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Found 570 results.

Establishment of Teak plantations for high-value timber production in Ghana

Background and Objectives: The project area is located in the Ashanti Region of Ghana / West Africa in the transition zone of the moist semideciduous forest and tropical savannah zone. Main land use in this region is subsistence agriculture with large fallow areas. As an alternative land-use, forest plantations are under development by the Ghanaian wood processing company DuPaul Wood Treatment Ltd. Labourers from the surrounding villages are employed as permanent or casual plantation workers. Within three forest plantation projects of approximately 6,000 ha, DuPaul offers an area of 164 ha (referred to as Papasi Plantation) - which is mainly planted with Teak (Tectona grandis) - for research purposes. In return, the company expects consultations to improve the management for sustainable timber and pole production with exotic and native tree species. Results: In a first research approach, the Papasi Plantation was assessed in terms of vegetation classification, timber resources (in qualitative and quantitative terms) and soil and site conditions. A permanent sampling plot system was established to enable long-term monitoring of stand dynamics including observation of stand response to silvicultural treatments. Site conditions are ideally suited for Teak and some stands show exceptionally good growth performances. However, poor weed management and a lack of fire control and silvicultural management led to high mortality and poor growth performance of some stands, resulting in relative low overall growth averages. In a second step, a social baseline study was carried out in the surrounding villages and identified landowner conflicts between some villagers and DuPaul, which could be one reason for the fire damages. However, the study also revealed a general interest for collaboration in agroforestry on DuPaul land on both sides. Thirdly, a silvicultural management concept was elaborated and an improved integration of the rural population into DuPaul's forest plantation projects is already initiated. If landowner conflicts can be solved, the development of forest plantations can contribute significantly to the economic income of rural households while environmental benefits provide long-term opportunities for sustainable development of the region. Funding: GTZ supported PPP-Measure, Foundation

Development of a modelling system for prediction and regulation of livestock waste pollution in the humid tropics

Introduction: In Malaysia, excessive nutrients from livestock waste management systems are currently released to the environment. Particularly, large amounts of manure from intensive pig production areas are being excreted daily and are not being fully utilised. Alternatively, the excess manure can be applied as an organic fertiliser source in neighbouring cropping systems on the small landholdings of the pig farms to improve soil fertility so that its nutrients will be available for crop uptake instead of being discharged into water streams. Thus, there is a need for better tools to analyse the present situation, to evaluate and monitor alternative livestock production systems and manure management scenarios, and to support farmers in the proper management of manure and fertiliser application. Such tools are essential to quantify, and assess nutrient fluxes, manure quality and content, manure storage and application rate to the land as well as its environmental effects. Several computer models of animal waste management systems to assist producers and authorities are now available. However, it is felt that more development is needed to adopt such models to the humid tropics and conditions of Malaysia and other developing countries in the region. Objectives: The aim is to develop a novel model to evaluate nutrient emission scenarios and the impact of livestock waste at the landscape or regional level in humid tropics. The study will link and improve existing models to evaluate emission of N to the atmosphere, and leaching of nutrients to groundwater and surface water. The simulation outputs of the models will be integrated with a GIS spatial analysis to model the distribution of nutrient emission, leaching and appropriate manure application on neighbouring crop lands and as an information and decision support tool for the relevant users.

DFG Trilateral collaboration Deutschland-Israel-Palestine: Nematodes as potential vectors for human pathogens

Outbreaks of foodborne illness linked to consumptions of fresh, or partially processed, agricultural products are a growing concern in industrialized and developing countries. The incidence of human pathogens on fresh fruits and vegetables is often related to the use of recycled wastewaster in surface irrigation as well as high amounts of animal manure in agricultural management practice. Thereby the soil inhabiting fauna plays an important role in the transport and dissemination of microorganisms. The focus of the proposed project is on nematodes, well known vectors for bacteria and viruses in soil. The major goals are to: (1) survey human pathogens in soil and on/in free-living and plant parasitic nematodes in agriculture field sites irrigated with recycled wastewater or fertilized with fresh animal manure in Israel and the Palestinian Authority, (2) assess the function of nematodes as vectors in transmitting bacteria from microbial hot spots to plants, and (3) localize bacteria on and/or within the nematode and identify bacterial factors required for survival in the nematode host. Understanding the mechanisms involved in dissemination of human pathogens by nematodes will enhance the ability to develop practical means to minimize contamination of fresh produce and increase safety in food production.

