Ökologische Untersuchungen zur Nitrifikation in Nord-und Ostsee

Ammonia, nitrite and nitrate were regularly estimated at several stations in the Kieler Bucht (western Baltic Sea) since November 1964. There are considerable seasonal changes in the contents of these 3 nitrogen compounds with impressive maxima of nitrite and nitrate in February or at the beginning of March. The great increase of nitrite and nitrate during the winter and also a smaller increase in summer are mainly caused by oxidation of ammonia, first to nitrite and then to nitrate, by nitrifying bacteria. In consequence chemoautotrophic nitrite- and nitratebacteria could be found in the water as well as in sediments all over the Kieler Bucht and also in the North Sea around the isle of Helgoland. These nitrifying bacteria are able to oxidize ammonia or nitrite in salinity conditions typical for the western Baltic Sea and the North Sea

Adubação nitrogenada em videiras jovens e em fase produtiva: recuperação e distribuição na planta do nitrogênio adicionado no solo.

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Soil physical properties affected by soil management and crop rotation in a long term experiment in Southern Brazil

The main objective of this work is to evaluate soil physical properties affected by cover crop rotations and soil management after 19 years of applying NoTill and Conventional Tillage systems with different winter species on a clayey Oxisol in South Brazil

Cobre em solos cultivados com a videira na Serra Gaúcha do Rio Grande do Sul.

O presente trabalho objetivou determinar as formas de cobre e a cinética de dessorção em solos cultivados com a videira e submetidos a sucessivas aplicações de fungicidas cúpricos.bitstream/CNPUV/10103/1/cot086.pd

Mineralogical changes caused by grape production in a regosol from subtropical Brazilian climate.

Purpose Inadequate soil use and management practices promote commonly negative impacts on the soil constituents and their properties, with consequences to ecosystems. As the soil mineralogy can be permanently altered due to soil use, this approach can be used as a tool to monitor the anthropogenic pressure. The objective of the present study was to assess the mineralogical alterations of a Brazilian regosol used for grape production for 40 years in comparison with a soil under natural vegetation (forest), aiming to discuss anthropogenic pressure on soils. Material and methods Soil samples were collected at depths of 0?0.20 and 0.20?0.40 m from vineyard production and natural vegetation sites. Physical and chemical parameters were analysed by classic approaches. Mineralogical analyses were carried out on <2 mm, silt and clay fractions. Clay minerals were estimated by the relative percentage of peak surface area of the X-ray patterns. Results and discussion Grape production reduced the organic matter content by 28% and the clay content by 23% resulting in a decreasing cation exchange capacity. A similar clay fraction was observed in both soils, containing kaolinite, illite/mica and vermiculite with hydroxy-Al polymers interlayered. Neither gibbsite nor chlorite was found. However, in the soil under native vegetation, the proportion of illite (79 %) was higher than vermiculite (21 %). Whereas, in the soil used for grape production during 40 years, the formation of vermiculite was promoted. Conclusions Grape production alters the proportions of soil constituents of the regosol, reducing clay fraction and organic matter contents, as well as promoting changes in the soil clay minerals with the formation of vermiculite to the detriment of illite, which suggests weathering acceleration and susceptibility to anthropogenic pressure. Recommendations and perspectives Ecosystems in tropical and subtropical climates can be more easily and permanently altered due to anthropogenic pressure, mainly as a consequence of a great magnitude of phenomena such as temperature amplitude and rainfall that occurs in these regions. This is more worrying when soils are located on steep grades with a high anthropogenic pressure, like regosols in Southern Brazil. Thus, this study suggests that changes in soil mineralogy can be used as an important tool to assess anthropogenic pressure in ecosystems and that soil quality maintenance should be a priority in sensible landscapes to maintain the ecosystem quality

Highly conductive grain boundaries in cold-sintered barium zirconate-based proton conductors

Proton-conducting barium zirconate ceramics have shown large potential for efficient electrochemical conversion and separation processes at intermediate operation temperatures. The high energy efficiency, robustness, and intermediate-temperature operation (500-650 °C) make proton-conducting cells promising candidates for future energy conversion systems. However, the major disadvantages of these materials are the inevitable high-sintering temperatures (>1500 °C), leading to Ba-evaporation and formation of high-resistance grain boundaries, which dominate the electrochemical performance. Here, we introduce a novel processing route for proton-conducting barium zirconates, which, on the one hand, significantly lowers the maximum processing temperature and, on the other hand, overcomes the dominating influence of grain boundaries on total conductivity. The key step of this novel processing route is the cold sintering of the powder using pure water as a sintering aid to consolidate BaZrCeYO (BZCY) at 350 °C. We show that clean grain boundaries with a high acceptor-dopant concentration are preserved thanks to the recovery of the perovskite phase during thermal treatment at 1300 °C. This compensates the interfacial core charge, resulting in highly conductive grain boundaries, which do not limit the total conductivity. Consequently, dense BZCY electrolytes produced by our novel approach outperform the conductivity of conventionally sintered BZCY irrespective of the significantly lower maximum processing temperature and its nanocrystalline microstructure. Our presented approach opens up new possibilities for grain boundary engineering and might facilitate novel co-sintering pathways for barium zirconate-based components.The authors acknowledge Dr Doris Sebold for help with SEM investigations and Dr Yoo Jung Sohn for assistance with HT-XRD measurements. M. K. acknowledges financial support from the DFG under project number MA 1280/69-1. Additionally, D. J. and W. R. thank the DFG for funding within the Emmy Noether program (RH 146/1-1). A. V. expresses gratitude to Dr Ivan Povstugar for his insightful discussions on the quality of APT data and its reconstruction. The authors thank Hitachi High-Technologies for providing access to the HF5000 STEM located at ER-C

Avaliação do teor de nitrogênio, aminoácidos e proteínas em folhas e ramos do ano de macieiras submetidas a aplicação foliar de nitrogênio.

As aplicações foliares de nitrogênio (N), em tradicionais países produtores de frutas, quando necessárias, têm sido usadas para complementar à adubação via solo. O presente trabalho objetivou avaliar os teores totais de N, aminoácidos e proteínas nas folhas e nos ramos do ano de macieiras submetidas a aplicações foliares. O trabalho foi conduzido em um pomar de macieira da cultivar Eva, safra 2007/08, na área experimental do Colégio Politécnico da Universidade Federal de Santa Maria (UFSM), em Santa Maria (RS), sobre um Planossolo Hidromórfico. Os tratamentos consistiram de uma e duas aplicações foliares de 0 (água); 1,11; 2,23; 3,31; 4,41 e 5,51g de N planta-1. Nas macieiras submetidas a uma aplicação das doses de N, aos 20 dias após a aplicação, se coletou oito folhas completas (limbo + pecíolo) do terço médio dos ramos do ano, nos diferentes lados da planta e quatro ramos do ano em cada planta. Nas macieiras que receberam duas aplicações das doses de N, aos 16 dias após a aplicação, se coletou oito folhas completas e quatro ramos do ano. Depois de cada coleta, as folhas e os ramos foram lavadas com água destilada, para a remoção do excesso de N e preparados para a análise dos totais de N, aminoácidos e proteínas. Os resultados mostram que a aplicação foliar de doses de N em uma e duas vezes aumentou o teor do nutriente nas folhas, porém não afetou o teor de aminoácidos e proteínas. A aplicação de doses de nitrogênio em uma e duas vezes não afetou o teor de nitrogênio, aminoácido e proteína nos ramos do ano