Winter wheat is one of the most common major food crops in the world. Wheat grain value is determined by high content of protein, fat, and carbohydrates. Cultivation of winter wheat is beneficial, as the resulting product has a low cost. Winter wheat is a high-yield crop (second only to rice). The average yield of the winter wheat in the Russian Federation is 30 t/ha, while in the advanced farms it reaches to 50-60 t/ha. The highest yield in the Russian Federation was obtained in the Krasnodar Territory, amounting for 103.6 kg/ha, whereas worldwide, in Canada-170 kg/ha. Protein content greatly depends on soil and climatic conditions. In wheat and other crops, protein content increases in the regions from north to south and from east to west. Aridity of air, solar radiation, high concentrations of nitrogen in the soil, and the level of agricultural technology affect the quality of the grain. The Department of Agricultural Chemistry and Plant Physiology of the Federal State Budgetary Educational Institution of Higher Professional Education (FSBI HPO) "Stavropol State Agrarian University" carried out studies in the 2010-2014 on leached chernozem of the Stavropol elevation. The conducted studies aimed at targeting of winter wheat (Zustrich cultivar) yield in the zone of moderate humidity based on the optimization of fertilizer application. The article presents the four-year data on the effect of fertilization rates on the dynamics of labile phosphorus and exchangeable potassium in the soil layer of 0-20 cm, as well as on the yield and quality of winter wheat (Zustrich cultivar), cultivated on leached chernozem in the zone of erratic moistening of the Stavropol Territory. According to the results based on three years data, at the expected harvest of 6.0 t/ha, the reliability of the yield targeting on leached chernozem of Stavropol elevation, when applying N 126 P 80 K 72, was 99% according to the calculation method suggested by V. Ageev (Esaulko & Ustimenko, 2014).

Based on the conducted research, experimental data were obtained that allowed recommending a calculation and balance method for determining fertilizer rates for constructing a fertilizer calculation system, which allowed obtaining the maximum yield of winter wheat (6.01 t•ha-1) after the forecrop peas on leached chernozem. The optimal combination of systems for fertilizing winter wheat after its forecrop peas with methods and techniques for placing mineral fertilizer in a 0-20 cm soil layer has been established.Obtaining high and stable yields with good quality of grain production of winter wheat, preservation and improvement of soil fertility, improvement of economic indicators in farms is impossible without the use of a rationally composed fertilizer system. It implies a reduction in doses of fertilizers, an increase in soil stocks of nutrients. Modern fertilizer systems should be based on biologicalization of agriculture, combined with the rational use of mineral and organic fertilizers, in relation to specific soil-climatic and economic conditions, taking into account the requirements of ecology and adaptive farming. Different methods and techniques of tillage affect its structural state, the structure of the arable layer, water-air, nutrient and thermal regimes, thereby affecting the growth conditions of plants, which affects their productivity.The main objective of the research was to determine the influence of fertilizer systems, methods and techniques of tillage on the food regime of leached chernozem and the productivity of winter wheat.The studies were carried out in an experimental crop rotation of the permanent study area located at the experimental station of the Stavropol State Agrarian University. The station is a longterm experience "Theoretical and technological bases of biogeochemical flows of substances in agrolandscapes", registered in the certificates record of long-term experiments of the GeoNetwork of the All-Russian Scientific Research Institute of Agrochemistry of the Russian Federation.

