Das Projekt "Significance of xylem translocated sulfate in early responses of stomata to drought in poplar plants" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Institut für Forstbotanik und Baumphysiologie durchgeführt. Water deficiency, sensed by the root, is supposed to be signaled via xylem transport from the root to the shoot by chemical as well as hydraulic signals. In response to these signals stomatal conductance is reduced to prevent excessive water loss. The chemical signal mostly responsible for stomatal closure in response to drought is thought to be the photohormone abscisic acid (ABA). However, the origin of the ABA involved in this process is still a matter of debate, since it can be synthesized in roots and the shoot. Recent experiments indicated that increasing sulfate con-centrations in the xylem constitute an early response to drought; therefore, it has been hypothesized that xylem-borne sulfate accelerates the ABA signal for stomatal closure and that enhanced ABA in the leaves in response to drought does not necessarily originate from synthesis in roots; acceleration of stomatal closure by sulfate is thought to be achieved by activating malate efflux channels of guard cells. To test this hypothesis, (i) mass transport of ABA and sulfate in the xylem, (ii) its sources and the sinks during drought, (iii) drought mediated regulation of expression of sulfate transporters / anion channels, and (iv) the effects of sulfate and ABA on malate efflux from isolated guard cells will be studied. Experiments will be performed with wild type and transgenic poplar lines with altered expression of sulfate transporters, enhanced sulfate use for reduction, and in ABA insensitive mutants.
Das Projekt "Water yield response to changes in land-use and climate in a semihumid/-arid transition region (Jinghe basin, Northwest China)" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Institut für Bodenkunde und Standortslehre durchgeführt. The effort of vegetation restoration in recent decades has been effective for soil erosion control, but accompanied by a drastic reduction of water yield in the main tributaries of the Yellow River. This has led to an emerging debate notably about forest development. Increased temperature and decreased precipitation may also have contributed to water yield reduction. An essential key for developing an integrated land-use and water management approach is to understand and separate the hydrological response to changes in land use and climate. In this study on multiple scales ranging from single tree to watershed, water balance components, vegetation structure dynamics, and soil hydraulic properties will be investigated and continuously monitored on selected plots with vegetation typical to the region. Our research will be carried out in the semihumid/-arid transition region of Jinghe which is an important tributary of the Yellow River. We follow a nested approach on scales of plots and watersheds along a upstream/downstream situation in a representative subbasin. On the basis of our measurements, the process-oriented model BROOK90 will be implemented for predicting the water yield response to changes in climate and vegetation depending on relief and soil conditions. The results obtained from plot studies will be used to parameterize the distributed model SWIM. In a next step, SWIM will be fitted to the catchment discharge and to assess the effect of different land use and vegetation management on water yield. This assessment will provide a solid foundation for how much of the catchment area can be changed by vegetation restoration through forest management to maintain a certain level of water supply security that will ensure a more sustainable regional development.
Das Projekt "E 2.2: Contributions of expanded raw material availability and waste utilization to sustainable fruit processing in the tropics and subtropics" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Lebensmittelwissenschaft und Biotechnologie, Fachgebiet Lebensmittel pflanzlicher Herkunft (150d) durchgeführt. Since the beginning of the Uplands Program in 2000, subproject E2 has been aimed at adjusted strategies for the utilization of mangoes, lychees and longans. The whole processing chain from fruit production through fruit processing to marketing has been studied in an interdisciplinary approach together with subprojects D1.1 (Fruit production) and E3.1 (Market potential) in Thailand. Various levels, such as raw material quality as well as technological and economic evaluation of fruit processing, have been investigated. In fruit processing, technological focus has been on fluid mango products. Continuation of E2 in phase 2 of the Uplands Program aims at sustainable food processing on two levels. Regarding quality profiles of raw fruits for fresh marketing or processing, quality and food safety aspects of fruits produced out of season is in the center of attention, since increased capacity utilization is expected due to increase or extension of harvesting periods per year, which should be based on ecologically compatible fruit production. Continuing research on mango processing, material circulation in food processing is intended by utilization of waste from fruit processing to recover by-products, especially pectins as gelling and stabilizing agents or bioactive fiber, prior to the use of residual waste as feed, thus reducing disposal problems and increasing added value by processing of the whole raw material into high-value main and by-products. Investigating the long-term effects of present and new off-season fruit production techniques applied by D1.1-2 (Alternate bearing) on fruit yield and quality in terms of appearance, basic components such as soluble solids, titratable acidity, vitamins and selected secondary plant metabolites (polyphenols), E2.2 is involved in the interdisciplinary research on the potential of off-season fruit production. Present public discussion on food safety, which is caused by increasing export problems due to exessive use of agrochemicals in Thailand, requires to test the effect of long-term application of paclobutrazol (PBZ) and KClO3. Both agrochemicals are presently used in root treatment of mango and longan trees, respectively, to induce flowering and off-season fruit production. Quantitative residue analyses in fruits will be performed by E2.2 applying GC-MS and HPLC. Conflicting reports on PBZ mobility in the plant support the need to prove the absence of non-tolerable PBZ residues in off-season mango fruits, thus strengthening the objective of D1.2 (Alternate bearing) in replacement of PBZ. Together with B2.2 (Agrochemical transport), residue analysis in the soil will be performed for the highly persistent triazolic plant growth regulator PBZ to monitor the impact of long-term application of PBZ on environmental risks in present off-season fruit production techniques over the period of phase 2. (abridged text)
