http://etd.aau.edu.et:80/dspace/handle/123456789/393 Search the Channel search http://etd.aau.edu.et:80/dspace/simple-search http://etd.aau.edu.et:80/dspace/handle/123456789/4714 Title: MAPPING OF SOIL SALINITY IN SEGO IRRIGATION FARM, SOUTHERN ETHIOPIA USING GEOSPATIAL TOOLS <br/> <br/>Authors: Zewdu, Shegena <br/> <br/>Abstract: Salinization is the major problem of the irrigated agriculture in arid and semi-arid areas, which adversely reduce the productivity of agricultural lands. Managing salinity so as to minimize its environmental impact is a prerequisite for the long-term sustainability of irrigated agriculture. The main objective of this study was to assess the level of salinity in Sego irrigated farm and to map temporal and spatial distribution of salt affected soils to aid further management. The study employed normal image classification and developing models from NDSI versus ECe and from different thematic layers to map soil salinity using geospatial tools. Classification for Landsat image of 1984, 1995 and 2010 showed that land under intensive cultivation has significantly decreased in the 26 years period where 13 ha is put under fallow per year. The analysis of NDSI shows also the strongly saline soils have increased by 6 ha/yr. Empirical model was developed from ECe vs NDSI of 2010 image using regression analysis and it has shown coefficient of relation of 66%. The model was extended for the whole area and it has revealed that 2.0 % of the study area is strongly saline where 54.7 % of the area is non-saline. Overlay model was also developed from water table, landform, land management type, soil texture and land cover and the result showed about 26.6 % of the study area is non-saline where 39.5 % and 2.8 % is moderately and strongly saline respectively. Validation of the models was made to test their predication capability and hence overlay model has revealed better correlation coefficient of 68.0 % to the measured ECe. The map of salt affected soils derived from the overlay salinity model was used to assess the distribution of salt affected soil with respect to water table and soil type. The result showed that most of the salt affected areas are on shallow water table where the strongly saline soil accounting to 2.8 % is on the shallow water table. The distribution of salt affected area with respect to soil type shows that Cambisols and Fluvisols are greatly affected by salinity where Salonchaks and Solonetz are almost found on salt affected areas. Generally the result indicates that geospatial tools are efficient and feasible techniques for detecting salt affected areas from satellite images and different thematic maps. <br/> <br/>Description: Thesis Submitted to the School of Graduate Studies in Partial Fulfillment of the Requirements for the Degree of Master of Science in Geo-information Science http://etd.aau.edu.et:80/dspace/handle/123456789/4713 Title: GIS AND REMOTE SENSING BASED FERTILIZER SUITABILITY MAPPING FOR WHEAT(Triticum aestivum) AT LUME MICRO WATERSHED, CENTRAL ETHIOPIA <br/> <br/>Authors: TADESSE, HUNDUMA <br/> <br/>Abstract: Fertilizer suitability mapping is the way of determining fertilizer demanded by specific crop type on the basis of soil sample testing results. It is a very important method for modern precision agriculture to increase fertilizer use efficiency and environmental friendliness. Hence, in order to make efficient fertilizer application for wheat at Lume Micro Watershed, the study tried to map the plant macro nutrients, physical land suitability map and diammonium phosphate (DAP) suitability map for wheat. Starting from soil sample collection, laboratory analysis, spatial interpretation and mapping, standard analysis methods and GIS and remote sensing tools were used. The soil factors (drainage, depth, texture, pH, organic carbon, and phosphorus), temperature, rainfall, slope, elevation and land use/cover were considered in land suitability evaluation for wheat. In addition multi criteria evaluation was also used to generate values of relative influence for each factor of the objective. The diammonium phosphate suitability map was made by determining phosphorus critical level for wheat in the reference to initial soil phosphorus level in the soil. Finally by applying Krignig interpolation diammonium phosphate suitability was mapped for wheat. The potassium level in the study site is about 221.53 to372.11ppm.Total nitrogen and organic carbon are used as indicators of nitrogen in soil which is very low in the study area. The available phosphorus level in the study area ranges from very low, low, moderate to high level which demand variable rates of fertilizer requirement application. Initial land suitability for wheat is 9.45% highly suitable, 85.8% moderately suitable, 3.21% marginally suitable and 1.54% permanently not suitable. The diammonium phosphate requirement map of the area reveals that about 51.38%, 20.25%, 18.40% and 8.43% need 50 to75 kg/ha, 75 to 100kg/ha, 25 to 50kg/ha and greater than 