Background. Some natural carotenoids have anti-carcinogenic, anti-mutagenic, and immunomodifying activity and may be considered as potential agents for chemoprevention of cancer. Objective: to study pharmacokinetics of beta-carotene, cantaxantene, lycopene, and carotene-containing compounds created on the base of the mentioned substances. Materials and methods. The study used carotene-containing drugs, which we previously created, such as Betask, Kaskatol, Tomatol, natural carotene-tocopherol complex derived from cankerberry. The research was conducted on mice, rats, rabbits, dogs, piglets, monkeys (Javanese macaque); the observations also involved healthy donors and patients with colorectal cancer before surgery. Carotenoid and retinoid detection was made by high performance liquid chromatography in blood plasma and liver tissue. Results. Comparative analysis of pharmacokinetics of the studied carotenoids demonstrates their relatively low absorption in animals. Bioavailability varies significantly among species; and it increases in the following order: dogs, rabbits, mice, rat, piglets, humans. Pharmacokinetics of carotenoids and carotene-containing compounds was studied with single and multiple administration per os. Cantaxantene and lycopene have a better bioavailability as compared to synthetic beta-carotene. Pharmacokinetics of synthetic carotenes and carotenoids of carotene-containing compounds has no significant differences. Beta-carotene in natural carotene-tocopherol complex has higher bioavailability (2-4 fold higher) as compared to synthetic beta-carotene. Regular complex administration into monkeys results in enhanced beta-carotene levels in blood serum of the animals and inhibits chemically induced carcinogenesis. The patients’ intake of beta-carotene in the pre-operational period was associated with the enhanced pro-vitamin levels in blood serum and stimulation of a number of cellular immune parameters. Conclusions. The studied carotenoids and carotene-containing compounds may be used in combined antitumor therapy and as treatment and prophylactics agents in cancer risk groups.

The main factors determining the change of the ecological situation in the zone of salinized compact chernozems distribution are the hydrological state, waterlogging, water erosion and the use of chemical crop products. In order to prevent further progress in the degradation of these lands, a number of activities are required. The most important task is to ensure the expanded reproduction of soil fertility. Its solution suggests the systematic application of fertilizers. A great advantage on saline soils should be given to organic fertilizers in order to maintain stocks of humus. The value of humus in their composition increases even more due to the fact that it reduces the possible negative impact on plants of some components of the mineral part of the soil, improves its water-physical properties. Humus limits the leaching of nitrogen caused by uncontrolled mineralization, increases the filtering and buffering effect of the soil and groundwater. In the intensive farming system, a deficit-free humus balance can be observed by combining the use of organic and mineral fertilizers. At the same time, the use of higher doses of them leads to pollution of the soil, plants and the environment. Therefore, the use of fertilizers should be carried out taking into account the biological needs of plants and specific soil conditions. On saline soils, due to a significant reduction in plant growth parameters and the biomass formed by them, the removal of nutrients in the composition of the primary and secondary crop significantly decreases. In addition, they are characterized by relatively high osmotic potential, which may further increase due to the application of higher doses of fertilizers. Therefore, in these conditions, moderate and small doses of mineral fertilizers are effective, and they meet the needs of plants and the interests of the soil ecology.

The results of experimental research of loads acting in rubber and metallic hinges of track chain for agricultural tractors of class 3 are shown. Tracked tractor was equipped with a caterpillar with rubber-metallic hinges of sequential type of five towing point variant with restrictor of radial deformation. To determine the forces acting on hinge was used strain-gauge joint and angle relative to the rotation of track chain was defined. In addition, the research was accompanied by a recording of the following parameters: frequency of rotation of the motor shaft, torque on the shaft of clutch, torque on driving wheel, number of revolutions of the drive wheel, number of revolutions of track-measuring device. These parameters were determined during tractor movement at different gears with changing range of hook loads from 15 to 32 kN. Experimental studies and their analysis showed that the restrictor is in contact with the surface of towing point during movement of the tractor in all gears when hooking load exceeds 15 kN, not only in the driving area of caterpillar tracks, but also on the supporting unit. Rubber elements on the contour of the tracked bypass are subject to deformation in the radial direction. The radial displacement is not constant and on free unit values 0.05...0.15 mm and varies with frequency close to track one. On all parts of caterpillar tracks the twisting of the rubber elements is accompanied by a preliminary deformation in the radial direction. The obtained results allow to substantiate the modes of loading rubber components of track chain hinges for bench testing and when calculating the stress-strain state.