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sur le développement des zones arides et semi-arides

Titre : Spatial analysis of land suitability to support alternative land uses at excelsior resettlement project, Oshikoto region, Namibia

Auteur : Mwazi, F.N. (Fidelis Nyambe)

Etablissement de soutenance : University of Twente International Institute for Geo-Information Science and Earth Observation (ITC)

Grade : Master of Science in Geo-Information Science and Earth Observation 2006

Résumé
Since the year 1990 the government of the Republic of Namibia has embarked on a land reform programme which is a process of acquiring land, through the current system of willing seller – willing buyer, to the actual resettlement of individuals on the land purchased for such purpose. The main aim of the resettlement programme is to enhance the welfare of the people through improvement of productivity, and to develop destination areas where they are supposed to earn a decent living. However, the success of resettlement is constrained by a number of limitations during implementation such as shortage of land use planners, land evaluators and land managers. The main aim of this study was land evaluation and land use and cover change analysis in space over time. The Excelsior Resettlement project in Oshikoto region is the object of study in this thesis. Interviews with settlers and experts took place during field work. Soil surveys were carried out to determine the land characteristics of each Land Evaluation Unit (LEU). Supporting secondary data were also collected. Actual land use types at the project are Livestock production (Cattle & Goats) Rain-fed maize and pearl millet. Two approaches were used : a qualitative method based on expert knowledge and a quantitative model based approach, referred to as K2 & K4 level in Bouma (2000). Expert knowledge, secondary data and existing literature (K2 approach) were captured into the expert system Automated Land Evaluation System (ALES) to determine the physical suitability of each LEU for both current and potential land uses. Soil and climatic data were inserted into CropWat (K4 approach) to simulate crop water requirements, effective rainfall, and evapotranspiration and to assess the yield reductions in the given conditions. Each LEU (point/Post) was evaluated for its suitability of LUTs that included cowpea, maize, pearl millet, sorghum and rangeland (grazing). Most of these LUTs had moderate or marginal suitability for the different LEUs. The method of land use and cover change detection by comparing classification was applied to identify land-use and land cover changes using difference satellite images (1990, 2000 & 2005). Normalized Difference Vegetation Index (NDVI) was also used for land use and cover change analysis of the project. Results of the change detection analysis reveals land use and cover changes in space over time, due to homestead construction, extra dryland needed for cropping and bush thickening as a result of woody plants invading the open areas. The overall changes are accounted for 43% while unchanged is 57%

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