In structured soils, the interaction of percolating water and reactive solutes with the soil matrix is mostly restricted to the surfaces of preferential flow paths. Flow paths, i.e., macropores, are formed by worm burrows, decayed root channels, cracks, and inter-aggregate spaces. While biopores are covered by earthworm casts and mucilage or by root residues, aggregates and cracks are often coated by soil organic matter (SOM), oxides, and clay minerals especially in the clay illuviation horizons of Luvisols. The SOM as well as the clay mineral composition and concentration strongly determine the wettability and sorption capacity of the coatings and thus control water and solute movement as well as the mass exchange between the preferential flow paths and the soil matrix. The objective of this proposal is the quantitative description of the small-scale distribution of physicochemical properties of intact structural surfaces and flow path surfaces and of their distribution in the soil volume. Samples of Bt horizons of Luvisols from Loess will be compared with those from glacial till. At intact structural surfaces prepared from soil clods, the spatial distribution (mm-scale) of SOM and clay mineral composition will be characterized with DRIFT (Diffuse reflectance infrared Fourier transform) spectroscopy using a self-developed mapping technique. For samples manually separated from coated surfaces and biopore walls, the contents of organic carbon (Corg) and the cation exchange capacity (CEC) will be analyzed and related to the intensities of specific signals in DRIFT spectra using Partial Least Square Regression (PLSR) analysis. The signal intensities of the DRIFT mapping spectra will be used to quantify the spatial distribution of Corg and CEC at these structural surfaces. The DRIFT mapping data will also be used for qualitatively characterizing the small scale distribution of the recalcitrance, humification, and microbial activity of the SOM from structural surfaces. The clay mineral composition of defined surface regions will be characterized by combining DRIFT spectroscopic with X-ray diffractometric analysis of manually separated samples. Subsequently, the spatial distribution of the clay mineral composition at structural surfaces will be determined from the intensities of clay mineral-specific signals in the DRIFT mapping spectra and exemplarily compared to scanning electron microscopic and infrared microscopic analysis of thin sections and thin polished micro-sections. The three-dimensional spatial distribution of the total structural surfaces in the volume of the Bt horizons will be quantified using X-ray computed tomography (CT) analysis of soil cores. The active preferential flow paths will be visualized and quantified by field tracer experiments. These CT and tracer data will be used to transfer the properties of the structural surfaces characterized by DRIFT mapping onto the active preferential flow paths in the Bt horizons.
Die Gesamtfilterwirkung ist ein Kennwert zur Bewertung des Bodens als Filter für sorbierbare Stoffe und wird über das mechanische und physiko-chemische Filtervermögen bewertet. Unter sorbierbare Stoffe fallen insbesondere Stoffgruppen wie die Kationen der Nährstoffe, Schwermetalle und Organika, die entweder im Bodenwasser gelöst sind oder an kleinen Partikeln haften bzw. selbst in Partikelform vorliegen. In gelöster Form werden die genannten Stoffe an den Austauschern (Bodenmaterial) gebunden und so der Bodenlösung entzogen. In Partikelform werden sie im Boden gefiltert, wenn sie aufgrund mechanischer Hindernisse, wie z. B. am Ende von Wurmröhren, mit dem Sickerwasser nicht mehr weiter transportiert werden können. Die Gesamtfilterwirkung kann in Abhängigkeit von der Kationenaustauschkapazität und der Luftkapazität geschätzt werden. Das Schätzergebnis besteht aus insgesamt 11 Stufen, von denen in Schleswig-Holstein nur 8 relevant sind. Je höher die Stufe ist, desto höher ist die Gesamtfilterwirkung. Sie ist in feinkörnigem Bodenmaterial mit geringer Luftkapazität am größten, wie z. B. in der Marsch und im Östlichen Hügelland, und in grobkörnigem Bodenmaterial mit hoher Luftkapazität am geringsten, wie z. B. in der Vorgeest. Mit der Gesamtfilterwirkung wird eine natürliche Bodenfunktionen nach § 2 Abs. 2 BBodSchG bewertet und zwar nach Punkt 1.c) als Abbau-, Ausgleichs- und Aufbaumedium für stoffliche Einwirkungen auf Grund der Filter-, Puffer- und Stoffumwandlungseigenschaften, insbesondere auch zum Schutz des Grundwassers. Das hierfür gewählte Kriterium ist das mechanische und physiko-chemische Filtervermögen des Bodens mit dem Kennwert Gesamtfilterwirkung. Die Karten liegen für die folgenden Maßstabsebenen vor: - 1 : 1.000 - 10.000 für hochaufgelöste oder parzellenscharfe Planung, - 1 : 10.001 - 35.000 für Planungen auf Gemeindeebene, - 1 : 35.001 - 100.000 für Planungen in größeren Regionen, - 1 : 100.001 - 350.000 für landesweit differenzierte Planung, - 1 : 350.001 - 1000.000 für landesweite bis bundesweite Planung.
