The approaches to the definition of soil degradation were analyzed in the article. It was found, that there are five types of degradation of cultivated soils in Belarus, in each of which, there are from four up to six kinds. The authors developed qualitative and quantitative assessment of soil degradation, reflecting the loss levels of their natural and economic values.

The authors of the article the identified the methodological approaches to land typification illustrated by an example of specific land users with a high proportion of eroded arable soils of the Central soil and ecological province (Belarusian ridge). In the process of its implementation there were allocated 15 types of agricultural lands, given their detailed characteristic with the determination of quantitative indicators of heterogeneity of soil cover.

The article presents the results of development and filling in the ecological passport of soil as the information basis for the special protection of natural soils. The structure of an electronic database for filling in data fields of soil passports was illustrated. The authors present an example of filling in the passport for the typical sod-podzolic soil developing on fluvioglacial sands, succeeded by sandy loam soils, located on lands of the reserve «Ozery» of the Grodno region.

The article presents the results of studies of the effect of mineral fertilizers on yield of winter wheat cultivated on typical сhernozemic soils of forest steppe in Ukraine. A scheme of a field experiment was mathematically planned, that made it possible to process the data with modern statistical methods by a computer program. The optimum rate of fertilizer for winter wheat was the following: nitrogen - 65 kg/ha, phosphorus - 120 kg/ha P₂O₅. The authors developed a mathematical model of winter wheat yield forecasting for the typical сhernozemic soils of forest steppe in Ukraine. The main indicator of the mathematical model is an absolute term, which is equal to 65 kg/ha. Effect of factors (N, P, K) and their interaction increases the yield by 3.16 с/ha. The optimum rates of fertilizers for maximum yield, maximum profit, cost of power consumption and integrated indicator are determined.

Summary. The authors propose a methodological approach to the study of soil heterogeneity which is based on multispectral satellite scanning data. Multi-spectral data from the Sich-2 satellite are used for mapping and parametric description of chernozemic soils in the Northern Steppe of Ukraine: 1) to delineate soil mapping units and evaluate their spatial structure; 2) to quantitatively assess specific properties of eroded soils using geo-statistics and multi-dimensional data processing. Field description of soil profiles from the mapped soil classes demonstrated the efficacy of K-means cluster analysis for determining different elements of the soil cover. Maps of humus content, created by statistical and mathematical modelling, enabled to realize parameterization of chernozemic soils and further detailed analysis of the structure of humus scalar field.

An optimum fertilizing system of summer barley from the agronomical and economic point of view is determined. The system was characterized for different studied organic backgrounds: N₉₀₊₃₀P₁₅K₃₀ for the background without manure and for the background with 50 t/ha of manure aftereffect; N₉₀₊₃₀ - for the background with aftereffect of 100 t/he of organic fertilizers. The authors revealed the influence of the increased doses of nitric fertilizers (N₉₀₊₃₀) for the all studied backgrounds on grain production with high quality indicators.

On the basis of route studies and generalization of results of field experiments, the conversion coefficients of grain and seed in by-products were adjusted. The authors defined the change limits and the average content of nutrients in by-products of the same species for agricultural crops cultivated on the territory of the Republic of Belarus. With one ton of by-products the soil gets 3,8-9,9 kg of nitrogen, 1,8-5,2 kg of phosphorus, 11,7-28,0 kg of potassium, 1,4-10,3 kg of calcium, 0,8-6,1 kg of magnesium and 735-801 kg of organic matter.

On the basis of route studies of agricultural land the authors defined the availability of mobile cobalt in the main types of soils in Belarus. It was established that cobalt content in soils and crop products was low. It was specified by species related traits of agricultural crops and soil granulometric composition. In a field experiment, the authors determined the efficiency of foliar fertilization of blue lupine, winter wheat, spring barley and alfalfa with cobalt, depending on the level of its availability in sod-podzolic sandy loam soil.

Based on the research findings it was established, that higher efficiency (yield increase of flax seeds by 4,5 c/ha with profitability of 202 and 217 %) was provided by foliar application of microfertilizers MikroSil-Boron, Copper in a dose of 0.075 kg/ha a.s and MikroSil-Boron in a dose of 0.10 kg/ha a.s.

In the conditions of a glasshouse experiment, the authors revealed some regularities of trace elements uptake by plants of pea, barley, buckwheat and corn from soils with different basic indicators. A close correlation relationship between the trace elements uptake by plants and the content of their mobile forms in soil, soil texture and pH was determined.

On peaty gley soil the authors studied the effect of increasing rates of potassium fertilizers and soil provision with mobile potassium on entry of¹³⁷Cs into grain of spring wheat and hay of perennial grasses. It was established that between the content of mobile potassium in soil and the entry of¹³⁷Cs into products there was a strong inverse relationship (R² = 0,55). The most significant decrease in the transfer factor of¹³⁷Cs into plants was observed in case of increasing soil provision with K₂O in the range of 200-700 mg/kg. On condition of content of P₂O₅ 737-748 mg/kg and K₂O 625-665 mg/kg in soil, the most effective under spring wheat was the use of phosphate and potash fertilizers in R₆₀K₁₂₀ rates, reducing¹³⁷Cs grain intake by an average of 24 %. During cultivation of perennial grasses the maximum reduction of¹³⁷Cs in hay (2.2-3.0 times) was provided by the use of phosphate fertilizers in rates of P₆₀ and potash fertilizers in rates of K₂₄₀. On peaty gley soil, in contrast to the peat-bog soil, the¹³⁷Cs transfer factor into grain of spring wheat was 5 times below the average one; into hay of perennial grasses it was 2 times lower. In addition, in comparison with sod-podzolic sandy loam soil, the parameters of¹³⁷Cs migration into grain of spring wheat were 2 times higher, into hay of perennial grasses the parameters showed similar values.

In the conditions of a field experiment on highly cultivated sod-podzolic light loamy soil the authors determined biochemical indexes of humification activity in the main processes of aromatics oxidative polymerization. It was realized resulting from atmospheric oxygen (polyphenol oxidase) and peroxide oxygen (peroxidase) depending on the level of mineral nutrition of agricultural crops.

The research was conducted at the Biotechnology Department of the RUE «Institute for Fruit Growing» and the Institute of Physical Organic Chemistry of the National Academy of Sciences of Belarus. The chemical composition of the nutrient medium for Aronia melanocarpa Elliot plants cultivation in vitro on micropropagation and root formation stages was determined with the use of ion chromatography and atomic emission spectroscopy. Nutrient intake structure was established, ion usage difference at the various stages of in vitro growing is shown. The authors have established the significant change of ions starting ratio, increasing concentration of individual ions in the nutrient medium by the end of the cultivation, due to their uneven consumption by the plants.

A review of quantitative and qualitative criteria of physical degradation of arable lands was carried on the basis of own research and literature data about the physical degradation of arable soils. A definition physical degradation was given. The reasons of its occurrence and development were considered. The soil areas of predisposition to the physical degradation were determined. On these areas, where loss of agronomically valuable structure, manifestation of increased cloddy, dissipation and repacking, the application of effective prophylactic measures was justified. Based on the analysis of state of research of physical degradation of arable soils, the urgent problems in Ukraine were indicated. The most pending tasks are the regionalization of information about physical degradation of arable soils, determination of normative parameters of destroying and repacking and development of proposals on implementation of non-degradation agriculture.