The article briefly describes the methodology for assessing the fertility of soils in the second round of cadastral valuation of agricultural lands in Belarus. The characteristics of all factors taken into account in assessing land are given, their optimal parameters necessary for plant life and agricultural work are given. The influence of various factors on the assessment of soil fertility and the possibility of its increase by improving and bringing them to optimal parameters has been established. In total, due to the improvement of the cultural and meliorative condition of the working areas, the improvement of soil cultivation, the fertility of soils can be increased by 9,2 points, including 1,8-2,3 in the next 7-10 years.

The article presents the correlation of the Belarusian soil classification with the international WRB system. Announced the problem of correlation due to fundamental differences in the approach to the development of classification schemes. Emphasized the most striking deficiencies WRB system, which cast doubt on the practical significance of this classification.

The article presents а new interpretation of humus-granulometric interrelations of sod-pale-podzolic light loamy soils as a result of the cultural process of soil formation. The presence of a general principle of the relationship between the fractions of particle size distribution and the humus state, in particular, between the humus content in physical clay, the humus content in the soil and the grain size fractions through dynamic equilibrium constants is shown. The obtained data of humus-granulometric relationships can be applied as a new method to assess the degree of fertility and soil stability as a result of agrogenic effects.

The author developed a technique for mapping the quantitative content of humus from remote sensing data of the earth. In this work, the author used data from high-spatial resolution satellite resources and 3 test sites located in the Minsk and Baranovichi regions of the Republic of Belarus. Sod-podzolic soils of varying degrees of hydromorphicity and granulometric composition are characteristic of the studied areas. During the field work, 240 soil samples were selected and an analysis was carried out for the content of humus, according to Tyurin's method. Agrochemical soil analysis data were compared with data of optical brightness on cosmic images. As a result of the statistical analysis, high values of the determination coefficients for all the investigated fields were obtained, which makes it possible to use the spectral characteristics to obtain data on the intrinsic unevenness of the humus content.

Nitrogen of soil stocks prevails in nitrogen nutrition of grain crops. The yield of winter rye grain by 60-85 %, barley and spring wheat - by 66-75, legume-cereal mixture - by 88-92 % due to the nitrogen of the soil. With increasing rates of nitrogen fertilizers and their fractional introduction of their share in the formation of the crop increases. Of the forms of nitrogen fertilizers, the lowest specific gravity of nitrogen of fertilizers in its total removal was on automorphic soil in the variant with urea, the forms of introduced nitrogen did not differ on the gley soil. In the grain of winter rye on sod-podzolic light loamy soil, 75-78 % of the total nitrogen absorbed by plants of fertilizer was concentrated, on sandy soil - 68-70 %. Barley grain contains 80-84 % nitrogen of fertilizers from its total removal with the main and secondary products. With increasing rates of fertilizers and their fractional application, an increase in the accumulation of nitrogen in the grain is observed. The forms of nitrogen do not have a noticeable effect on the structure of its consumption by the base and by-products. More significantly affects the degree of hydromorphic soil. The utilization of nitrogen fertilizers on sod-podzolic soils varies from 20 to 62 % and depends on the level of soil fertility, cultivated crops, rates, timing of application and forms of nitrogen fertilizers. Fractional use of nitrogen contributes to an increase in its utilization rate, while a decrease in the rate of nitrogen fertilizers is observed to decrease.

The article presents experimental data on the agrochemical efficiency of nitrogen fertilizer UREA^STABIL (Czech company AGRA GROUP a.s.) for the cultivation of winter wheat on luvisol sandy loam soils in the central part of the Republic of Belarus for the period of 2013-2016. The effect of this fertilizer on the yield of the main and by-products, the protein content, gluten and the main nutrients in the wheat grain was presented as compared to carbamide standard.

The economic evaluation of the efficiency of mineral fertilizers at the cultivation of spring triticale on sod-podzolic light loamy soil (Podzoluvisol) with different content of exchangeable magnesium in the soil was carried out. It was found on control plots without fertilizers the yield increased on 35 % in the limits of Mg content 46-147 mg/kg of soil. Further increase of Mg content in soil up to 198 mg/kg was excessive; it followed by reduction of grain yield on 10 %. Maximal yield response to basic NPK treatment and response to foliar spray of Mg fertilizer was noted on low and medium content of exchangeable Mg 46-92 mg/kg in soil with total net return of 76 USD/ha. Efficiency of NPK and Mg fertilizers were strongly reduced on the plots with high level of soil Mg supply.

It was found in field experiments that the content of crude protein in the grain of spring triticale and its output per unit area had been increased with increasing of soil exchangeable magnesium supply up to 138-147 mg/kg of soil. The maximum value of the sum of critical and indispensable amino acids 7,02-7,17 and 24,0-25,31 mg/kg of grain, respectively, was obtained in fertilized trial with the equivalent ratio in the soil Ca:Mg cations around 5 and the ratio of K:Mg around 0,6.

