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Die bewasserte Landwirtschaft in Zentralasien steht vor grosen Herausforderungen. Zum einen mussen die gravierenden Probleme der Vergangenheit abgearbeitet werden, deren Auswirkungen im Aralsee-Dilemma kumulieren. Daruber hinaus gilt es,... more
Die bewasserte Landwirtschaft in Zentralasien steht vor grosen Herausforderungen. Zum einen mussen die gravierenden Probleme der Vergangenheit abgearbeitet werden, deren Auswirkungen im Aralsee-Dilemma kumulieren. Daruber hinaus gilt es, Reaktionen auf eine Verscharfung von Dargebot-Bedarf-Engpassen zu finden, die als Folge der Klimaanderung und der zunehmenden Konkurrenz um die Wasserressourcen im Einzugsgebiet des Aralsees zu befurchten ist. In Zusammenarbeit mit der UNESCO bearbeitet das Zentrum fur Entwicklungsforschung (ZEF) der Universitat Bonn das Projekt ‚Okonomisch und okologisch orientierte Umstrukturierung der Landund Wassernutzung in der Region Khorezm, Usbekistan’. Khorezm ist eine am Unterlauf des Amu Darya gelegene usbekische Provinz mit 265.000 ha bewasserter Flache. Das Projekt zielt darauf ab, technische, institutionelle und sozio-okonomische Masnahmen zu transdisziplinaren Konzepten zu bundeln, um die Nutzung der Landund Wasserressourcen effizienter zu machen. Bisher im Projekt erzielte Ergebnisse der Analysen des Wasserbewirtschaftungssystems in Khorezm und daraus abgeleitete Umgestaltungsmasnahmen werden in diesem Artikel zusammengefasst. Schlagworter: Bewasserung, Usbekistan, Wasserbewirtschaftung, Wasserdargebot, Wassernutzung
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Dariusz Kurzatkowski1,2, Christopher Martius2,*, Hubert Höfer3, Marcos Garcia4, Bernhard Förster5, Ludwig Beck3 and Paul Vlek1,2 1Institute for Agronomy in the Tropics, University of Göttingen, Göttingen, Germany; 2Zentrum für... more
Dariusz Kurzatkowski1,2, Christopher Martius2,*, Hubert Höfer3, Marcos Garcia4, Bernhard Förster5, Ludwig Beck3 and Paul Vlek1,2 1Institute for Agronomy in the Tropics, University of Göttingen, Göttingen, Germany; 2Zentrum für Entwicklungsforschung (ZEF), Walter-Flex-...
Research Interests: Environmental Science, Chemistry, Analytical Chemistry, Agronomy, Decomposition, and 15 moreAgroforestry, Nutrient Cycling, Soil Respiration, Microbial Respiration, Litter, Plant Litter, Microbial Biomass, Amazon rainforest, Litter Decomposition, Bactris Gasipaes, Leaf Litter, Soil Mesofauna, Organic Matter, Monoculture, and Agroforestry System
Abstract This article gives an overview of the structure of the interdisciplinary GLOWA Volta Project and its main scientific outputs. The article serves to provide the context for a set of articles written by project scientists for this... more
Abstract This article gives an overview of the structure of the interdisciplinary GLOWA Volta Project and its main scientific outputs. The article serves to provide the context for a set of articles written by project scientists for this special issue of the Journal of River Basin Management. After a brief introduction, a description is given of the Volta Basin in West Africa. The main issues related to changes in water supply and demand are presented. Climate change and variability, landuse change, and increasing competition for water ...
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... Arroyo, L., Baker, TR, Killeen, T., Lewis, SL, Malhi, Y., Mendoza, AM, Neill, D., Vargas, PN, Alexiades, M., Ceron, C., Di Fiore, A., Erwin, T., Jardim, A., Palacios, W., Saldias M. & Vinceti, B. (2002) Increasing... more
... Arroyo, L., Baker, TR, Killeen, T., Lewis, SL, Malhi, Y., Mendoza, AM, Neill, D., Vargas, PN, Alexiades, M., Ceron, C., Di Fiore, A., Erwin, T., Jardim, A., Palacios, W., Saldias M. & Vinceti, B. (2002) Increasing dominance of large lianas in Amazonian forests. Nature, 418, 770774. ...
