Soy belongs to the most important crops of the world agriculture. Thanks to the combination of two processes: photosynthesis and biological nitrogen fixation, soybean intensively synthesized almost all valuable organic substances. In its grains there are 38-42% crude protein, 18-23% fat, 25-30% carbohydrates, vitamins and minerals. The main task of the Ukrainian breeders today is yield increasing.

The relevant breeding soybean doing increased content of grain protein, fat. Thanks to this, the volumes of the soybean production in the world continues to grow. Being an active clamp of biological nitrogen atmosphere, soy enriches the soil with ecologically pure nitrogen, leaving with crop residues up to 50-90 kg/ha.

The right choice of varieties is one of the decisive conditions for maximum yield. Farmers grow two-three varieties, differing duration of the vegetative period. Soybean is one of the most productive leguminous crops with a high content of grain protein and fat. The amount of area planted with this crop has tended to increase. Soy protein contains essential amino acids, as lysine, threonine, valine 7 %, leucine 1,5 times higher, tryptophan 21% more than the quality standard on protein FAO and the world health organization .

Soybean oil contains about 55% of essential linoleic acid, which is not synthesized by the body and comes only with food. Polyunsaturated fatty acids also oleic - 25%, linolenic - 8%. Saturated fatty acids, such as palmitic and stearic in grain soy compose about 12 %. Carbohydrates soybean (17-25 %) presented a half-soluble sugars: glucose, fructose, sucrose (50%) and insoluble (50%): starch, fiber and others. The first of them is directly absorbed by the body, and others contributed to the activation of useful intestine microflora.

The chemical composition of soy beans is the cause of its use for many sectors of the economy. Primarily, it is the raw material for the oil industry. Products of processing of soy beans, which they get from the press or chemical extraction, widely used in food and technical purposes, and cakes and meal - as high protein supplements to a concentrated fodder.

The aim of the research was to establish regularities of yields and grain quality of different maturity classes soybean varieties, depending on the inoculation of seeds and fertilizers.

The studies were conducted in 2011-2012 in conditions of the Central forest-steppe of Ukraine in the field crop rotation in Terezino in accordance with generally accepted in farming and plant growing methods on blacksoil typical humus in arable soil layer of 3,4-3,6% and pH salt extraction from 6.4 to 6.5. The object of the research - soybean varieties Snow White (early-maturing) and Kyiv 98 (intermediate). The seeds were inoculated on the final density of 600 thousand of plants per 1 hectare. Predecessor - winter wheat. Options fertilizer: 1 - control; 2 - N - 30; 3 - NPK - 30:45:45; 4 - NPK - 30:90:90.

Mineral fertilizers in connection with the variants of the researches made under the major soil cultivation and under spring cultivation. The form of fertilizers - ammonium nitrate (N - 30 %), granulated superphosphate (P₂O₅ - 19) salt and potash (K₂O - 40 %). The research included sowing soybean inoculation risobofitom (2 l/t) seeds and without inoculation. Record harvest was performed by direct harvesting combine “Sampo-130” and weighing from each site, the content of fat and protein in grain soybeans was determined by using the method of infrared spectrometry analyzer NIP Scanner 4250 with computer software ADI DM 3114.

Statistical processing of the data research conducted by analysis of variance. Highest soybean variety Snow White which belongs to the group of early-ripening, received in the version with application N30P90К90 is 31.9 C/ha, while in the application of fertilizers and inoculation of 18,2 C/ha, an increase of 13.7 C/ha Yield of mid-maturing cultivars Kyiv 98 version with application N₃₀P₉₀К₉₀ - 26,1 C/ha, whereas in the application of fertilizers and inoculation 15,2 kg/ha, growth of the soybean crop was 10.9 C/ha

We have found that the high content of fat was in the grain variety Snow White and fluctuated within 21,78-22,81 % depending on the elements of technology of cultivation. Range of fat content in the grain of Kyiv 98 varied from 20,02 to 21,92 %.

Analysis of changes of fat content in grain soybean variety Snow White has allowed to establish, that this figure increased to 1.60 to one - 1.94 g/kg per 100 kg of increase of productivity depending on fertilizers and inoculation, and that of Kyiv 98, respectively 1.49 - 1,90g/kg.

In the grain soybeans a low level of domestication contains on average 16-17% fat, and the well-cultivated samples reaches 24-26%. We found that the high content of fat was in the grain variety Snow White and fluctuated within 21,78-22,81 % depending on the elements of technology of cultivation. Range of fat content in the Kyiv 98 grain varied from 20,02 to 21,92%.

Absolute levels of the protein content in grain were largely depended on the inoculation of seeds and activity of the functioning of the symbiotic system. Protein content in seeds was higher at the inoculation held comparison with the similar options for the system of fertilizers, but without seeds inoculation.

It should be noted that the protein content in grain soy depended on the duration of the vegetation period and biological characteristics of the variety and in our research has changed from 39,56 to 42,64%.

Low protein content was in the grain soy Snow White (39,56-40,96 %) and highest one had soybean variety Kyiv 98 - 39,91-42,64 in the context of the researched variants. It is worth noting that protein had a reciprocal relationship, regarding the increase of the level of yield and fat content in the grain. This relationship continued for all varieties and options experience with doses of fertilizers. We found that for every 100 kg of increase of the yield of protein content in grain of options without the use of inoculation decreased to 2,61-3,00г/kg of Snow White variety; 2,77-3,22g/kg - grade Kyiv 98 and respectively in versions with application of inoculation 2.06 to 2,84 and 2,05-2,14.

In result of studies on the impact of the action of the bacterial preparation risobofit on background of different levels of mineral fertilizers on the yield and quality of soybean grain found that all factors affect these indicators. The highest yield of Snow White soybean variety received in the version with application of fertilizers doses N₃₀P₉₀К₉₀ and presowing seeds inoculation is 31.9 C/ha, while in the application of fertilizers 18,2 C/ha, the growth was 12.7 centner/ha, the dependence exists between the yield, content of fat and protein in grains soybeans. So, the higher the yield, the lower protein content in studied grain soy varieties and higher percentage of fat.

So, we have justified the peculiarities of the yields formation and grain quality soybean varieties of different maturity classes, depend on the inoculation of seeds and fertilizers on blacksoil typical for the Central forest-steppe of Ukraine. The highest yield of ripened soybean variety Snow White received in the version with application of fertilizers doses N₃₀P₉₀К₉₀ and presowing seeds inoculation is 31.9 C/ha, established stable relationship between yield, content of fat and protein in grains soybeans. So, the higher the yield, the lower protein content in grain of soy in the studied cultivars and higher percentage of fat. The range of change of fat content in seeds of soya in the context of doses of fertilizers application, inoculation and varieties, demonstrates the significant potential of soy on the accumulation of fat in the seeds and growth of its gross harvest of the crop. Absolute levels of the protein content in grain were largely dependent on the inoculation of seeds and activity of the functioning of the symbiotic system.

Key words: soybean, technology of cultivation, fertilizers, bacterial fertilizers, protein, fat, productivity.