Farm structures are often characterized by regional heterogeneity, agglomeration effects, sub-optimal farm sizes and income disparities. The main objective of this study is to analyze whether this is a result of path dependent structural change, what the determinants of path dependence are, and how it may be overcome. The focus is on the German dairy sector which has been highly regulated and subsidized in the past and faces severe structural deficits. The future of this sector in the process of an ongoing liberalization will be analyzed by applying theoretical concepts of path dependence and path breaking. In these regards, key issues are the actual situation, technological and market trends as well as agricultural policies. The methodology will be based on a participative use of the agent-based model AgriPoliS and participatory laboratory experiments. On the one hand, AgriPoliS will be tested as a tool for stakeholder oriented analysis of mechanisms, trends and policy effects. This part aims to analyze whether and how path dependence of structural change can be overcome on a sector level. In a second part, AgriPoliS will be extended such that human players (farmers, students) can take over the role of agents in the model. This part aims to compare human agents with computer agents in order to overcome single farm path dependence.
In bog ecosystems, vegetation controls key processes such as the retention of carbon, water and nutrients. In northern hemispherical bogs, a shift from Sphagnum- to vascular plant-dominated vegetation is often traced back to Climate Change and increased anthropogenic nitrogen deposition and coincides with substantially reduced capacities in carbon, water and nutrient retention. In southern Patagonia, bogs dominated by Sphagnum and vascular plants coexist since millennia under similar environmental settings. Thus, South Patagonian bogs may serve as ideal examples for the long-term effect of vascular plant invasion on carbon, water and nutrient balances of bog ecosystems. The contemporary balances of carbon and water of both a bog dominated by Sphagnum and vascular plants are determined by CO2- H2O and CH4 flux measurements and an estimation of lateral water losses as well as losses via dissolved organic and inorganic carbon compounds. The high time resolution of simultaneous eddy covariance measurements of CO2 and H2O in both bog types and the strong interaction between climatic variables and the physiology of bog plants allow for direct comparisons of carbon and water fluxes during cold, warm, dry, wet, cloudy or sunny periods. By the combination with leaf-scale measurements of gas exchange and fluorescence, plant-physiological controls of photosynthesis and transpiration can be identified. Long-term peat accumulation rates will be determined by carbon density and age-depth profiles including a characterization of peat humification characteristics. A reciprocal transplantation experiment with incorporated shading, liming and labeled N addition treatments is conducted to explore driving factors affecting competition between Sphagnum and vascular plants as well as the interactions between CO2-, CH4-, and water fluxes and decisive plant functional traits affecting key processes for carbon sequestration and nutrient cycling. Decomposition rates and driving below ground processes are analyzed with a litter bag field experiment and an incubation experiment in the laboratory.
Chlorinated ethylenes are prevalent groundwater contaminants. Numerous studies have addressed the mechanism of their reductive dehalogenation during biodegradation and reaction with zero-valent iron. However, despite insight with purified enzymes and well-characterized chemical model systems, conclusive evidence has been missing that the same mechanisms do indeed prevail in real-world transformations. While dual kinetic isotope effect measurements can provide such lines of evidence, until now this approach has not been possible for chlorinated ethylenes because an adequate method for continuous flow compound specific chlorine isotope analysis has been missing. This study attempts to close this prevalent research gap by a combination of two complementary approaches. (1) A novel analytical method to measure isotope effects for carbon and chlorine. (2) A carefully chosen set of well-defined model reactants representing distinct dehalogenation mechanisms believed to be important in real-world systems. Isotope trends observed in biotic and abiotic environmental dehalogenation will be compared to these model reactions, and the respective mechanistic hypotheses will be confirmed or discarded. With this hypothesis-driven approach it is our goal to elucidate for the first timdehalogenation reactions.