Das Projekt "SP 1.2 Optimisation of soil organic matter management under intensive cropping in the North China Plain" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. Intensive maize-wheat double cropping is a common plant production system at the North China Plains. More than 600 kg N/ha as mineral N fertiliser are applied annually while only 300 to 350 kg N/ha are removed with plant products. Despite of this extraordinarily high level of N-fertilisation, the yield potential in the common wheat-maize cropping system is by far not fully taped yet. Beside low N utilization efficiencies (partly less than 30 percent), frequent lodging and environmental pollution including leaching and gaseous losses of N are the results of the excessive use of fertiliser-N. Within this study, different N-fertilisation, tillage and cropping strategies shall be investigated with their potential to maintain high levels of SOM and to guaranty high and stable yields in the long term in the North China Plain. Future developments like climate change and increasing demand for energy production from plant residues shall be considered. Special emphasis will be put on the fate of (fertilised) N which preferably should be available for plant uptake and built up of organic matter but may also disappear by leaching and gaseous losses. A combination of lab experiments, existing and newly established long term field experiments combined with computer modelling shall be used to extrapolate short and medium term findings into the future and up to a regional scale.
Das Projekt "Impact of long-term exposure to elevated pCO2 on activity and populations of free living N2 fixing organisms in a temperate grassland system" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Tropische Agrarwissenschaften (Hans-Ruthenberg-Institut), Fachgebiet Pflanzenbau in den Tropen und Subtropen (490e) durchgeführt. The project aims at achieving a better understanding of the processes that drive or limit the response of grassland systems in a world of increasing atmospheric pCO2. We will test the hypothesis that the previously shown increase in below-ground allocation of C under elevated pCO2 provides the necessary energy excess and will stimulate free-living N2 fixers in a low N grassland environment. The project thus aims at assessing the occurrence and importance of free-living N2 fixers under elevated pCO2 and identify the associated microbial communities involved in order to better understand ecosystems response and sustainability of grassland systems. This project had the last opportunity to obtain soil samples from a grassland ecosystem adapted to long-term (10 year) elevated atmospheric pCO2 as the Swiss FACE experiment. The project aims to identify the relevant components of free-living diazotrophs of the microbial community using 15N stable isotope - DNA probing.
Das Projekt "The European aeroemissions network (AERONET)" wird vom Umweltbundesamt gefördert und von Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut für Antriebstechnik durchgeführt. One of the major problems that civil aeronautics will have to face over the next twenty or thirty years is to accommodate the predicted growth in demand of air transport without creating unacceptable adverse environmental effects. It is to be expected that new scientific results, increasing public concerns over the environment and future restrictive regulations with respect to aircraft emissions will force airline companies to take ecological considerations much more into account than it does at present. Consequently, for European aircraft manufacturers it is of high importance to react early and to guide their research and development resources into the most important and efficient direction. The aim of the AERONET project is to support coordination ' a postiori' of existing European and national projects or programmes dealing with the contribution of air traffic emissions to anthropogenic climate and atmospheric changes. For this purpose AERONET seeks to : - bring together experts from engine technology, atmospheric research and operations as well as programme responsible to exchange knowledge and opinions and to discuss necessary future actions on the basis of jointly defined goals and time scales, - produce competitive advantage for Europe through enhanced information echoing in the field of atmospheric effects of air traffic emissions, - strengthen a common European position in global technical and political discussions - support the Commission in identifying topics for the 5th Framework Programme, - identify gaps and help prepare a coordinated submission of proposals. European Dimension and Partnership: Europe is, beside the US, one of the two biggest aircraft manufacturers. One supposition for the economic success of European aircraft industry is not only to fulfill the existing regulations but, due to the long development times of 5-10 years and the long lifetimes of aircraft of more than 20 years, also to take the trend of future regulations development into account at a very early stage. This needs continuous and fast information exchange and discussions between atmospheric scientists, aircraft engineers and regulatory organisations. To be successful with an effort of this dimension, optimal coordination of national and European programmes in all three fields is required. Thus the network brings together representatives of all programmes and institutions concerned, helps to integrate activities through better information exchange, tries to identify the most urgent themes for R&D activities and intends to give recommendations for the Fifth Framework Programme. Potential Applications: Understanding the atmospheric impacts, the technical consequences and development perspectives, and the operational impacts as a whole is absolutely necessary to strengthen the European position in global regulatory committees on the on side and to gain competitive advantages for the European aircraft and airline industries on the other side. usw
