No abstract

Deep drilling at the Vostok Station has reached the surface of subglacial Lake Vostok (LV) twice-in February 2012 and January 2015. As a result, three replicate cores from boreholes 5G-1, 5G-2 and 5G-3 became available for detailed and revalidation analyses of the 230 m thickness of the accreted ice, down to its contact with water at 3769 m below the surface. The study reveals that the concentration of gases in the lake water beneath Vostok is unexpectedly low. A clear signature of the melt water in the surface layer of the lake, which is subject to refreezing on the icy ceiling of LV, has been discerned in the three different properties of the accreted ice: the ice texture, the isotopic and the gas content of the ice. These sets of data indicate in concert that poor mixing of the melt (and hydrothermal) water with the resident lake water and pronounced spatial and/or temporal variability of local hydrological conditions are likely to be the characteristics of the southern end of the lake. The latter implies that the surface water may be not representative enough to study LV's behaviour, and that direct sampling of the lake at different depths is needed in order to move ahead with our understanding of the lake's hydrological regime.

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The Astrakhan region is the main vegetable-growing and melon-growing center of Russia, characterized by favorable agro–climatic conditions for growing vegetable and gourd crops. The agro-climatic conditions of the region make it possible to obtain the earliest, highest and most stable yields. Currently, in the southern regions, the problem of reducing the use of mineral fertilizers and pesticides in agriculture with their replacement by biological methods of plant protection is quite acute. Biological methods, in comparison with chemical means of protection, are distinguished by the selectivity of impact and by the environmental safety. Preliminary studies have shown that the studied laboratory sample of the agent based on Bacillus atrophaeus B‐11474 has pronounced fungistatic and growth-stimulating activities, which were confirmed by the field research results. The studied laboratory sample of the agent had a positive effect on the germination, development and biometric parameters of watermelon. The sample helped to increase productivity, reduce anthracnose, improve the qualitative and quantitative indicators of the cultivated crop. The prospects for using the triple treatment (spraying the bottom of the furrow and double spillage under the root of the plant with a laboratory sample of the agent have been established. In general, the use of a biological agent in the cultivation of watermelon in the fields of the Astrakhan region will make it possible to obtain environmentally friendly and safe products.

In the conditions of the Astrakhan region Alternaria blight is one of the most widespread and harmful diseases. The application of only chemical preparations often leads to the emergence of resistant forms of pathogens. One of the methods to solve this problem is the combined usage of chemical and biological preparations. The article shows the possible loss of yield of potato tubers in the absence of measures to control this disease. Is it described biological preparations that are produced on the basis of one of the most diverse and naturally diffused bacteria of the Bacillus genus, which are able to inhibit the development of a wide range of plant pathogenic fungi. The characteristics of the variety, conditions and methods of research are given. The article presents the results of trials of the combined application of chemical and biological preparations against potato Alternaria blight under irrigated conditions of the Volga delta with cultivation of potato under on drip irrigation. It was noted that pre-planting treatment of potato tubers with biological and chemical preparations contributed to the growth of field germination rate by 4,3-7,6%. The combination of preplant treatment with spraying of vegetative plants positively influenced the biometric parameters of potato bushes, increasing the number and weight of leaves, the average height and number of productive stems, as well as the mass of tops and tubers. In comparison with the control variant without treatment the leaf surface area increased by 15-29%. The results of the estimation of effectiveness of the combined use of biological and chemical preparations against potato Alternaria blight are presented. It was established that the degree of the Alternaria blight development during the vegetation period was below the control by 30-76%. It was also mentioned an increase in the productivity of cultivated plants without a significant decrease in the quality of potato tubers.