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The agricultural production of tropical Latin America is astonishingly low. The land area in Latin America that is suitable for crop production from a topographical standpoint varies from 95% in the plains to 75% on the plateaus, 25% in... more
The agricultural production of tropical Latin America is astonishingly low. The land area in Latin America that is suitable for crop production from a topographical standpoint varies from 95% in the plains to 75% on the plateaus, 25% in the hills, and 5% in the mountains. However, less than 5% of the total land area in tropical Latin America, approximately 1600 million ha, was under cultivation by 1950, largely because of adverse soil, geographic, or climatic conditions. Regionally the percentage of land under cultivation varied from 17% in the Caribbean Islands, to 9% in Central America and Mexico, down to 3% and 2% in Colombia and Brazil, respectively. According to estimates at the time, only 40% of the potentially arable land was being cultivated.
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Research-based improvements in small-farmer land-use systems are difficult to bring about. Often such improvements developed under research station conditions fail to address the true system problems or farmer concerns. In the search for... more
Research-based improvements in small-farmer land-use systems are difficult to bring about. Often such improvements developed under research station conditions fail to address the true system problems or farmer concerns. In the search for ways to improve the traditional fallow system of the Eastern Amazon, field experiments were conducted in farmers’ fields, but under researcher management with farmers helping to identify
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... of irrigation water is an important determinant of crop growth and agricultural drainage quality. ... the soil includes uptake by plants, downward transport by percolation and drainage (leaching), erosion ... Flood irrigation may also... more
... of irrigation water is an important determinant of crop growth and agricultural drainage quality. ... the soil includes uptake by plants, downward transport by percolation and drainage (leaching), erosion ... Flood irrigation may also cause the breakdown of soil aggregates by air slaking ...
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The Volta Basin covers 400,000 km2 of the West African savanna. The river feeds Lake Volta, that provides over 95% of the electricity in Ghana and has the largest surface of any man-made lake in the world. The rural population (per capita... more
The Volta Basin covers 400,000 km2 of the West African savanna. The river feeds Lake Volta, that provides over 95% of the electricity in Ghana and has the largest surface of any man-made lake in the world. The rural population (per capita income US600/year) increasingly turns to small scale irrigation development to improve the returns on their agricultural activities and
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As a result of fast growing population rates, increasing resources and industrial development, water is becoming a very scarce and valuable resource. Due to the scarcity of water and its quality related problems, the abilities of some... more
As a result of fast growing population rates, increasing resources and industrial development, water is becoming a very scarce and valuable resource. Due to the scarcity of water and its quality related problems, the abilities of some countries to supply their population with water and to satisfy their future water demand for the economic and environmental need are already affected. In a country sustainable development is possible if the water resources of a country are managed and utilized properly. Proper utilization of water resources requires knowledge, basic understanding of the hydrologic system and the processes influencing them both spatially and temporally.
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The Volta Basin covers 400 000 km 2 of the West-African savanna. Agriculture is the dominant economic activity. Given the extremely unreliable rainfall, irrigation development is seen as an obvious strategy to increase agricultural... more
The Volta Basin covers 400 000 km 2 of the West-African savanna. Agriculture is the dominant economic activity. Given the extremely unreliable rainfall, irrigation development is seen as an obvious strategy to increase agricultural production. Irrigation development is mainly linked to the construction of small and medium sized reservoirs. The potential use of groundwater for irrigation is a very important issue. In this study, we present an evaluation of the conjunctive use of surface and groundwater in a representative small reservoir-irrigation system. The physical processes are modelled with WaSiM-ETH. The physical boundary conditions needed for the optimization model are then passed on to the optimization model written in GAMS, which then simulates the capture and utilization of runoff in small reservoirs. Water can be withdrawn for irrigation, or stored. Irrigation water can also be pumped from the underlying aquifer, and pumping costs are modelled as proportional to the distance to the water table.
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Research Interests: Agronomy, Irrigation, Biomathematics, Modeling, Evaluation, and 15 moreBiometrics, Decision support system, Environmental Sciences, Dynamic Simulation, Ndvi, Cultivar, Partition Coefficient, Leaf Area Index, Model Evaluation, Mathematical Model, Aboveground biomass, Crop Rotation, Optimality Condition, Normalized Difference Vegetation Index, and Model performance
Research Interests: Environmental Science, Computer Science, Remote Sensing, Time Series, Logistics, and 15 moreWest Africa, Satellite remote sensing, Cellular Automata, Trajectory, Automation, Forest, Burkina Faso, Large River Ecology, Population Density, Land cover change, Vegetation, River Basin, Woodland, Enrichment factor, and Binary Logistic Regression
... challenge of the GLOWA Volta Project is to integrate the analysis of the bio-physical and socio-economic factors that affect the hydrological cycle in ... possible, and calculates weightingfactors; ... Each demand node is a location... more
... challenge of the GLOWA Volta Project is to integrate the analysis of the bio-physical and socio-economic factors that affect the hydrological cycle in ... possible, and calculates weightingfactors; ... Each demand node is a location where water is diverted to different sites for beneficial ...
