Browsing by Subject "Emissionsverringerung"

Now showing 1 - 3 of 3
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    Biogenic Greenhouse Gas Emissions from Agriculture in Europe - Quantification and Mitigation
    (2002) Freibauer, Annette; Zeddies, Jürgen
    This dissertation analyses relevant potential mitigation strategies of biogenic greenhouse gases (GHGs) in the agriculture of the European Union (EU) in light of the Kyoto Protocol. It identifies where important sources and mitigation potentials are located and what uncertainty, environmental ancillary effects and costs are associated with them. Literature reviews are performed and methodologies for environmental assessment and GHG accounting are further developed. On this basis, GHG emissions are quantified and reduction potentials are assessed at European level. In 1995, European agriculture emitted 0.84 ± 0.29 Tg N2O, 8.1 ± 1.9 Tg methane (CH4) and 39 Tg ± 25 carbon dioxide (CO2), which adds up to 470 ± 80 Tg CO2-equivalents or 11% of the overall anthropogenic greenhouse gas emissions of the EU. The detailed methodology developed here adequately resolves regional specifics of agricultural conditions and reduces the methodological uncertainty in the estimates to half of the one in the official national inventories. European agricultural soils will at maximum sequester carbon in the order of 100 Tg a-1 CO2 over the coming years, which may also provide other environmental benefits. The biological potential of bioenergy in the EU allows to substitute for 400 to 800 Tg a-1 CO2-equivalents. From an environmental perspective, the use of perennials, especially of residues and woody biomass, is preferable to intensively grown annual crops. The biological potential for technical GHG reduction measures in EU agriculture is between 100 and 200 Tg a-1 CO2-equivalents. Promising measures promote the extensivation of arable cropping by reducing nitrogen inputs, technological innovation in animal husbandry, which is best accompanied by a further decline in animal numbers, as well as rewetting drained organic soils. Most measures will provide ancillary environmental benefits. Changing the socio-economic and political frame conditions may enhance the GHG mitigation potential.
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    Grundlagenuntersuchungen zur Wirkung neuartiger Ureaseinhibitoren in der Nutztierhaltung
    (2008) Reinhardt-Hanisch, Annett; Hartung, Eberhard
    Due to the agreements held by Germany in international and national programmes to reduce climate and environmental deterioration particularly in relation to ammonia emissions from livestock housing, additional measures have to be taken in order to ensure that international and national objectives will be achieved. Within the framework of a BMBF-funded interdisciplinary research project, new types of urease inhibitors had been tested for application in animal housing. The present work shows the necessary basic studies, which formed the basis for the investigations under conditions similar stall conditions and in practice stall in the second part of the project (LEINKER, 2007). The main objective of the present work was to investigate the effect of different urease inhibitors on urea hydrolysis, and thus to quantify the ammonia release of urea applied on cattle slurry under standardized, reproducible and controlled laboratory conditions and to investigate possible influencing factors (Pre-screening). Subsequent objectives result in the following: development of an appropriate measuring system and implementation of a standardized test, study of various urease inhibitors at different substrate temperatures and inhibitor concentrations, selection of the urease inhibitor which has the best reduction effect, and quantification of other factors influencing the effect of the selected urease inhibitor. In order to assess the inhibitor effect, the protonated ammonium and the available ammonia in slurry should be detected by means of conducting slurry analysis. In addition, the first indications of a long-term effect of the selected urease inhibitor, its impact on biogas accumulation, and its effect on liquid swine manure should be derived. In order to carry out the investigations, a water-tank measuring system had been configured and validated. The 28 measuring tanks of the measurement system, where each tank was filled by 2 l of slurry, worked according to the principle of dynamic chamber and were kept at constant temperature using a water bath. A gas analysis based on NDIR spectroscopy had been used in order to sustain continuous measurement of ammonia concentrations in the measuring device. The standardized test, applied in the main experiments, had been developed in the preliminary experiments. Among the five pre screened urease inhibitors (four new active agents + reference NBTPT active ingredient), the urease inhibitor D is selected for further investigations in the project, as this is the best inhibitor having significant reduction effect, which was in general dependent on the substrate temperature and the inhibitor concentration in terms of ammonia release. For an effective reduction of ammonia release, it seems useful to deploy more often smaller quantities of the inhibitor. The urease inhibitor D showed a significant reduction effect regardless of the origin and the layer thickness of the respective liquid manure. In comparison with the urease inhibitor D treated variants, more urea is significantly converted to ammonia and ammonium-nitrogen at a layer thickness of 4 mm than at a layer thickness of 90 mm. Apart from the ammonia release, the resulting nitrogen balance of all the tests showed no indication of further significant gaseous nitrogen losses, e.g. as nitrous oxide. In the experiments, no significant influence of urease inhibitor D had been detected on the (urea independent) basic release of ammonia from the respective liquid manure resulting from the degradation of organic substances. In practice, this means that the use of urease inhibitors is only reasonable in the presence of urea. The preliminary related investigations showed that the duration effect of the urease inhibitor D is dependent on temperature; no adverse effects caused by the inhibitor D of treated slurry on the biogas accumulation. Similar relations, as in cattle slurry, had been recognized and showed for the urease inhibitor D in pig slurry. As part of the investigations, a urease inhibitor is selected for cattle and pig slurry urea hydrolysis, and thus the ammonia release is significantly reduced. The basic investigations afforded an important contribution to the expansion of knowledge in this area, and lead on the other hand to develop new techniques in order to reduce the ammonia emissions from livestock housing.
