Purpose. To determine the features of the leaf surface area formation and the dynamics of growth of the vege­tative mass of various sainfoin species depending on the influence of mineral fertilizers and inoculation. Methods. Field, laboratory, statistical. Results. In the course of experimental studies, the morphological features of plants in the process of growth and development of various sainfoin species were studied. As our studies showed, all sainfoin species had different plant densities, which accordingly affected the leaf surface area. In the budding phase, the leaf surface area of plants of the first year in continuous cultivation ranged from 17.01 to 24.3 thousand m2/ha on average over three years; in particular, from 18.06 to 24.3 – for common sainfoin; 17.6–20.5 – for transcaucasus sainfoin and 17.1–20.3 thousand m2/ha – for sand sainfoin. The maximum leaf surface area of the plants of the first year of cultivation, regardless of its species, was observed during flowering with the application of complete mineral fertilizer (N45P60K90). In areas without fertilizer this figure was much lower. In the experiments, an increase in the leaf surface on all three studied species and sainfoin varieties from the first to the third year of their cultivation was clearly observed. According to the results of gross productivity for 2 mowings, it was found that common sainfoin forms the maximum increase of top with complete mineral fertilizer and seed inoculation – 43.03 t/ha. Conclusions. The productivity of sainfoin crops depended mostly on the application of complete fertilizer at a dose of N45P60K90 + inoculation of seeds. To a much lesser extent, the species of sainfoin and the cutting height of the first mowing of the grass stand affected its productivity. It was revealed that the greatest dynamics of vegetative mass growth was observed in common sainfoin, and the smallest was recorded in sand sainfoin.

In 2011 to 2013 a study was completed for the impact of varying rates of fertilizing onto the indices of productivity for barley agrophytocenosis of Helios and Commandor, in particular, such its components as a number of productive stems, number of seeds per ear, potential biological activity of ear and photosynthetic apparatus. It is found that the level of spring barley agrophytocenosis productivity is subject both to varietal peculiarities and the rate of mineral fertilizer application. When applying N 60P 60K 60 і N 90P 90K 90 the highest potential and biological productivity of Helios and Commandor was recorder as compared against the control. Impact of varying application rates for fertilizers onto the components of ear biological productivity has been scrutinized. The qualitative composition of ear is a clear expression of variety phenotype and identifies the level of biological yield for spring barley. Application of N 60 P 60 K 60 і N 90 P 90 K 90 mineral fertilizers fairly increased the average leaf surface, photosynthetic lead capacity of varieties in 2 to 2.5 times, as well as FAR efficiency coefficient in 1.5 to 2.0 times as against control that thus contributed to the development of highest biological yield of Helios variety phytomass at the level of 14.9 to 15.0, grain – 7.8 to 8.0 ton per ha and, respectively, 12.7 and 7.5 tons per ha for Comandor variety.

Розглянуто значення біологічного зв’язування молекулярного азоту атмосфери в азотному живленні сільсько­гос­подарських культур та збагаченні ґрунтів. Особливу увагу приділено економічному та екологічному значенню біологічного азоту. Охарактеризовано стан та перспективи розвитку досліджень у галузі біологічної фіксації атмосферного азоту, доведено переваги сучасних мікробних азотфіксувальних препаратів порівняно з азотними добривами | The value of biological fixation of air molecular nitrogen in the nitrogen feeding of agricultural crops and enrichment of soils is considered. High priority is paid to the economic and environmental significance of biological nitrogen. The state and prospects of the study of biological fixation of air nitrogen were analyzed; advantages of modern microbial nitrogen fixing preparations in comparison with nitrogen fertilizers have been proved. | Рассмотрено значение биологического связывания молекулярного азота атмосферы в азотном питании сельскохозяйственных культур и обогащении почвы. Особое внимание уделено экономическому и экологическому значению биологического азота. Охарактеризовано сос­тояние и перспективы развития исследований в области биологической фиксации атмосферного азота, доказано преимущества современных микробных азотфиксирующих препаратов по сравнению с азотными удобрениями.

The value of biological fixation of air molecular nitrogen in the nitrogen feeding of agricultural crops and enrichment of soils is considered. High priority is paid to the economic and environmental significance of biological nitrogen. The state and prospects of the study of biological fixation of air nitrogen were analyzed; advantages of modern microbial nitrogen fixing preparations in comparison with nitrogen fertilizers have been proved.

In 2011 to 2013 a study was completed for the impact of varying rates of fertilizing onto the indices of productivity for barley agrophytocenosis of Helios and Commandor, in particular, such its components as a number of productive stems, number of seeds per ear, potential biological activity of ear and photosynthetic apparatus. It is found that the level of spring barley agrophytocenosis productivity is subject both to varietal peculiarities and the rate of mineral fertilizer application. When applying N 60P 60K 60 і N 90P 90K 90 the highest potential and biological productivity of Helios and Commandor was recorder as compared against the control. Impact of varying application rates for fertilizers onto the components of ear biological productivity has been scrutinized. The qualitative composition of ear is a clear expression of variety phenotype and identifies the level of biological yield for spring barley. Application of N 60 P 60 K 60 і N 90 P 90 K 90 mineral fertilizers fairly increased the average leaf surface, photosynthetic lead capacity of varieties in 2 to 2.5 times, as well as FAR efficiency coefficient in 1.5 to 2.0 times as against control that thus contributed to the development of highest biological yield of Helios variety phytomass at the level of 14.9 to 15.0, grain – 7.8 to 8.0 ton per ha and, respectively, 12.7 and 7.5 tons per ha for Comandor variety.