Растениеводство. Садоводство

Phytoplankton constitutes a key part of all aquatic ecosystems. It produces organic matter, thus forming the first level of food chains in water bodies. In addition, phytoplankton plays a major role in the water quality formation. The studies of algocoenosis always remain relevant, since the obtained data provides important information on the ecological status of water bodies. This information can subsequently be used for planning and implementing environmental measures, which are particularly significant for water bodies located in specially protected areas. National parks existing for the purposes of nature preservation, education and research are also designed for tourism, which makes their ecosystems more vulnerable. Population residing in such territories and its economic activity may also carry some environmental risks, which necessitates regular complex observations. This paper covers the state of spring phytoplankton community of Lake Kenozero in 2018, its qualitative and quantitative characteristics (species composition, abundance and biomass). In the course of research, we identified 70 phytoplankton taxa belonging to seven divisions: Bacillariophyta, Dinophyta, Chlorophyta, Cyanophyta, Chrysophyta, Xanthophyta and Euglenophyta. The dominant species complex included diatoms (Asterionella formosa, Melosira granulata, Tabellaria fenestrata), representatives of Dinophyta (Gymnodinium sp.), as well as small euglenoids. Species diversity was estimated using the Shannon-Weaver index. Aquatic environment contamination was assessed, i.e. the saprobity index was calculated and the class of surface water quality was determined. According to the water quality classification of water bodies and watercourses by hydrobiological indicators, Lake Kenozero was assigned the second class of water quality (moderately polluted).

Phytoplankton constitutes a key part of all aquatic ecosystems. It produces organic matter, thus forming the first level of food chains in water bodies. In addition, phytoplankton plays a major role in the water quality formation. The studies of algocoenosis always remain relevant, since the obtained data provides important information on the ecological status of water bodies. This information can subsequently be used for planning and implementing environmental measures, which are particularly significant for water bodies located in specially protected areas. National parks existing for the purposes of nature preservation, education and research are also designed for tourism, which makes their ecosystems more vulnerable. Population residing in such territories and its economic activity may also carry some environmental risks, which necessitates regular complex observations. This paper covers the state of spring phytoplankton community of Lake Kenozero in 2018, its qualitative and quantitative characteristics (species composition, abundance and biomass). In the course of research, we identified 70 phytoplankton taxa belonging to seven divisions: Bacillariophyta, Dinophyta, Chlorophyta, Cyanophyta, Chrysophyta, Xanthophyta and Euglenophyta. The dominant species complex included diatoms (Asterionella formosa, Melosira granulata, Tabellaria fenestrata), representatives of Dinophyta (Gymnodinium sp.), as well as small euglenoids. Species diversity was estimated using the Shannon-Weaver index. Aquatic environment contamination was assessed, i.e. the saprobity index was calculated and the class of surface water quality was determined. According to the water quality classification of water bodies and watercourses by hydrobiological indicators, Lake Kenozero was assigned the second class of water quality (moderately polluted). Citation: Otchenash NG, Dvoryankin GA, Imant EN (2019) State of spring phytoplankton and quality of the Kenozero waters in 2018. Arctic Environmental Research 19(1): 43–48. https://doi.org/10.3897/issn2541-8416.2019.19.1.43

The research results on studying of an influence of an inoculation and mineral nitrogen application for symbiotic activity and seed production of different varieties of soya bean are presented in this article. All these researches were conducted in the All-Russia Scientific Research Institute of grain legumes and cereal crops in 2011- 2013. Symbiotic and productive ability of new soya varieties Zusha and Mezenka in comparison with the standard Lantsetnaya variety is studied. It is established that formation of the symbiotic device and its activity depended on a preseeding inoculation of seeds bacterial fertilizer (nitragin) and also on presence of spontaneous populations of rhizobium in the soil. The period duration of a symbiotic nitrogen-fixing depended on varietal features and was longer at Zusha and Mezenka's more late-season varieties. Seeds inoculation by nitragin was surpassed in efficiency of mineral nitrogen application in a dose of 60 kg per hectare. An addition yield reached 2,6 c/hectare. Different reactions of varieties when forming a crop on distribution of rainfall during the growth season was noted. Having prevalence of rainfall in the first half of summer on formation of a crop early ripening varieties which used spring soil deposits of moisture and rainfall of May-June more rationally had advantage, less suffering from a July- August drought and a heat. More late-ripening varieties had advantage in case of better providing with rains if the second half of summer. The heavy yield – 30,7 c/hectare (on average for 3 years) created Mezenka variety. doi: 10.15217/279700