Browsing by Author "Tamirat Bekele"

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    Assessing Crop Suitability, Soil Moisture Dynamics, and Residual Soil Moisture Effects in a Changing Climate for Sustainable Agriculture in Ethiopia
    (Addis Ababa University, 2024-05) Tamirat Bekele; Teferi Demissie; Gulilat Tefera; Kasshun Ture
    Challenges to enhancing agricultural productivity in sub-Saharan Africa, particularly in Ethiopia where rain-fed agriculture is vital, are versatile. Human activities that alter the environment, combined with climate variability, soil degradation, and limited adoption of climate-smart technologies, exacerbate these challenges. This dissertation adopts an interdisciplinary approach, integrating climate science, soil science, and agronomy, to address some of these critical issues. It aims to identify soil moisture dynamics and its drivers, key food crops suitability, and the role of residual soil moisture to legume-based cropping systems in Ethiopia. A particular focus is given to soil moisture, a fundamental climate variable influencing local climate variability, soil properties, and agricultural productivity. Despite its significance, studies on soil moisture characteristics in Ethiopia are relatively sparse. Changes in crop suitability extents at the intersection of climate change and soil acidity are not sufficiently addressed. Moreover, the potential of residual soil moisture for post-harvest cropping remains under-explored. Therefore, this research assesses the spatiotemporal characteristics of soil moisture across Ethiopia and investigates the local and remote drivers influencing it. The study also examines the contributions of soil moisture to post-rainy season cropping by focusing on selected legume-based crops such as chickpeas (Cicer arietinum), field peas (Pisum sativum), common beans (Phaseolus vulgaris), soybeans (Glycine max), and alfalfa (Medicago sativa). Additionally, it evaluates the current and future suitability of key food crops like teff (Eragrostis tef ), maize (Zea mays L.), barley (Hordeum vulgare L.), and common wheat (Triticum aestivum L.) under changing climate and soil conditions from 1970 to 2020 and projected climate changes by 2050. The research employs several statistical methodologies, including Empirical Orthogonal Functions (EOF), Complex Maximum Covariance Analysis (CMCA), Kmeans clustering algorithm, crop models, and the Penman-Monteith equation, to investigate the spatiotemporal dynamics of soil moisture, crop suitability, and crop water demands. The analysis reveals significant variability in soil moisture across Ethiopia, with a distinct gradient between the eastern and western regions. Interannual variability of the soil moisture is primarily driven by rainfall patterns, while evapotranspiration significantly influences soil moisture dynamics in the east. Global oceanic indices such as the Oceanic Niño Index (ONI, r = 0.72), Indian Ocean Dipole (IOD, r = 0.43), Pacific warm pool (PACWARMPOOL, r = 0.48), and Pacific Decadal Oscillations (PDO, r = -0.52) are closely associated with local soil moisture anomalies. The combined impacts of climate change and soil acidity on key food crops indicate that while climate change alone may not drastically affect crop suitability, its superimposition with soil acidity leads to adverse effects, reducing suitability for all crops (e.g., -26.7% for teff, -8.7% for maize, -30.9% for barley, and -34.3% for wheat). While the post-rainy season (OND) is not the same across the country, residual soil moisture analysis during the post-rainy season shows adequate moisture reserves in the western, central, and southwestern regions of Ethiopia. In these regions, crop water demand is adequately met by residual soil moisture during the initial and late growing stages of the crops; however, residual soil moisture is insufficient to meet crop water demands during the mid-season crops development stage. Conversely, the northern and southeastern tips of the country face unreliable residual moisture levels due to adverse climate conditions and prolonged dry periods (> 150 days), resulting in insufficient residual soil moisture to meet crop water demand in these regions. Findings from this dissertation provides valuable insights into the spatiotemporal dynamics of soil moisture and its critical role in post-rainy season cropping and crop suitability under the changing climate and soil conditions in Ethiopia. Furthermore, the findings contribute to the overarching goal of agricultural sustainability, providing insights for long-term climate resilient cropping systems while maintaining minimal disruption to the environment.