Das Projekt ÖkoKauf der Stadt Wien hat es sich zum Ziel gesetzt, durch die Erstellung von ökologischen Kriterien, Pilotprojekte und durch Bewusstseinsarbeit das Beschaffungswesen im Magistrat Wien weiter zu ökologisieren. In diesem Rahmen widmete sich der Arbeitskreis 'Desinfektionsmittel unter der Leitung der Wiener Umweltanwaltschaft (WUA) der Aufgabe, für Hygienefachleute ein Instrument zur Beurteilung der Auswirkungen von Desinfektionsmitteln auf Gesundheit und Umwelt zu erstellen. Das Österreichische Ökologie-Institut führte eine Daten- und Literaturrecherche durch, das Umweltbundesamt nahm ergän-zende ökotoxikologische Tests an Wirkstoffen und -produkten vor und 'die umweltberatung ermittelte stationsbezogene Desinfektionsmittelverbräuche in Wiener Krankenanstalten. Die Recherche- und Testergebnisse zu Desinfektionsmittelwirkstoffen und -produkten wurden in einer vom IFZ konzipierten und von der Magistratsabteilung 14 realisierten Datenbank zusammengefasst. Um die ökotoxikologischen Produkteigenschaften vergleichbar zu machen, wurde vom IFZ ein Bewertungsraster entwickelt und in die Datenbank integriert. Dabei werden nachteilige Wirkungen auf die Gesundheit anhand von vier Wirkungskategorien erfasst: Akute Giftigkeit; Reizwirkung auf die Haut; Sensibilisierung, allergenes Potenzial sowie Erbgutschädigende, krebserzeugende und fruchtschädigende Eigenschaften. Zusammen mit der Berücksichtigung des Verhaltens in Oberflächengewässern (Abbauverhalten, Bioakkumulationspotenzial, Toxizität für Wasserorganismen) sowie dem Verhalten in Kläranlagen werden insgesamt sechs Bewertungszahlen generiert, die auf einer Skala von 1 (vernachlässigbar) bis 5 (sehr hoch) das gesamte Gefährdungsprofil des Stoffes beschreiben sollen. Das Gefährdungsprofil eines Handelsproduktes errechnet sich aus den Gefährdungsprofilen der darin enthaltenen Wirkstoffe anhand eines Algorithmus: Dabei wird die Annahme getroffen, dass die Produkteigenschaften von der Konzentration der darin enthaltenen Wirkstoffe abhängen. Bei der Bewertung ist außerdem zu gewährleisten, dass ein Wirkstoff mit einem hohen Gefährdungspotenzial angemessen berücksichtigt wird, auch und gerade wenn seine Konzentration im Produkt gering ist. In der Literatur wird dazu eine logarithmische Skalierung vorgeschlagen. Die Bewertung berücksichtigt derzeit die Wirkstoffe sowie Anwendungsverdünnungen. Die Zusammenfassung der Produkte in Verwendungs- bzw. Expositionskategorien ermöglicht letztlich eine vergleichende Bewertung. Da das Bewertungsraster gerade auf eine vergleichende Bewertung von Produkten abzielt, unterliegt er einer ständigen kritischen Diskussion, die auch häufig von den Herstellern geführt wird. Dieser Umstand sowie das Faktum von Produktlebenszyklen erfordern ein ständiges Update der in der Datenbank enthaltenen Informationen und eine Anpassung des Bewertungsmodells an den aktuellen Stand von Forschung sowie Standards der Stoff- und Produktpolitik.
Durum wheat is mainly grown as a summer crop. An introduction of a winter form failed until now due to the difficulty to combine winter hardiness with required process quality. Winter hardiness is a complex trait, but in most regions the frost tolerance is decisive. Thereby a major QTL, which was found in T. monococcum, T.aestivum, H. vulgare and S.cereale on chromosome 5, seems especially important. With genotyping by sequencing it is now possible to make association mapping based on very high dense marker maps, which delivers new possibilities to detect main and epistatic effects. Furthermore, new sequencing techniques allow candidate gene based association mapping. The main aim of the project is to unravel the genetic architecture of frost tolerance and quality traits in durum. Thereby, the objectives are to (1) determine the genetic variance, heritability and correlations among frost tolerance and quality traits, (2) examine linkage disequilibrium and population structure, (3) investigate sequence polymorphism at candidate genes for frost tolerance, and (4) perform candidate gene based and genome wide association mapping.