Background: An increasing frequency of massive flooding along the lower Yangtse River in China ended in a disastrous catastrophe in summer 1998 leaving several thousand people homeless, more than 3.600 dead and causing enormous economic damage. Inappropriate land-use techniques and large scale timber felling in the water catchment of the upper Yangtse and its feeder streams were stated to be the main causes. Immediate timber cutting bans were imposed and investigations on land use patterns were initiated by the Chinese Government. The Institute for World Forestry of the Federal Research Centre for Forestry and Forest Products was approached by the Yunnan Academy of Forestry in Kunming to exchange experiences and to cooperate scientifically in the design and application of appropriate afforestation and silvicultural management techniques in the water catchment area of the Yangtse. This cooperation was initiated in 1999 and is based on formal agreements in the fields of agrarian research between the German and Chinese Governments. Objectives: The cooperation was in the first step focussing on the identification of factors which caused the enormous floodings. After their identification measures of prevention were determined and put into practice. In this context experiences made in past centuries in the alpine region of central Europe served as an incentive and example for similar environmental problems and solutions under comparable conditions. Relevant key questions of the cooperation project were: - Analysis of forest related factors influencing the recent floodings of the Yangtse, - Analysis and evaluation of silvicultural management experiences from central Europe for know-how transfer, - Evaluation of rehabilitation measures for successful application in Yunnan, - Dissemination of knowledge through vocational training. Results: - Frequent wild grazing of husbandry is a key factor for forest degeneration beyond unsustainable timber harvests, forest fires and insect calamities leading to increased water run-off in the mountainous region of Yunnan; - Browsing of cattle interrupts succession thus avoiding natural regeneration and leaving a logging ban ineffective; - Mountain pasture in the Alps had similar effects in the past in central Europe. The introduction of controlled grazing has led to an ecologically compatible coexistence of pasture and ecology. Close-to-nature forestry can have positive effects in this sensitive environment. - Afforestation with site adopted broadleaves and coniferous tree species was implemented on demonstration level using advanced techniques in Yunnan.