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    Assessing Crop Suitability, Soil Moisture Dynamics, and Residual Soil Moisture Effects in a Changing Climate for Sustainable Agriculture in Ethiopia
    (Addis Ababa University, 2024-05) Tamirat Bekele; Teferi Demissie (PhD); Gulilat Tefera (PhD); Kasshun Ture (PhD)
    Challenges to enhancing agricultural productivity in sub-Saharan Africa, particularly in Ethiopia where rain-fed agriculture is vital, are versatile. Human activities that alter the environment, combined with climate variability, soil degradation, and limited adoption of climate-smart technologies, exacerbate these challenges. This dissertation adopts an interdisciplinary approach, integrating climate science, soil science, and agronomy, to address some of these critical issues. It aims to identify soil moisture dynamics and its drivers, key food crops suitability, and the role of residual soil moisture to legume-based cropping systems in Ethiopia. A particular focus is given to soil moisture, a fundamental climate variable influencing local climate variability, soil properties, and agricultural productivity. Despite its significance, studies on soil moisture characteristics in Ethiopia are relatively sparse. Changes in crop suitability extents at the intersection of climate change and soil acidity are not sufficiently addressed. Moreover, the potential of residual soil moisture for post-harvest cropping remains under-explored. Therefore, this research assesses the spatiotemporal characteristics of soil moisture across Ethiopia and investigates the local and remote drivers influencing it. The study also examines the contributions of soil moisture to post-rainy season cropping by focusing on selected legume-based crops such as chickpeas (Cicer arietinum), field peas (Pisum sativum), common beans (Phaseolus vulgaris), soybeans (Glycine max), and alfalfa (Medicago sativa). Additionally, it evaluates the current and future suitability of key food crops like teff (Eragrostis tef ), maize (Zea mays L.), barley (Hordeum vulgare L.), and common wheat (Triticum aestivum L.) under changing climate and soil conditions from 1970 to 2020 and projected climate changes by 2050. The research employs several statistical methodologies, including Empirical Orthogonal Functions (EOF), Complex Maximum Covariance Analysis (CMCA), Kmeans clustering algorithm, crop models, and the Penman-Monteith equation, to investigate the spatiotemporal dynamics of soil moisture, crop suitability, and crop water demands. The analysis reveals significant variability in soil moisture across Ethiopia, with a distinct gradient between the eastern and western regions. Interannual variability of the soil moisture is primarily driven by rainfall patterns, while evapotranspiration significantly influences soil moisture dynamics in the east. Global oceanic indices such as the Oceanic Niño Index (ONI, r = 0.72), Indian Ocean Dipole (IOD, r = 0.43), Pacific warm pool (PACWARMPOOL, r = 0.48), and Pacific Decadal Oscillations (PDO, r = -0.52) are closely associated with local soil moisture anomalies. The combined impacts of climate change and soil acidity on key food crops indicate that while climate change alone may not drastically affect crop suitability, its superimposition with soil acidity leads to adverse effects, reducing suitability for all crops (e.g., -26.7% for teff, -8.7% for maize, -30.9% for barley, and -34.3% for wheat). While the post-rainy season (OND) is not the same across the country, residual soil moisture analysis during the post-rainy season shows adequate moisture reserves in the western, central, and southwestern regions of Ethiopia. In these regions, crop water demand is adequately met by residual soil moisture during the initial and late growing stages of the crops; however, residual soil moisture is insufficient to meet crop water demands during the mid-season crops development stage. Conversely, the northern and southeastern tips of the country face unreliable residual moisture levels due to adverse climate conditions and prolonged dry periods (> 150 days), resulting in insufficient residual soil moisture to meet crop water demand in these regions. Findings from this dissertation provides valuable insights into the spatiotemporal dynamics of soil moisture and its critical role in post-rainy season cropping and crop suitability under the changing climate and soil conditions in Ethiopia. Furthermore, the findings contribute to the overarching goal of agricultural sustainability, providing insights for long-term climate resilient cropping systems while maintaining minimal disruption to the environment.
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    A Study on the Status of Public Primary School Physical Plants in Addis Ababa
    (Addis Ababa University, 1999-05) Tamirat Bekele; Ayalew Shibeshi
    Be purpose of the study was to make a survey on the current status of public primary .cbools in the city of Addis Ababa. Ute needed data was obtained by means of questionnaires distributed to 30 school \U1cipa!s, 28 members of school administrative committees, and 210 teachers working in Upublic primary schools randomly selected from five study "Zones" of the city. it data was analyzed using both descriptive and inferential statistics. Accordingly the !leiI.fch revea led the following results. fit of public school physical plants were found to be inadequate to implement various ~cl programmes because they were not primarily designed for educational purposes, ~~yen those which were designed for educational purposes were built without overall gS,S/S\Ilents and appropriate design. lnaddition, more than half of the public schools did t; ~~e legally acceptable school map and plan. 0 0 Ir1 -t::bcs\udy, school principals and teachers showed much .similar perception with regard 'VlIating the adequacy and comfortability of school plants than members of school to e jJT;.trative committees. a~ 1 -c thool physical plants were not located according to their functional relationships pub "J o \tes comfortable for teaching-learning processes. Hence, the school compounds, and 0 cl&stoOms, staff-rooms and offices were not convenient for teaching-Ieaming tb e seland administrative activities. Almost all public school physical plants were by (oceS P 1 ~the standard set by the MOE. fi:l(be 0 . scl\)ols lack the necessary repair and maintenance, for the reason that the public onsibiliy was left to school administrative committeeS-Almost all of the respondents resP. d Jltither the ed ucatI.O na I 0 ffiI ces nor t he surroun dm' g commuru.t y m. vo Iv ed m. . dlcate Ill . d llIlintenance of public schools. repaIr an Most of these schools did not have educational facilities like libraries, laboratories, space and facilities for subjects that require practical activities. The mam financial sources for public schools were found to be school fees. The participation of school committees, parents, the surrounding community in the affairs of public school physical plants was insignificant. There are no clear-cut policy statements and general guidelines about the organization and administration of public schools. If these problems are to be met forth rightly and directly, then careful planning and study are necessary. If successful solutions with successful answers are to be arrived at, cooperative action is desired between professional educational staff, the board of education, other community agencies and all citizens of the community.