On sod-podzolic light loamy soil the application N₉P₄₀K₆₀ and N₁₆P₆₀K₉₀ in top dressing in the spring and after the harvesting the cover crop (barley) was equivalent and increased the yield of green mass at the dose of N₉P₄₀K₆₀ 69 and 87 kg/ha and the dose of N₁₆P₆₀K₉₀ - on 171 and 181 kg/ha, respectively. The return of 1 kg of NPK kg of green mass of clover of application in the spring of N₁₆P₆₀K₉₀ was 103,0 kg and after harvesting the cover crope 109,0 kg. Non-root dressing in spring with boron and molybdenum on the background of N₁₆P₆₀K₉₀ to the increase in the yield of green clover mass by 60 c/ha (from 835 to 895 c/ha), the provision of feed unit with digestible protein by 9,9 g ( from 146 to 155,9 g). The use of N₁₆P₆₀K₉₀ in top dressing in the spring and after the harvesting the cover crop provided a higher net income (131,9 and 153,5 USD/ha) with a profitability of 44.6 and 51,3 %, respectively.

In the field experiments conducted on sod-podzolic loamy sand soil (Podzoluvisol) сlose negative correlations have been found between exchange calcium contents in the soil and⁹⁰Sr accumulation by plants. The efficiency of soil saturation by calcium in discrimination of⁹⁰Sr is much higher on soils with low Ca status. The minimum of bioavailability of⁹⁰Sr was observed at the content of exchange calcium for grain crops at 1300-1400 ppm of soil, rapeseed - 1195, corn - 1236, timothy grass - 980, clover - 1229, alfalfa - 1502 and potato - 1260 ppm of soil.

The сlose negative nonlinear correlations have been found between indexes of soil fertility and¹³⁷Cs accumulation by corn in field experiments conducted on sod-podzolic sandy soils. The minimum bioavailability of¹³⁷Cs for corn cultivated for green mass was observed at the organic matter content of 3.1 (2.8-3.5) %, mobile potassium - 436 (385-462) ppm, exchange magnesium - 244 (197-302) ppm and pH(KCl) - 6.3 (6.1-6.5). The effectiveness of soil saturation with organic matter, potassium and magnesium in¹³⁷Cs discrimination is much higher on soils with low supply of these nutrients for plants.

Depending on the meteorological conditions of the growing season, the transition of¹³⁷Cs to the hay of perennial grasses of the first cut changes up to 4.3 times, and to the hay of the second cut - up to 3.3 times. Such fluctuations in the content of radionuclides in products are largely due to the levels of the formed productivity of herbs. When cultivating perennial grass grasses on peaty gley soil with a P₂O₅ content of 876 mg/kg and K₂O 818 mg/kg, the maximum reduction of¹³⁷Cs content in hay of the first crop by 2,3 times provides 3,5 times in hay of the second cut phosphate fertilizers in a rate of P₉₀ and potash fertilizers in a rate of K₁₈₀ (K₁₂₀ for the first cut and K₆₀ for the second cut). Hay production of perennial cereal grasses, suitable for¹³⁷Cs content for obtaining whole milk, raw milk during processing for oil and meat, meets RDU, is possible without restrictions on the density of contamination of peaty-gley soil using phosphorus and potash fertilizers in rates of P₉₀K₁₂₀ (K₉₀ under the first cut and K₃₀ under the second cut).

The effect of MicroStim-Zinc on the yield and quality of maize for varying sufficiency of sod-podzolic sandy loam soil with this element was studied. It has been established that foliar application of corn with zinc fertilizer is effective only at low and medium levels of zinc soil availability. An increase in the accumulation of the element in the green mass and grain of maize was noted with an increase in its content in the soil and the introduction of microfertilizer MicroStim-Zinc into the foliar top-dressings.

The article presents the results of research on the effect of various types of microfertilizers ADOB on the yield and quality of winter wheat when cultivated on sod-podzolic highly cultivated light loamy soil. It was established that double foliar top dressing of winter wheat with ADOB microfertilizers contributes to an increase in grain yield by 3,2-5,4 q/ha, gluten content - by 0,6-2,9 %, crude protein content - by 0,7 %, yield crude protein - by 0,7 centners/ha with a profitability of 108,0-224,5 %

It was found that on highly fertile sod-podzolic loamy soil under organic farming system on the background of buckwheat straw plowing the yield of zucchini amounted to 88.3 t/ha. The significant yield increase compared to the background (24,3 t/ha, or 28 %) was obtained with the application of 40 t/ha cattle manure. Average yield of zucchini 112,5 t/ha ensured the lowest losses of proceeding in cash (706 USD) in comparison with the traditional technology. On the average maintenance of nitrates in the zucchini grown in the organic system of agriculture was on 27 % below, than in traditional.

The article presents the biochemical indicators of the production of vegetable crops on the basis of years of research. It was established that the content of sugars, ascorbic acid, carotin was more dependent on the meteorological conditions of the growing season than on the fertilizer system. Fertilizers, especially nitrogen, significantly influenced the content of nitrates in vegetable products, especially in those plants in which the phase of consumer maturity fell on a period of intensive growth.

In the Republic of Belarus are concentrated significant areas of vegetable crops. An analysis of the scientific literature has shown that vegetable crops place high demands on soil fertility and the level of mineral nutrition. Realization of high productivity of vegetable crops is possible only with the optimal combination of agrochemical characteristics of vegetable crop soil.