Перегляд за Автор "Medinets, Serhii V."

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  • Ескіз
    Документ
    Changes in soil carbon and nitrogen dynamics during a three year crop rotation on a chernozem soil in the Southern Ukraine
    (Одеський національний університет імені І. І. Мечникова, 2014) Medinets, Serhii V.; Skiba, U. M.; Medinets, Volodymyr I.; Bilanchyn, Yaroslav M.; Pitsyk, Vasyl Z.; Hoshurenko, L. M.; Kotogura, S. S.; Медінець, Сергій Володимирович; Скіба, У. М.; Медінець, Володимир Іванович; Біланчин, Ярослав Михайлович; Піцик, Василь Зіновійович; Гошуренко, Л. M.; Котогура, С. С.; Мединец, Сергей Владимирович; Скиба, У. М.; Мединец, Владимир Иванович; Биланчин, Ярослав Михайлович; Пицык, Василий Зиновьевич
    Soils in the southern Ukraine have been reported to have lost 32% to 40%, or 51 to 71 t ha-1 of their original soil organic matter (SOM) pool between 1881-1981, mainly due to inappropriate soil management by collective farms during 1930-1981. In this period agricultural management was directed towards irresponsible expansion of arable fields and short-term yield increases. Modern, sustainable agricultural management is slowly being introduced. There is a need to assess to what extend such methods stabilize and build new SOM to support and increase fertility both in the short and long-term. This study investigates the influence of a modern crop rotation (onion-tomato-barley) on one field, which was tilled, fertilized, irrigated and harvested in response to the crops needs, on the dynamics of total organic carbon (TOC) and total nitrogen (TN) storage in the fertile topsoil of a Chernozem typical for southern Ukraine. Crop residue remained on the field. The results of three years (2007-2009) of quarterly monitoring of the key topsoil parameters TOC, TN, extractable mineral N (NH4+, NO3-, NO2-), pH, potential net N mineralisation (MIN) and nitrification (NITR) rates and physical characteristics (bulk density, soil texture) are discussed. Moderate (114 kg N ha-1 yr-1) and low (28 kg N ha-1 yr-1) N fertilizer applications together with adequate drip irrigation for onion and tomato and incorporation of plant residue did significantly change the C and N pools. Total organic carbon and TN contents of the topsoil horizon (0-74 cm) were found to increase by 20% (26.8 t C ha-1) and 38% (5.9 t N ha-1), respectively. Largest increases were measured in the surface layer (0-27 cm) with a 45% increase in TOC and a 36% increase in TN content. The largest average soil NH4 + content of the topsoil horizon (0- 74 cm) was observed in 2009 under barley (154.9±41.3 kg N ha-1) and the maximum average NO3 - content was 166.9±44.5 kg N ha-1 under tomato in 2008. Mineralisation and nitrification rates significantly varied between years and with season and were largest in the first year of the crop rotation (onion), 41.0±57.3 kg N ha-1 and 36.6±74.4 kg N ha-1 for MIN and NITR, respectively. The incorporation of plant residues and efficient N fertilizer applications within a crop rotation appeared to be effective in stabilizing the existing SOM and promoting SOM build-up.
  • Ескіз
    Документ
    Investigations of intercon Nections of Physicalchemical and phytoplankton characteristics in the north-western part of the Black Sea (Zmiinyi Island area)
    (Одеський нац. ун-т, 2015) Kovalova, N. V.; Medinets, Volodymyr I.; Dereziuk, N. V.; Medinets, Serhii V.; Morozov, V. M.; Kovalova, Ye. O.; Ковальова, Н. В.; Медінець, Володимир Іванович; Дерезюк, Н. В.; Медінець, Сергій Володимирович; Морозов, В. М.; Ковальова, Є. О.; Ковалева, Н. В.; Мединец, Владимир Иванович; Дерезюк, Н. В.; Мединец, Сергей Владимирович; Морозов, В. Н.; Ковалева, E. А.
    The aim of paper is estimation of interconnections of the Danube River runoff, physical-chemical and phytoplankton characteristics in the north-western part of the Black Sea on the example of the Zmiinyi Island coastal waters. Material for analysis comprised results of hydrological and hydrochemical characteristics of marine environment, photosynthetic pigments concentration and phytoplankton species composition, which have been measured every decade in one point of coastal waters of Zmiinyi island. The results of statistical analysis of the data for 2004-2014 on the coastal waters of the Zmiinyi Island located in the north-western Black Sea 40 km far from the Danube Delta have been considered and analysed in the article. It has been shown that the state of phytoplankton community characteristics is mostly influenced by salinity, transparency and nitrate content, whose levels are formed under the influence of the Danube water runoff. Analysis of phytoplankton community characteristics depending on three types of water masses has shown that the highest values of biomass and abundance, both in general for phytoplankton and for its separate taxonomic groups have been registered in water masses having salinity from 10 to 14‰ formed under the Danube runoff influence.
  • Ескіз
    Документ
    Результаты атмосферно-химических исследований парниковых газов N20 и СН4
    (Одеський національний університет імені І. І. Мечникова, 2014) Мединец, Сергей Владимирович; Медінець, Сергій Володимирович; Medinets, Serhii V.
    В данной работе представлены результаты впервые проведенных на Украине в 2009-2010 гг. атмосферно-химических исследований потоков парниковых газов N2O и CH4 вблизи Одессы, на черноземах южных в рамках международного проекта NitroEurope. Представлены и проанализированы экспериментальные результаты наблюдений для данного региона и типа почв. Рассчитаны годовые бюджеты для метана и закиси азота, оценен фактор эмиссий N2O