Das Projekt "Steady-State Dilution and Mixing-Controlled Reactions in Three-Dimensional Heterogeneous Porous" wird vom Umweltbundesamt gefördert und von Eberhard Karls Universität Tübingen, Zentrum für Angewandte Geowissenschaften (ZAG), Arbeitsgruppe Hydrogeology durchgeführt. Understanding transport of contaminants is fundamental for the management of groundwater re-sources and the implementation of remedial strategies. In particular, mixing processes in saturated porous media play a pivotal role in determining the fate and transport of chemicals released in the subsurface. In fact, many abiotic and biological reactions in contaminated aquifers are limited by the availability of reaction partners. Under steady-state flow and transport conditions, dissolved reactants come into contact only through transverse mixing. In homogeneous porous media, transverse mixing is determined by diffusion and pore-scale dispersion, while in heterogeneous formations these local mixing processes are enhanced. Recent studies investigated the enhancement of transverse mixing due to the presence of heterogeneities in two-dimensional systems. Here, mixing enhancement can solely be attributed to flow focusing within high-permeability inclusions. In the proposed work, we will investigate mixing processes in three dimensions using high-resolution laboratory bench-scale experiments and advanced modeling techniques. The objective of the proposed research is to quantitatively assess how 3-D heterogeneity and anisotropy of hydraulic conductivity affect mixing processes via (i) flow focusing and de-focusing, (ii) increase of the plume surface, (iii) twisting and intertwining of streamlines and (iv) compound-specific diffusive/dispersive properties of the solute species undergoing transport. The results of the experimental and modeling investigation will allow us to identify effective large-scale parameters useful for a correct description of conservative and reactive mixing at field scales allowing to explain discrepancies between field observations, bench-scale experiments and current stochastic theory.
Das Projekt "Mycorrhizal response and nutrient uptake of old, new and organically bred winter wheat cultivars in low input systems" wird vom Umweltbundesamt gefördert und von Forschungsinstitut für Biologischen Landbau durchgeführt. The testing of crop cultivars on organic and conventional farms is often confounded by site heterogeneity. We compared the performance of a set of old, conventionally and organically bred winter wheat (Triticum aestivum L.) cultivars within the DOK long term trial in CH-Therwil in 2007. In the DOK trial organic and conventional farming systems are compared since 1978 in a split-split plot design with four replicates on a haplic luvisol. Yield (dry matter yield, thousand kernel weight, harvest index and nitrogen harvest index) and quality parameters (grain protein content, Hagberg falling number, Zeleny value, wet gluten content and gluten index) of ten cultivars were assessed in four systems: unfertilized control (NOFERT), bio-dynamic (BIODYN 1 and 2) and one conventional farming system (CONMIN) with different levels of total nitrogen inputs (0, 33, 66 and 140 kg ha-1, respectively). Effects of cultivars and systems on yield and quality parameters were statistically significant, genotype x system interactions were generally not detected. Grain yield increased from 2.7 (NOFERT), 3.7 (BIODYN 1), 4.2 (BIODYN 2) up to 6.8 t ha-1 for the conventional system CONMIN with an average protein content of 10.8, 9.4, 9.0 and 11.7%, respectively. No significant differences between cultivars were detected for yield in the organic system BIODYN 2, whereas in the conventional system CONMIN, cultivars bred under conventional conditions yielded significantly more than old cultivars. However, the protein content of old cultivars was significantly higher than that of modern cultivars. The results imply that breeding for yield was successful during the last century but only under high input conditions (7.6 kg ha-1 yr-1 in the conventional system CONMIN), where the development was accompanied by rising inputs of external resources (e.g. mineral fertilizers). Under organic conditions, yield increase with the year of release of cultivars was only 1.8 kg ha-1 yr-1 (in the organic system BIODYN 2) and modern cultivars could not outperform the old cultivars, irrespective of their selection environment. A redundancy analysis showed that yield was mainly determined by systems or the input of fertilizers, while the influence of cultivars was only minor. The redundancy analysis for baking quality parameters in contrast revealed that the influence of cultivars was higher than the influence of the systems. It is suggested, that long term system comparisons can ideally serve to test crop cultivars under identical soil and climatic conditions. Root colonization with arbuscular mycorrhizal fungi (AMF) was higher under organic than under conventional farming conditions but there was no evidence that breeding conditions were influencing AMF-root colonization of the different cultivars. We observed a positive correlation for AMF root colonization and shoot P at tillering and flowering under organic but not under conventional conditions. (abridged text)