Various species of pest insects cause substantial damage to agriculture every year, or transmit deadly diseases to animals and humans. A successful strategy to control pest insect populations is based on the Sterile Insect Technique (SIT), which uses the release of mass-reared, radiation sterilized male insects to cause infertile matings and thus reduce the pest population level. However, irradiation is not applicable to every insect species. Thus, new strategies based on genetic modifications of pest insects have been developed or are currently under investigation.The goal of the proposed research is to improve the development and ecological safety of genetically engineered (GE) insects created for enhanced biological control programs, including the SIT and new strategies based on conditional lethality. A major concern for GE insect release programs is transgene stability, and maintenance of their consistent expression. Transgene loss or intra-genomic movement could result in loss of strain attributes, and may ultimately lead to interspecies movement resulting in ecological risks. To address potential transgene instability, a new transposon vector that allows post-integration immobilization will be tested in the Mediterranean, Mexican and Oriental fruit fly tephritid pest species. In addition, the system will be established in the mosquito species Aedes and Anopheles - carriers of dengue and malaria.Random genomic insertion is also problematic for GE strain development due to genomic position effects that suppress transgene expression, and insertional mutations that negatively affect host fitness and viability. Diminished transgene expression could result in the unintended survival of conditional lethal individuals, or the inability to identify them. To target transgene vectors to defined genomic insertion sites having minimal negative effects on gene expression and host fitness, a recombinase-mediated cassette exchange (RMCE) strategy will be developed that. RMCE will also allow for stabilization of the target site, will be tested in tephritid and mosquito species, and will aid to the development of stabilized target-site strains for conditional lethal biocontrol. This will include a molecular and organismal evaluation of an RNAi-based lethality approach. Lethality based on an RNAi mechanism in the proposed insects would increase the species specificity and having multiple targets for lethality versus one target in existing systems. By seeking to improve transgene expressivity and stabilization of transposon-based vector systems, this proposal specifically addresses issues related to new GE insects by reducing their unintended spread after field release, and by limiting the possibilities for transgene introgression.
EAGER is a core group of international scientists trying to improve and harmonize national ammonia emission inventory calculations. Through the exchange they strive to continuously improve their respective N flux models. Six N-flow models used to calculate NH3 emissions from agriculture for inventories and policy implementation in UK, DK, NL, DE, CH were compared using standard activity data sets. For liquid manure the results were well comparable. For solid manure larger differences indicated greater uncertainties. In a third WP a survey on punlished and unpulished experimental data on emissions from solid manure was therfore conducted. Project goal: EAGER aims at achieving a detailed overview of the present best available inventory techniques, compiling and harmonizing the available knowledge on emission factors (EF) and initiating a new generation of NH3 emission inventories. Results: EAGER is a core group of international scientists trying to improve and harmonize national ammonia emission inventory calculations. Through the exchange they strive to continuously improve their respective N flux models
In coastal and marginal seas with stable stratification and reduced water exchange, hypoxic deep-water conditions are a frequently observed phenomenon. The so-called redoxcline, developing under such conditions at the top of the anoxic layer, is characterized by strong biogeochemical gradients, which are the location of some important microbially mediated element transformations. Here, our project hypothesis is that the rapid and intermittent modification of the local biogeochemical and microbiological conditions associated with lateral intrusions, in particular due to turbulent mixing between intrusions and ambient waters, constitutes an essential component of the redoxcline system. We plan to study this link between hydrography, turbulent mixing, biogeochemical processes, and microbial activities, taking the central Baltic Sea with its well-defined redoxcline as an example. A recently established autonomous profiling system in the Central Baltic Sea will provide high-resolution data, allowing us to determine the long-term variability of hydrographic, biogeochemical, and mixing parameters associated with the intrusions. The impact of mixing for the microbial activities and communities will be investigated during ship cruises, combining observations of mixing parameters, and representative biogeochemical and microbial transformation processes.
The main topic in the current phase of our project concerns the mycorrhiza (Greek for 'fungus-root'), arguably the most common but still largely enigmatic mutualistic symbiosis on land fulfilling a key role in terrestrial ecosystems: it is responsible for establishing the basic linkage of the plants as the primary producers of the biosphere to the soil and bedrock of the pedo- and lithosphere. In this symbiosis, the mycorrhizal fungi spread out in the soil with an intricate mycelial network, foraging for nutrients that are delivered to their plant partners in exchange for products of photosynthesis. These extended networks belowground exert also many other key functions for maintaining natural soil fertility such as preventing losses in the process of nutrient cycling, stabilization of soil structure counteracting erosion and sequestration of carbon in the soil. The mycorrhizal networks are known also to form linkages between roots of different plants. Currently our main interest is to explore interactions between such interconnected plants. Using isotope tracer techniques, we measure the investments of co-existing plants for the build-up and maintenance of common mycorrhizal networks and conversely, the return of these investments by the gain of mineral nutrients via these networks. We found that the returns of investments in shared networks are not necessarily balanced, with plants contributing much but profiting little and vice versa. We are particularly interested in the functioning of mycorrhizal networks shared between plants belonging to different functional groups (e.g. grasses, legumes etc.) where mutual facilitation has been observed. Moreover we want to assess the capability of plants to integrate in preformed mycorrhizal networks (e.g. seedlings, invasive plants, annual crops in agro-forestry and mixed-cropping systems) and to select the fungal species most awarding for them as symbiotic partner when exposed to diverse fungal communities. To tackle such questions, we developed new molecular tools allowing a specific tracing of individual fungal strains in colonized roots. These techniques are of relevance also in the current endeavor to develop more sustainable agricultural systems demanding less input of mineral fertilizers by the use of mycorrhizal fungi as 'bio-fertilizers'.