The soil fauna affects soil structure, nutrient mineralization, decomposition processes, and the activity and composition of the microbial community in soil. These effects likely also modify plant performance, plant competition and the use of plant tissue by above-ground herbivores. The proposed project investigates effects of earthworms and soil insects on the above-ground system in grassland communities of different diversity. Earthworm and soil insect density is manipulated in experimental plots differing in plant diversity. The manipulations include the combined exclusion of below-ground insects and above-ground herbivores. It is expected that the response of the above-ground plant and animal community to manipulations of soil animal populations depends on plant species, plant diversity and plant functional group. The differential response is expected to propagate into the herbivore system thereby affecting the structure of the above-ground animal community.
Im Rahmen des Forschungsvorhabens werden Untersuchungen zum Vorkommen der genannten Verbindungen und ihr Verhalten in der Nahrungskette (Carry Over von Futtermitteln fuer Milchtiere in die Milch u.ae.) durchgefuehrt.
On 18 Januar 1986 at the east-looking slope of the Kleiner Watzmann in the Berchtesgaden National Park a snow avalanche came down from an elevation of about 2.000 m to the Königssee near St. Bartholomae (610 m above see level). It destroyed 12 to 15 ha of old growth forests dominated by beech (Fagus sylvatica); about 2.000 m3 of wood were thrown down. The soil survace was not intensively effected by the snow avalange. Because the area is situated in the central protection zone of the national park no clearing procedure was done, and a free stand develeopment without any direct impact of man is allowed to take place. In 1989 permanent plots (3 transects, each starting in the surrounding forest and crossing to avalanche area) were established. Vegetation and stand structure records were carried out in 1989, 1994 and 1999. Vegetation development in the first place is characterised by (1) a re-establishment of the tree layer by the (beech) trees, which were bent to the ground but not killed by the avalanche, (2) by seedling and sapling establishment (especially Acer and Fraxinus, but not by pioneer trees) and (3) by continuing floristic composition of the ground vegetation (coverage increasing or decresing depending on the light conditions).
Bamboos (Poaceae) are widespread in tropical and subtropical forests. Particularly in Asia, bamboos are cultivated by smallholders and increasingly in large plantations. In contrast to trees, reliable assessments of water use characteristics for bamboo are very scarce. Recently we tested a set of methods for assessing bamboo water use and obtained first results. Objectives of the proposed project are (1) to further test and develop the methods, (2) to compare the water use of different bamboo species, (3) to analyze the water use to bamboo size relationship across species, and (4) to assess effects of bamboo culm density on the stand-level transpiration. The study shall be conducted in South China where bamboos are very abundant. It is planned to work in a common garden (method testing), a botanical garden (species comparison, water use to size relationship), and on-farm (effects of culm density). Method testing will include a variety of approaches (thermal dissipation probes, stem heat balance, deuterium tracing and gravimetry), whereas subsequent steps will be based on thermal methods. The results may contribute to an improved understanding of bamboo water use characteristics and a more appropriate management of bamboo with respect to water resources.
Perennial fodder cropping potentially increases subsoil biopore density by formation of extensive root systems and temporary soil rest. We will quantify root length density, earthworm abundance and biopore size classes after Medicago sativa, Cichorium intybus and Festuca arundinacea grown for 1, 2 and 3 years respectively in the applied research unit's Central Field Trial (CeFiT) which is established and maintained by our working group. Shoot parameters including transpiration, gas exchange and chlorophyll fluorescence will frequently be recorded. Precrop effects on oilseed rape and cereals will be quantified with regard to crop yield, nutrient transfer and H2-release. The soil associated with biopores (i.e. the driloshpere) is generally rich in nutrients as compared to the bulk soil and is therefore supposed to be a potential hot spot for nutrient acquisition. However, contact areas between roots and the pore wall have been reported to be low. It is still unclear to which extent the nutrients present in the drilosphere are used and which potential relevance subsoil biopores may have for the nutrient supply of crops. We will use a flexible videoscope to determine the root-soil contact in biopores. Nitrogen input into the drilosphere by earthworms and potential re-uptake of nitrogen from the drilosphere by subsequent crops with different rooting systems (oilseed rape vs. cereals) will be quantified using 15N as a tracer.
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