The paper presents original developments on the application of WaTEM/SEDEM erosion model for large-scale mapping of erosion patterns of the soil cover in the Central Russian Upland. The share of eroded soils in the composition of soil combinations on plowed slopes was evaluated; such estimation was carried out on the basis of a statistical comparison of the calculated rates of soil losses with the results of actual soil-morphological diagnostics of the degree of chernozems erosion. The obtained relations between share of eroded soils in soil cover patterns and modelled erosion rates were used for development of the map depicting typified combinations of soils with various degrees of erosion. Comparison with detailed soil survey materials showed that the map is accurate enough for the spatial diversity and configuration of eroded soils combinations description. At the given input parameters of the erosion model qualitative changes in the soil cover structure (share of slightly-eroded soils is more than 10%) start from the threshold value of water erosion of 8 t·ha-1·year-1. With an average annual erosion of 30 t·ha-1·year-1, the share of denuded soils exceeds 50%. The developed approach seems to be promising for solving fundamental and applied problems related to the study of structural and functional organization of the soil cover of slopes and for planning the erosion control measures in adaptive-landscape agriculture.
The aim of the study was to research the relationship of chemical and micromorphological properties of soils with the growth of Kochia prostrata. The objects of study were the soils on natural pastures of the North-Western part of the Caspian lowland. It was laid 4 soil pits (soils – light solonetz, solonetzic chestnut) with the maximum penetration depth of the main mass of roots of the studied plants. K. prostratais a very plastic forage species that can grow on soils with a wide range of morphological properties, different salt content and their chemical composition. It is revealed that on the background of almost the same content of humus and high content of exchangeable magnesium micromorphological features represent the different degree of manifestation of primary pedogenic processes – humus accumulation, leaching of soluble salts, gypsum accumulation, carbonate enrichment, solonetzization. Despite the different content of exchangeable sodium, in all soils there are fresh clay or humus-clay illuvial coatings, indicating the manifestation of the modern eluvial-illuvial redistribution of fine matter (lessivage or illimerization).
The problems of radioactive contamination of biosphere with the 238U in recent years have attracted a large number of experts in various fields of knowledge. Natural radionuclides are an integral part of the biosphere. They are concentrated everywhere: in rocks, in soil, water, air and food. Various types of phosphorus fertilizers and other natural ameliorants used in agriculture are also an additional source of heavy natural radionuclides. The review describes the behaviour and migration of 238U in biosphere, which depend on various factors acting simultaneously. It is noted that the behaviour of 238U in the soil depends on the forms of its presence in it and the physical and chemical properties of the soil. The processes of sorption and desorption of 238U by different soil types are significant indicators.
Using the method of inoculation on elective nutrient media, the abundance and activity of taxonomic (bacteria, actinomycetes, micromycetes) and functional (nitrogen fixers, ammonifiers, denitrifiers of amylolytic, cellulolytic) groups of microorganisms in agrochernozems of the Stavropol region under the influence of various tillage systems – direct seeding (no-till) and moldboard plowing with the turnover of soil horizon (traditional treatment). Analyzes were carried out for such crops as winter wheat, corn, sunflower and soybean with/without application of mineral fertilizers. Traditional tillage for the majority of crops leads to increased activity of aerobic ammonifiers, cellulolytics, denitrifiers, actinomycetes and micromycetes. No-till technology, in its turn, increases the intensity of anaerobic cellulolytics and nitrogen fixers, aerobic diazotrophs and amylolytics activity. The most responsive crop, under which the biological activity of almost all groups of microorganisms increased in the no-till variant, was corn, while winter wheat contributed to the increase in the number of microorganisms in the moldboard plowing variant. The use of mineral fertilizers provoked the growth of soil biological activity under sunflower sown directly in the soil, while conventional tillage resulted in higher soil biological activity without application of mineral fertilizers.
ISSN 2312-4202 (Online)