order. The results of cluster analysis and synoptic tables of the classes are presented. 9 alliances are briefly described. Leading factors of territorial and ecological differentiation are identified. It was found that the territorial distribution of plant communities is influenced by the character of ecotope mesorelief, soil composition and humus horizon thickness, as well as the degree of eolian processes development. The main factors of their ecological differentiation are soil acidity, salt regime and ombroregime. Based on the results of DCA-ordination of syntaxa within certain vegetation classes, it was found that their distribution is influenced by factors that correlate with the environment-specific conditions. It has emerged that an ecological differentiation of syntaxa within Festucetea vaginatae is determined by the integrated effect of gradients, and soil salinity is leading among them. Temperature regime and climate continentality are leading factors in the distribution of syntaxa within the Koelerio-Corynephoretea canescentis class. The gradients of ombroregime and soil humidity have a significant impact. The distribution of communities of the Helichryso-Crucianelletea maritimae class in the ecological space is determined mainly by factors of variability of damping, ombroregime and climate continentality. The author’s syntaxonomic concept assumes the independence of the studied classes: Koelerio-Corynephoretea canescentis, Helichryso-Crucianelletea maritimae and Festucetea vaginatae, conside­ring that the leading factors of community differentiation of the Festucetea vaginatae and Koelerio-Corynephoretea canescentis classes are the origin (genesis) of sandy substrates, as well as soil acidity. Phytosociological analysis of a large number of relevés of coastal littoral vegetation also provides support for independence of the Helichryso-Crucianelletea maritimae and Ammophiletea classes diffe­rent floristically and ecologically. A review of the psammophytic vegetation of Ukraine will determine the place of the selected syntaxonomic units in the pan-European system.

Influence of agricultural technologies on the morphological properties of chernozems

A comparative assessment of the morphological properties of typical and ordinary chernozems using traditional technology of field crops cultivation with soil treatment and no-till revealed trends in morphological properties changing over time and space. After using no-till on typical chernozems of the Kursk region for 4 years, there was a tendency to increase in humus horizons A and A + AB thickness and in the level of carbonate detection line (10% HCl reaction), which uprose closer to the soil surface. In ordinary chernozems of Stavropol after 7 years of using no-till, this trend is typical only of A + AB horizon. When plowing chernozems, there is a trend to deeper carbonate accumulation level. The gradual accumulation and decomposition of crop residues on the soil surface, which play an important role in wind erosion protection, and less intensive evaporation over time leads to an increase in the thickness of humus horizons and the content of organic matter. The results obtained are indicative of the initialization of morphological properties transformation in chernozems when no-till is used. The decrease in the thickness of the humus horizon on arable lands in Stavropol region results from deflation caused by both numerous soil treatments and a specific wind regime, and direct sowing has demonstrated positive results in the fight against wind erosion processes. When no-till technology is used, chernozems acquire natural features typical of them – variability of properties, i. e. the initial heterogeneity of soil cover, which determines the sustainability of soils in natural ecosystem.

Agroecological substantiation of the sustainable development of arable soil fertility of the Altai dry steppe

The soil resources of the Altai dry steppe (and their fertility in particular) degrade in their evolutionary anthropogenic development. Transformation of fertility is occurring due to a combination of phenomena, such as natural conditions, intensive use, farming system practiced in the absence of science-based regimes. It is established that the humus content and humus horizon thickness are statistically significantly reduced due to the activation of deflation and dehumification processes. More than that, areas of alkaline soils are increasing. The authors also point out to the degrading granulometric composition. Also, the amount of physical clay, silt fractions, cation exchange capacity, exchangeable calcium, potassium, and mobile phosphorus decreases. Statistical processing of fertility parameters of allowed us to develop a scale of process dynamism and establish the degree of dynamism in the considered soil properties, as well as to assess the rate of increasing adverse changes or their absence. Intensity of degradation processes and indicators determining it contributed to the development of levels of agro-ecological state, such as “Norma”, “Risk”, “Krizis” and “Bedstviye” (based on GIS).

Maximum Humus Horizon Thickness as a Criterion for Identifying Standard Soils in the Crimean Plain

Abstract—The identification of the main soil categories in the structure of the regional Red Book should focus on typical soils that were formed taking into account the zonal soil-ecological conditions of the territory. The initial, preagrogenic thickness of the humus horizon that fully implements the soil-forming potential of natural factors of full-profile climax soils can serve as a criterion for identifying standard soils. However, the search for these sites has some methodological difficulties. The proposed mathematical modeling for processes of the soil humus horizon’s formation makes it possible to quantify the legitimacy in the identification of standard soils. This method allows using cartographic models for determining the maximum thickness of the humus horizon. Analysis of the presented material suggests that the profiles of most agricultural lands are currently 30% destroyed in Crimea compared to the estimated maximum thickness of the humus horizon, which predetermines the search for standard soils only in areas that were not previously exposed to agrogenic conditions (most often, in specially protected natural areas), taking into account the features of the zonal process of soil formation.