Can the resistance and resilience of trees to drought be increased through thinning to adapt forests to climate change?

Recent and predicted increases in extremely dry and hot summers emphasise the need for silvicultural approaches to increase the drought tolerance of existing forests in the short-term, before adaptation through species changes may be possible. We aim to investigate whether resistance during droughts, as well as the recovery following drought events (resilience), can be increased by allocating more growing space to individual trees through thinning. Thinning increases access of promoted trees to soil stored water, as long as this is available. However, these trees may also be disadvantaged through a higher transpirational surface, or the increased neighbourhood competition by ground vegetation. To assess whether trees with different growing space differ in drought tolerance, tree discs and cores from thinning experiments of Pinus sylvestris and Pseudotsuga menziesii stands will be used to examine transpirational stress and growth reduction during previous droughts as well as their subsequent recovery. Dendroecology and stable isotopes of carbon and oxygen in tree-rings will be used to quantify how assimilation rate and stomatal conductance were altered through thinning. The results will provide crucial information for the development of short-term silvicultural adaptation strategies to adapt forest ecosystems to climate change. In addition, this study will improve our understanding of the relationship between resistance and resilience of trees in relation to extreme stress events.

Indonesian Throughflow variability on sub-orbital timescales during Marine Isotopes Stages (MIS) 2 and 3

This project will provide quantitative estimates of the flow of low-salinity warm water through the Indonesian Gateway on suborbital timescales during MIS 2 and 3 (focusing on Dansgaard Oeschger (D-O) oscillations) and will assess the Indonesian Throughflow (ITF) s impact on the hydrography of the eastern Indian Ocean and global thermohaline circulation during this critical interval of high climate variability. ITF fluctuations, associated with sea level change, temperature and salinity variations in the West Pacific Warm Pool (WPWP) strongly influence precipitation over Australia, the strength of the southeast-Asian summer monsoon, and the intensity of warm meridional currents in the Indian Ocean. We will test the hypothesis that increased ITF is associated with warm interstadials of MIS 3, whereas a strong reduction in ITF occurred during stadials. We will use as main proxies planktonic and benthic foraminiferal isotopes in conjunction with Mg/Ca temperature estimates and radiogenic isotopes (mainly Nd) as tracers of Pacific water masses along depth transects in the Timor Passage and the eastern Indian Ocean. This project will provide the paleoceanographic framework that will be crucial to validate and refine circulation models of D-O events and high-frequency climate variability on a global scale.

Profiling methane emission in the Baltic Sea: Cryptophane as in-situ chemical sensor

To overcome the limitation in spatial and temporal resolution of methane oceanic measurements, sensors are needed that can autonomously detect CH4-concentrations over longer periods of time. The proposed project is aimed at:- Designing molecular receptors for methane recognition (cryptophane-A and -111) and synthesizing new compounds allowing their introduction in polymeric structure (Task 1; LC, France); - Adapting, calibrating and validating the 2 available optical technologies, one of which serves as the reference sensor, for the in-situ detection and measurements of CH4 in the marine environments (Task 2 and 3; GET, LAAS-OSE, IOW) Boulart et al. (2008) showed that a polymeric filmchanges its bulk refractive index when methane docks on to cryptophane-A supra-molecules that are mixed in to the polymeric film. It is the occurrence of methane in solution, which changes either the refractive index measured with high resolution Surface Plasmon Resonance (SPR; Chinowsky et al., 2003; Boulart et al, 2012b) or the transmitted power measured with differential fiber-optic refractometer (Boulart et al., 2012a; Aouba et al., 2012).- Using the developed sensors for the study of the CH4 cycle in relevant oceanic environment (the GODESS station in the Baltic Sea, Task 4 and 5; IOW, GET); GODESS registers a number of parameters with high temporal and vertical resolution by conducting up to 200 vertical profiles over 3 months deployment with a profiling platform hosting the sensor suite. - Quantifying methane fluxes to the atmosphere (Task 6); clearly, the current project, which aims at developing in-situ aqueous gas sensors, provides the technological tool to achieve the implementation of ocean observatories for CH4. The aim is to bring the fiber-optic methane sensor on the TRL (Technology Readiness Level) from their current Level 3 (Analytical and laboratory studies to validate analytical predictions) - to the Levels 5 and 6 (Component and/or basic sub-system technology validation in relevant sensing environments) and compare it to the SPR methane sensor, taken as the reference sensor (current TRL 5). This would lead to potential patent applications before further tests and commercialization. This will be achieved by the ensemble competences and contributions from the proposed consortium in this project.