Landscape changes may influence population persistence and genetic diversity of black-backed Swamphen (Porphyrio indicus) in Java Island. The changes occurred rapidly, particularly in the coastal area, due to human population pressure. It may affect negatively the quality and compactness of natural ecosystems, particularly wetlands. In turn, it may lead to a reduction of critical resources and impair individual movement. The effect will be severe particularly for wetland-breeding specialist with poor flight capability like in black-backed Swamphen. It is reasonable that some local ornithologist warn about the bird species persistence. Limited information on its behavior and biology make the conservation efforts even more difficult. The species cryptic behavior impedes direct observation for habitat and movement studies, whereas fraught classification makes information on their population size and distribution debatable. Limited reliable information on these aspects may pose an obstacle to conserve their natural population in a rapidly changed environment. Information on population structure and the individual movement between sub populations are central for species conservation in a changing landscape. The project will address some important questions about the effect of the changes on population isolation and its suspected causes, rate of dispersal necessary to maintain genetic diversity, and biased dispersal. A new approach combining molecular genetic and GIS techniques may provide such information and may overcome the lack of direct observations. As guidance for data collection and analysis, general research question is defined as follows: 'How do landscape feature influence individual movement between population of Porphyrio indicus in Java Island ?' Following it, some sub questions may arise: What are the landscape structure and composition in past and recent years? How populations are spatially structured in recent and past years? Is there any evidence of individual exchange between subpopulations? Which landscape features are supposed to facilitate and inhibit individual exchange? Which landscape features do explain population structure better? Several work steps are planned: field work for collecting genetic material, laboratory work for isolation-amplification-analysis of DNA fragments, and desk work for landscape analysis. Raw genetic data of and landscape features will be combined to address the research questions.
Climate projections and trend analysis of historical data suggest that precipitation and temperature changes can dramatically alter the supply of and the demand for water in the human- and eco-systems. Moreover, anthropogenic landscape changes are occurring at unprecedented scales and rates given the societal needs for various (and often competing) ecosystem goods and services (food, energy, and water). How stable or resilient are the human- and eco- systems to climatic and anthropogenic perturbations remain a major societal concern. Of these concerns, hydrologic cycle changes, water resources availability and related management rank among the highest because of their importance in regulating human and ecological sustainability and climate feedbacks. A number of recent studies suggest that continental runoff increased throughout the 20th century despite a rapid increase in water consumption by humans and their activities. Scope of the project: The goal of this research program is on the overall impact of such changes on rainfall (the source of water) and concomitant replenishment of usable water supplies (e.g. ground- and stream- water) given their high priority to any future water resource planning. Even within this restricted scope, the barriers to scientific progress are numerous necessitating an inter-disciplinary approach that combines principles from eco-hydrology, hydraulics and fluid mechanics, soil physics, plant physiology, stochastic processes, dynamical systems theory, and water resources management. This project aims to build a network of researchers with complementary talents to begin progress on these fronts. Moreover, this network of researchers will be actively engaged in preparing the next generation of international scientists (via graduate student exchanges) who will be trained to approach such interdisciplinary societal problems and progress on them by adopting trans-disciplinary approaches now emerging from complex systems science.