Maximum humus horizon thickness as a criterion for identifying the soil standards of the plain Сrimea

When identifying the main categories of soil in the structure of the regional Red Book of soils, it is necessary to focus on typical soils formed taking into account the zonal soil-ecological conditions of the territory. The criterion for the extraction of soil standards can be the initial, pre-agrogenic thickness of the humus horizon, which fully realizes the soil-forming potential of natural factors of climax full-profile soils. But the search for such sites is associated with a number of methodological difficulties. A way out of this situation can be a mathematical modeling of the formation of the humus horizon of soils, which allows you to quantify the legitimacy of the allocation of soil standards in the structure of the Red Book of soils of the Crimea. The proposed method allows going to the cartographic models for determining the maximum thickness of the humus horizon. Analysis of the presented material allows asserting that in the majority of modern soils of agricultural lands of the Crimea, the profiles are destroyed by 30% compared with the calculated maximum thickness of the humus horizon, which takes into account the zonal soil formation processes. That predetermines the search for soil standards only in areas that did not function previously in agrogenic conditions, most often, these are protected areas that take into account the peculiarities of the zonal process of soil formation.

Assessing soil redistribution in sinkholes using fly ash fallout: a case study in the Perm Region, Russia

The assessment of soil matter lateral transport in five different sinkholes is the focus of this study. Fly ash (the particular component of the smoke produced by steam locomotive) was used to assess the erosion amount and rate. The objectives include to calculate the erosion, transport and deposition rates on the side slopes of sinkholes, to assess the amount of soil matter loss from sinkholes to cavities, and to evaluate the relationship between the volume of the lateral soil matter transport and soil properties. The soils of the sinkholes are more exposed to erosion than to deposition, the accumulation of soil matter occurs only on the lower parts of the sinkhole side slopes and only the material of the humus horizon is involved in lateral transport. Over 20% of the soil matter involved in soil redistribution was lost from the sinkholes with ponor to underground cavities over the last 100 years. The mean erosion rate is 8 t ha− 1 year− 1 for loamy soils (45% slope inclination) and 13 t ha− 1 year− 1 for skeletic sandy loam soils (63% slope inclination). Soil matter movement plays a critical role in the formation of sinkhole soilscapes; it causes the increase of the humus horizon thickness and the decrease of the soil property variability from the top to the bottom of the sinkholes.

Typological Diversity of the Estonian Calcareous (Alvar) Forests

The calcareous forests in northern Europe are characterised by a very high species diversity including numerous red-listed species. The aims of the current study were: (i) to describe the Estonian calcareous forests' diversity both on the species and community levels, (ii) to identify the indicator/characteristic species of the established community types and, (iii) to identify the main environmental factors affecting these communities. Of the 271 recorded vascular plant species, 55 occurred in such forests within their geographical distribution limit or close to it. Regarding soil properties, the humus-horizon C content, CaCO3 content and loss on ignition (LOI) were found to affect the total number of species. All in all, 12 community types were established, each having their own dominating and statistically reliable indicator species. The community types also differed in their structure and characteristics of the soils (particularly humus horizon thickness and depth of the rubble layer). Although calcar...

Variation in main morphometric parameters of chernozems under anthropogenic impact

Data characterizing the distribution pattern of the main morphometric parameters of chernozems in the Kamennaya Steppe are given. Variable thickness of humus horizon within a flat test plot typical for the central part of the chernozemic zone of Russia is shown. It has been revealed that annually exerted strong anthropogenic impact causes a pronounced drop in the thickness of humus horizon. The investigated objects on the test plot—fallow land, plowed filed, and forest shelter belt—were situated side by side. The statistical parameters of the thickness of humus horizon in different subtypes of chernozems have been calculated. They mainly differ by the depth of continuous impregnation with calcium carbonate (effervescence depth varies from 1 to 95 cm). The deepest effervescence is seen in the soils of the fallow and under the forest belt (68 and 63 cm, respectively).

ESTIMATE OF CHERNOZEM ERODIBILITY LEVEL ACCORDING TO THE HUMIFICATION DEGREE

A short review of literature sources is presented to characterize the eroded soils according to their humus content. Traditional diagnostic indicators of the soil erodibility level based upon the humus status are the following: (1) decrease in the thickness of humus horizons in eroded soils in percentage of that in uneroded soil (standard); (2) decline in the humus storage in the eroded soil profile in percentage of that in uneroded soil (standard). It is worth emphasizing that the choice of the uneroded soil standard is a rather labor-consuming study in field and assumes an expert (subjective) character that is highly dependent on the soil scientist’s skill. It is shown that the main shortcomings of the available gradation for eroded soils consist in the absence of approaches to give their objective estimate and recommendations for permissible levels of soil erodibility taking into complete account the humus content in these soils. In the Russian Federation there is a gradation of arable soils (including chernozems) according to the humus content in the plough horizon. It contains four classes (less than the humus minimum, low, moderate and high humus content). In this paper it is recommended to give the gradation of eroded soils with the minimal humus content. The level of chernozem erodibility should be estimated as based upon the minimal and critical humus content. The minimal humus content is interpreted by Kërshens, whereas the critical humus content - by Kiryushin and Ganzhara. A gradation scale of soil erodibility is presented to estimate its permissible, non-permissible and critical levels. It is exemplified by the gradation of chernozem soils in Russia and Germany.

Аналіз морфометричних особливостей профілів ґрунтів для оцінки їхньої еволюції

We studied the soil of different ages of chronological catenas at stationary Precarpathian and PrutDniester interfluvial. The obtained results of the morphometric features of the background and buried soils extend the capabilities for the interpretation of their evolution. Thus more soundly use of absolute values of morphometric parameters of genetic soil horizons. We showed, that the thickness of humus horizons and first of all the background soil profile generally, during the time after burial of soil increased. This is due to an increase in humidity of the climate in the last 1000 years. Key words: soil: background and buried, genetic horizon, thickness, the ratio between the horizons.