14C content of specific organic compounds in subsoils

Organic matter (OM) composition and dynamic in subsoils is thought to be significantly different from those in surface soils. This has been suggested by increasing apparent 14C ages of bulk soil OM with depth suggesting that the amount of fresh, more easily degradable components is declining. Compositional changes have been inferred from declining ä13C values and C/N ratios indicative for stronger OM transformation. Beside these bulk OM data more specific results on OM composition and preservation mechanisms are very limited but modelling studies and results from incubation experiments suggest the presence and mineralization of younger, 'reactive carbon pool in subsoils. Less refractory OM components may be protected against degradation by interaction with soil mineral particles and within aggregates as suggested by the very limited number of more specific OM analysis e.g., identification of organic compound in soil fractions. The objective of this project is to characterize the composition, transformation, stabilization and bioavailability of OM in subsurface horizons on the molecular level: 1) major sources and compositional changes with depth will be identified by analysis of different lipid compound classes in surface and subsoil horizons, 2) the origin and stabilization of 'reactive OM will be revealed by lipid distributions and 14C values of soil fractions and of selected plant-specific lipids, and 3) organic substrates metabolized by microbial communities in subsoils are identified by distributional and 14C analysis of microbial membrane lipids. Besides detailed analyses of three soil profiles at the subsoil observatory site (Grinderwald), information on regional variability will be gained from analyses of soil profiles at sites with different parent material.

Wovon wir reden, wenn wir von Unsicherheit reden - Eine Bewertung der Bayes'schen Statistik als Mittel zur hydrogeologischen Unsicherheitsanalyse

Die Relevanz von Unsicherheitsanalysen in der Hydrogeology ist vergleichsweise groß aufgrund der Tatsache, dass Aquifereigenschaften oft sehr heterogen sind und meist nur wenige in-situ Daten zu deren Charakterisierung zu Verfügung stehen. Die Bayes'sche Statistik ist hervorragend geeignet, um solche Analysen durch zu führen. Verglichen mit klassicher, frequentistischer Statistik lassen sich Unsicherheiten deutlich einfacher modellieren, können Wahrscheinlichkeitsaussagen auch für Einzelfälle getroffen werden und Hintergrundwissen von ex-situ Messungen konsistent mittels der A-priori-Verteilung repräsentiert werden. In der Praxis werden allerdings sowohl Unsicherheitsanalyse wie auch Aquifercharakterisierung nur selten mit Bayes'schen Methoden durchgeführt. Der wahrscheinlich wichtigste Hinderungsgrund ist dabei die Schwierigkeit die A-priori-Verteilung zu bestimmen, welche die (Un)sicherheit bzgl. der Aquifereigenschaften ausdrückt bevor in-situ Daten berücksichtigt wurden. In diesem Projekt werde ich dieses Problem angehen, in dem ich (i) einen Arbeitsablauf zur Bestimmung der A-priori-Verteilung ausarbeite und (ii) den Einfluss solch einer Verteilung untersuche. Im ersten Teil werde ich Gebrauch machen von dem hierarchischem Bayes'schen Modell zur Bestimmung von A-priori-Verteilungen, welches in einer Zusammenarbeit zwischen der Arbeitsgruppe von Prof. Yoram Rubin und mir entwickelt wurde. Um dieses Modell mit einem umfangreichen und repräsentativen Datensatz zu versorgen, werde ich es mit einer etablierten Datenbank hydrogeologischer Messungen koppeln. Dadurch wird es möglich informative A-priori-Verteilungen zu bestimmen, welche das Hintergrundwissen von ex-situ Messungen repräsentieren. Im zweiten Teil werde ich den Einfluss dieser informativen A-priori-Verteilungen auf Fragen der Unsicherheitsreduktion und des resultierenden Datenwertes untersuchen. Dazu werde ich eine Reihe von klassischen Meß- und Interpretationsverfahren mit einem Bayes'schen Aquivalent vergleichen. Dabei wird vor allem die Frage des relativen Datenwertes im Mittelpunkt stehen. Relativ bezieht sich hierbei auf den Einfluss von in-situ Daten verglichen mit den ex-situ Daten, welche in der A-priori-Verteilung enthalten sind. Die Ergebnisse dieses Projektes werden demnach helfen einen konsistenten und reproduzierbaren Arbeitsablauf zur Ableitung hydrogeologischer A-priori-Verteilungen zu etablieren sowie deren Einfluss auf Fragen der Unsicherheitsreduktion und des relativen Datenwertes von in-situ Messungen zu bestimmen. Des Weiteren werden die Ergebnisse dazu dienen die Vorteile sowie mögliche Nachteile Bayes'scher Methoden für die hydrogeologische Unsicherheitsanalyse zu verstehen. Dadurch werden die Herausforderungen klar, die zu überwinden sind, um Bayes'sche Statistik zu einem allgemein genutztem Standard für hydrogeologische Unsicherheitsanalysen werden zu lassen.