100kg/ha respectively. The results are further verified by using soil sample points and their available soil phosphorus compared to diammonium phosphate suitability map and initial wheat suitability map. The validation revealed that the result is in good conformity with the actual soil available phosphorus. <br/> <br/>Description: A Thesis Submitted to: The School of Graduate Studies of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Masters of Science in Geoinformation Science http://etd.aau.edu.et:80/dspace/handle/123456789/4712 Title: Remote sensing and GIS based Wildlife corridor suitability for Nile Lechwe Species in Gambela National Park, Ethiopia <br/> <br/>Authors: Eyassu, Lemma <br/> <br/>Abstract: Gambella National Park is known for its wealth of wetlands and associated wildlife species like Nile Lechwe And Kobs which are currently in International Union for conservation of Nature Red List: Endangered in 2008. The aim of this research is to assess the suitability of wildlife corridors in Gambela National park for utilization and conservation of Nile Lechwe species With the help of remote sensing softwares and geospatial tools, so as for conservation and utility purposes, It was considered land use, wetlands and settlements proximity, slope and soil factors as principal elements for Nile Lechwe wildlife corridor suitability analysis. Different weights heave been given to these factors based on the responses of focus group discussions and key informant interviews regarding the relative influences of each of these factors on wildlife habitat of the area. The weights were calculated using pair-wise comparison method. Then weighted factors maps were integrated using weighted overlay analysis to run the wildlife corridor suitability model. Finally wildlife corridor map for Nile Lechwe was produced. The result of the land suitability analysis of wildlife corridors for selected species showed five classes of suitability ; From the total land of the study area 201.63 km2 (42.92%) was Highly suitable, 188 km2 (40.01%) Moderately suitable, 32.52 km2 (6.92%) marginally suitable, 28.47 km2 (6.06%) not suitable and 19.21km2 (4.09%) was permanently unsuitable area to be a Wildlife corridor for Nile Lechwe species. Building this information into conservation plans and management for Gambella area protected areas will help to address for conservation and management Nile Lechwe wildlife’s and its habitat landscapes. <br/> <br/>Description: A Thesis Submitted to the School of Graduate Studies of Addis Ababa University, in Partial fulfillment of the Requirements for the Degree of Master of Science in Geoinformation Science http://etd.aau.edu.et:80/dspace/handle/123456789/4710 Title: ESTIMATION OF ACTUAL EVAPOTRANSPIRATION AND ITS IMPACTS ON RAINFED AGRICULTURAL PRODUCTIVITY USING GEOSPATIAL TOOLS IN THE MAIN ETHIOPIAN RIFT <br/> <br/>Authors: DEBELE, ABERRA <br/> <br/>Abstract: Remote sensing based estimation of spatiotemporal patterns of vegetation water use has played significant roles in evaluation and monitoring of rainfed agriculture. Agriculture is the most vulnerable and sensitive sector that is seriously affected by the impact of climate variability and change, which is usually manifested through rainfall variability and recurrent drought in the Main Ethiopian Rift. The objective of this study is to estimate actual evapotranspiration for crop performance evaluation and monitoring for the study periods of 2001-2010 cropping seasons (June-September). Using VegET model that integrates commonly used water balance algorithms with remotely sensed Land Surface Phenology (LSP) parameter to conduct operational vegetation water balance modeling of rainfed systems at the LSP’s spatial scale using readily available global data sets. The result confirmed that the lowest seasonal /driest seasons/ water use estimated in 2002, which is 192mm and followed by 2003, 2009 and 2001cropping seasons with 205,230, and 231 mm respectively. On the contrary, moisture deficit free seasons’ were found during 2006–2008 and 2010 years with water use values ranges from 270-297 mm in depth. In the study area ETa and moisture availability (rainfall) have good positive linear relationship with coefficient of correlation (r=0.89). The result revealed that the highest yield reduction occurred during 2002 cropping season which is about 47% and then followed by 27%, 24%, 18%, and 18% in 2003, 2001, 2009 and 2005 cropping seasons respectively. The relationship between the water balance yield reduction estimation model and WRSI have good negative linear correlation determination coefficient (r=0.92). Finally, the VegET modeling approach was demonstrated to have a promising application for drought monitoring/crop performance/ and early warning applications at various spatial and time scales for rain-fed systems. <br/> <br/>Description: A Thesis submitted to the School of Graduate Studies in Partial Fulfillment of the Requirements for the Degree of Masters of Science in Geoinformation Science