Das Projekt "Flood risk in a changing climate (CEDIM)" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Meteorologie und Klimaforschung, Department Troposphärenforschung durchgeführt. Aims: Floods in small and medium-sized river catchments have often been a focus of attention in the past. In contrast to large rivers like the Rhine, the Elbe or the Danube, discharge can increase very rapidly in such catchments; we are thus confronted with a high damage potential combined with almost no time for advance warning. Since the heavy precipitation events causing such floods are often spatially very limited, they are difficult to forecast; long-term provision is therefore an important task, which makes it necessary to identify vulnerable regions and to develop prevention measures. For that purpose, one needs to know how the frequency and the intensity of floods will develop in the future, especially in the near future, i.e. the next few decades. Besides providing such prognoses, an important goal of this project was also to quantify their uncertainty. Method: These questions were studied by a team of meteorologists and hydrologists from KIT and GFZ. They simulated the natural chain 'large-scale weather - regional precipitation - catchment discharge' by a model chain 'global climate model (GCM) - regional climate model (RCM) - hydrological model (HM)'. As a novel feature, we performed so-called ensemble simulations in order to estimate the range of possible results, i.e. the uncertainty: we used two GCMs with different realizations, two RCMs and three HMs. The ensemble method, which is quite standard in physics, engineering and recently also in weather forecasting has hitherto rarely been used in regional climate modeling due to the very high computational demands. In our study, the demand was even higher due to the high spatial resolution (7 km by 7 km) we used; presently, regional studies use considerably larger grid boxes of about 100 km2. However, our study shows that a high resolution is necessary for a realistic simulation of the small-scale rainfall patterns and intensities. This combination of high resolution and an ensemble using results from global, regional and hydrological models is unique. Results: By way of example, we considered the low-mountain range rivers Mulde and Ruhr and the more alpine Ammer river in this study, all of which had severe flood events in the past. Our study confirms that heavy precipitation events will occur more frequently in the future. Does this also entail an increased flood risk? Our results indicate that in any case, the risk will not decrease. However, each catchment reacts differently, and different models may produce different precipitation and runoff regimes, emphasizing the need of ensemble studies. A statistically significant increase of floods is expected for the river Ruhr in winter and in summer. For the river Mulde, we observe a slight increase of floods during summer and autumn, and for the river Ammer a slight decrease in summer and a slight increase in winter.
Das Projekt "F 2.2: Risk management of farm households in Northern Vietnam" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Agrar- und Sozialökonomie in den Tropen und Subtropen durchgeführt. Sub-project F2 Rural financial services and sustainable rural development in Northern Vietnam assessed in the 1st phase (July 2000 - June 2003) of the Uplands Program (SFB 564) the conditions of effective financial market functioning in rural Vietnam serving rural economic development with particular emphasis on sustainable agricultural production systems. The sub-project F2-1 analysed the factors that determine access to financial services, particularly credit and savings services, by farm households. The main results of the 1st phase of F2 were threefold. First, the so-called Conjoint Analysis showed that poor rural households are capable and willing to save. Second, the study of the secondary and primary data (118 households in Bac Kan province and 142 households in Son La province) indicated that the two state-owned rural development banks, the Vietnam Bank for the Poor (VBP) and the Vietnam Bank for Agriculture and Rural Development (VBARD) together have already an enormous outreach as it concerns the supply of microcredit. The two banks reach 58Prozent of all rural households in Vietnam. Nevertheless, the microcredit is heavily restricted to specific uses, among the uses being the purchase of livestock, one of the most popular presently. Third, participatory workshops with the farm households revealed that the debtors perceive their livelihood as severely threatened by the risk of failing debt-financed investments and other individual risks. As a consequence to the manifold risks that a rural household is exposed to, the households have adopted risk coping strategies to smooth consumption, nevertheless, adaptive strategies to stabilize income are lacking. This can result in coping strategies focusing on the exploitation of natural resources and human capital resulting in unsustainable livelihoods. Based on these results, the consequent conclusion is that more research is needed regarding the third corner-stone of rural finance in developing countries, which is microinsurance. Acquiring microinsurance counts to the adaptive strategies of vulnerable households. In phase 2 (July 2003 - June 2006) of the Uplands Program, sub-project F2 will therefore concentrate its research on livelihood clusters of vulnerable rural households, and their adaptive and coping strategies regarding risks. While adaptive strategies are ex-ante strategies and aim at secure income even in times of crises, coping strategies are a reaction to acute risks and are employed ex-post. Informal social networks and semi-formal microinsurance schemes count to the former strategies and either keep vulnerability levels constant or even reduce them. The latter strategies try to smooth consumption, nevertheless, often at the expense of the future livelihood, thereby increasing vulnerability. (abridged text)