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    Kraftstoffverbrauch beim Einsatz von Ackerschleppern im besonderen Hinblick auf die CO2-Emissionen
    (2006) Schreiber, Matthias; Kutzbach, Heinz Dieter
    Agricultural tractors are currently almost exclusively driven by diesel engines. By rising fuel prices and growing ecological awareness concerning CO2-emissions and preservation of fossil fuel resources the importance of fuel consumption has been increasing. Generally, the substitution of diesel by alternative fuel based on vegetable oil is possible, however the potential for the substitution is limited by the scarcity of agricultural farmland and categorized as low. The cost savings are not very big due to higher fuel consumption with bio fuel. Therefore, only the reduction of fuel consumption for different agricultural operations and if applicable the reorganisation of the production chains can contribute to a sustained reduction of fuel consumption and costs. In this thesis the basic influencing factors on fuel consumption of tractors are shown. Field tests are only of limited usefulness for the examination of single influencing variables. For those studies a model had to be developed. The presented model is based on the status of science concerning engine and transmission performances as well as tractive performance for agricultural tractors and is combined with the ASAE-Standard 497.4-model for the tractive force needed to pull the implement. As existing tyre-soil-models are only of limited use to predict tractive performance in the field and to deliver these values to the tractor model, an independent traction prediction model was developed. It is based on empirical equations, which were parameterized on the basis of numerous field tests. Furthermore, the influence of the fuel consumption for turning over in the headlands and for transportation work were investigated and considered in the model. The new model was implemented into the software Matlab to determine fuel consumption for different agricultural work and defined parameter variations. The calculated values were compared to the results of field tests with a special equipped tractor at the University of Hohenheim to validate the model. The model was used to investigate the influence of numerous influencing parameters, the effect on fuel consumption was shown and optimization strategies were developed. The saving potential by the optimization of the working process is up to 30 % for different implements, depending on the current state. For this purpose the tractive efficiency must be maximized by the correct weight of the tractor and the correct tyres, tractor and implement must be adjusted ideal, four wheel drive and differential locks must be used if necessary and the transmission ratio must be chosen to run the engine close to the optimum working point with the optimum engine load. Besides the process optimisation it is important to deliver standard values for the fuel consumption for different working operations and production chains for the practical use. For the presented model a large number of parameters has to be determined, thus it is of limited use to calculate standard values. Furthermore, it is too accurate for those calculations. Therefore, the model was used to obtain simplified equations for a quick and simple calculation of fuel consumption values, considering the major criteria of engine, transmission and tractive performance of the tractor as the drawbar pull and the needed PTO-power of the implement. On the basis of these equations, implemented into Microsoft Excel, the required standard values for fuel consumption can be calculated for different tractors with implements of different size and defined soil conditions. However, the required data of some implements are not complete. For the most important agricultural implements these parameters were determined by measurements or collected from KTBL- or FAT-values. The results for different operations and production chains are correlating well with values measured in the field. The effect of the field size or the distance between field and the farm yard on fuel consumption can be shown as well. The saving potential by changing the whole production chain (like zero tillage) is enormous, however, there are horticultural and economical external effects. As those economical effects can hardly be estimated, the conversion of the production chain has to be reviewed for the individual case. In the future the importance of fuel consumption will increase. Different saving strategies will gain in importance in order to optimize agricultural operations with respect to fuel consumption. The approach of this thesis can be used to show saving potentials, to develop optimization strategies and to calculate values for the fuel consumption of different agricultural operations.