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... In: Understanding Options for Agricultural Production. Ed. Gordon Y. Tsuji, Gerrit Hoogenboom and Philip K. Thornton. Kluwer Academic Publishers in cooperation with ICASA. Singh, RP, SK Das, UM Bhaskara Rao, and M. Narayana Reddy.... more
... In: Understanding Options for Agricultural Production. Ed. Gordon Y. Tsuji, Gerrit Hoogenboom and Philip K. Thornton. Kluwer Academic Publishers in cooperation with ICASA. Singh, RP, SK Das, UM Bhaskara Rao, and M. Narayana Reddy. 1990. ...
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Like many irrigation schemes in Central Asia, the one in Khorezm faces a two-fold challenge: on the one side, the severe problems inherited from the past need to be remedied and on the other side, the rising supply–demand gap driven by... more
Like many irrigation schemes in Central Asia, the one in Khorezm faces a two-fold challenge: on the one side, the severe problems inherited from the past need to be remedied and on the other side, the rising supply–demand gap driven by sharpening competition for water and climate change must be dealt with. Located in the lower part of the Amu Darya basin, Khorezm irrigation and drainage scheme is particularly vulnerable to supply–demand gaps. Promising solutions towards adaptation comprise modified strategies of land and water use towards higher efficiency and flexibility in combination with measures to lessen the constraints of the system itself, which was initially designed for the management of a few, large and uniform production units and not for many diverse and small units. Solutions consist of flexible, modeling-based approaches, re-arranging institutional settings and establishing economic incentive systems. Flexible modeling allows an integrated use of surface and groundwat...
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When horizontal resolutions of Soil-Vegetation-Atmosphere-Transfer (SVAT) models are large against land surface heterogeneity, subgrid-scale effects are usually not properly accounted for. It is state-of-the art that regional climate... more
When horizontal resolutions of Soil-Vegetation-Atmosphere-Transfer (SVAT) models are large against land surface heterogeneity, subgrid-scale effects are usually not properly accounted for. It is state-of-the art that regional climate models or mesoscale meteorological models (e.g. Penn State/NCAR-MM5) are fully coupled to SVAT-models (e.g. the Oregon-State-University Land-Surface Model, OSU-LSM) to describe the feedbacks between soil, vegetation and the planetary boundary layer. Meteorological models usually are applied in horizontal resolutions in the order of 5x5 to 50x50 km^2. SVAT-model input data (like vegetation and soil type and hence roughness length, albedo, emissivity and even stomatal resistance or hydraulic conductivities), however, are often available in much higher resolution. We therefore investigate into possibilities to account for the subgrid-scale effects on the gridscale itself. Our focus is on the proper representation of latent and sensible heat fluxes on grid ...
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Research Interests: Environmental Science, Geology, Geochemistry, Geophysics, Water Availability, and 14 moreWater Reuse, Irrigation water use efficiency, Water use efficiency, Evapotranspiration, Ground Water, Profitability, Surface Water, Water Resource, Production Function, Economic Value, Production System, Water Yield, Dry Season, and irrigation efficiency
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Abstract African farmers have relied traditionally on fallowing for up to 15 years to restore soil fertility. Leaving land unproductive for such periods is a luxury many regions cannot afford, given the contemporary decline in per capita... more
Abstract African farmers have relied traditionally on fallowing for up to 15 years to restore soil fertility. Leaving land unproductive for such periods is a luxury many regions cannot afford, given the contemporary decline in per capita food production (1%/year). Thus, ...
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The role of ammonia volatilization as a nitrogen loss mechanism in lowland rice (Oryza sativa L.) has recently been extensively reevaluated using techniques that do not disturb the field environment. This paper summarizes methodologies... more
The role of ammonia volatilization as a nitrogen loss mechanism in lowland rice (Oryza sativa L.) has recently been extensively reevaluated using techniques that do not disturb the field environment. This paper summarizes methodologies used in this research and discusses findings from recently conducted micrometeorological studies on ammonia volatilization. Factors affecting ammonia loss and the contribution of this process to