Mesoskaliges Netzwerk zur Überwachung von Treibhausgas- und Schadstoffemissionen

Aktuelle wissenschaftliche Studien legen nahe, dass die aktuelle Erderwärmung durch Treibhausgasemissionen hervorgerufen wird, die vom Menschen verursacht sind. Um gegen diese Entwicklung geeignete Maßnahmen ergreifen zu können bzw. um zu überprüfen, ob solche Maßnahmen von Erfolg gekrönt sind, ist es notwendig, die Schadstoffkonzentrationen inklusive der zugehörigen Emissionsquellen genau zu kennen. Diese Informationen sind bisher jedoch sehr lückenhaft und beruhen auf sogenannten 'bottom-up' Berechnungen. Da diese Kalkulationen nicht auf direkten Messungen beruhen, weisen sie große Ungenauigkeiten auf und sind außerdem nicht in der Lage, bisher unbekannte Emissionsquellen zu identifizieren. In dem hier vorgestellten Projekt soll ein mesoskaliges Netzwerk für die Überwachung von Luftschadstoffen wie CO2, CH4, CO, NO2 und O3 aufgebaut werden, das auf dem neuartigen Konzept der differentiellen Säulenmessung beruht. Bei diesem Ansatz wird die Differenz zwischen den Luftsäulen luv- und leewärts einer Stadt gebildet. Diese Differenz ist proportional zu den emittierten Schadstoffen und somit eine Maßzahl für die Emissionen, welche in der Stadt generiert werden.Mithilfe dieser Methode wird es in Zukunft möglich sein, städtische Emissionen über lange Zeiträume hinweg zu überwachen. Damit können neue Informationen über die Generierung und Umverteilung von Luftschadstoffen gewonnen werden. Wir werden u.a. folgende zentrale Fragen beantworten: Wie verhält sich der tatsächliche Trend der CO2, CH4 und NO2 Emissionen in München über mehrere Jahre? Wo sind die Emissions-Hotspots? Wie akkurat sind die bisherigen 'bottom-up' Abschätzungen? Wie effektiv sind die Maßnahmen zur Emissionsreduzierung tatsächlich? Sind vor allem für Methan weitere Maßnahmen zur Reduzierung der Emissionen notwendig? Zu diesem Zweck werden wir ein vollautomatisiertes Messnetzwerk aufbauen und passende Methoden zur Modellierung entwickeln, welche u.a. auf STILT (Stochastic Time-Inverted Lagrangian Transport) und CFD (Computational Fluid Dynamics) basieren. Mithilfe der Modellierungsresultate werden wir eine Strategie entwerfen, wie städtische Netzwerke zur Überwachung von Luftschadstoffen aufgebaut werden müssen, um repräsentative Ergebnisse zu erhalten. Außerdem können mit den so gewonnenen städtischen Emissionszahlen z.B. dem Stadtreferat, den Stadtwerken München oder der Bayerischen Staatsregierung Möglichkeiten zur Beurteilung der Effektivität der angewandten Klimaschutzmaßnahmen an die Hand gegeben werden. Das hier vorgestellte Messnetzwerk dient somit als Prototyp, um die grundlegenden Fragen zum Aufbau eines solchen Sensornetzwerks zu klären, damit objektive Aussagen zu städtischen Emissionen möglich werden. Dieses Projekt ist weltweit einmalig und wird zukunftsweisende Ergebnisse liefern.

Water use characteristics of bamboo (South China)

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.

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