Abebe Fanta | Haramaya university (original) (raw)

Papers by Abebe Fanta

RePEc: Research Papers in Economics, 2014

Floodwater management and sedimentation are the key issues which should be considered during the ... more Floodwater management and sedimentation are the key issues which should be considered during the development of new, or improvement of existing, spate irrigation schemes. The traditional intakes are superior in their site location, flexibility, and sediment-control capability. However, they have been frequently damaged by floods resulting in loss of continuous irrigation supply. The modern structures, albeit strong enough to withstand the impact force of the largest floods, suffer from large sedimentation problems. Farmers of Aba’ala Plain have been struggling with sedimentation and floodwater-management problems associated with their modern and traditional intakes. The objective of this research is, thus, to study the existing flood and sediment management practices and identify alternative options for optimum management of floods and sediments in the Aba’ala Plain, Afar. Aba’ala is the largest plain in the arid lowlands of Ethiopia where a combination of traditional, improved and modern spate irrigation systems are practiced. Extensive fieldwork was undertaken leading to measurement and collection of primary data including discharge, sediments and river cross sections. Interviews and focal group discussions were also employed and these generated deeper insights into O&M activities. In addition, Alluvial Friction Predictor and Sand Transport Predictor of SHARC model were employed to generate sediment concentration of the floodwater. Delft3D, a hydrodynamic model, has been used to simulate flow patterns and sedimentation under the existing condition and for different improvement options. For the existing condition (scenario-I), results of the model simulation showed high sediment deposition and low floodwater abstraction rate. Consequently, only 41 and 23% of the command areas under the modern and traditional intakes can be fully irrigated during the bad flood season. The high intake diversion rate and the reduced sedimentation around the intake were achieved with the improvement options under scenario-II (four consecutive bed stabilizers, a 30 m guiding wall upstream of the modern intake and reinforcement of the traditional intake). However, this scenario has a potential to cause conflict between upstream and downstream users as the result showed a decline of water level (15 cm) at the downstream intake. Therefore, scenario-III is recommended for a maximum floodwater diversion and minimum sediment deposition with a fair share of water between upstream and downstream intakes. This scenario would consist of open gabion reinforced multiple intakes with a 78 m long guide wall upstream of the modern intake, a 30 m long guide wall upstream of the traditional intake and a series of four bed stabilizers upstream of the diversion point.

Momona Ethiopian Journal of Science, 2019

Human's unwise and ineffective exploitation behavior has caused losses of the vital natural resou... more Human's unwise and ineffective exploitation behavior has caused losses of the vital natural resources, soil and water, which will definitely leave the future of the next generation in jeopardy. As a result of human intervention and natural causes most lakes in Ethiopia are shrinking in size while others are showing increase in volume. The intensive exploitation, beyond its regeneration rate, of the Lake Haramaya for water supply and agricultural purposes by the community within and outside its catchment boundary has led to its extinction. Although, some studies have been conducted on land use/land cover dynamics, the focus given to quantification of temporal variability lake surface area and the impact of weather variability on the lake water was inadequate. Hence, this study was conducted with the prime objective of mapping/quantifying the temporal lake surface area fluctuation using time series remote sensing images and investigating the impact of weather/climate variability on the lake. After acquiring Landsat images of the years 1985, 1995, 2003, 2010 and 2016 over the dry Haramaya Lake basin (path/row 166/54), the Modified Normalized Difference Water Index (MNDWI) and the Normalized Difference Vegetation Index (NDVI) were used for enhancing and extracting the open water surface of the lake. All of the enhanced images display a trend of decreasing lake surface water area with an average shrinkage of 23.6% between the year 1985 and up to its disappearance. After 2000 the lake surface area shrinkage was at its maximum which has a direct relation with the occurrence of dry weather as a result of relatively higher temperature and low rainfall between the years 2000 to 2003.

Land

An on-farm field experiment on a locally adapted conservation tillage method was undertaken to ev... more An on-farm field experiment on a locally adapted conservation tillage method was undertaken to evaluate its effect on soil erosion, surface runoff, and agronomic parameters. It was conducted on five farmer fields with 3–14% slopes in the Rift Valley and the Eastern escarpment of Ethiopia’s central highlands region for two cropping seasons. The treatments were conventional tillage (CT), repeated ploughing performed with a traditional ox-drawn plough named ‘Maresha’, and minimized contour ploughing (MT) at most twice with a locally adapted sweep-like attachment assembled to Maresha. Surface runoff and soil loss in the MT system were 30 to 60% and 49 to 76% lower than those in the CT system on 3 to 14% slopes, respectively. Despite the wide variation in surface runoff, limited differences in soil water content for the depth from 0 to 20 cm were observed between the treatments. Significant differences (p < 0.05) in grain yields (kg ha−1) of 246 and 323 in the 1st and 2nd growing seas...

Ethiopian Journal of Agricultural Sciences, May 5, 2021

Traditional methods of grading potato tubers require high labor-hour, cause fatigue to workers an... more Traditional methods of grading potato tubers require high labor-hour, cause fatigue to workers and has low output. Hence, engine driven machine capable of grading potato tubers into different size classes was evaluated. The grader prototype consisted of feeding table, grading cylinder and catchment tray. Grading capacity, grading system efficiency, mechanical damage and fuel consumption were used to determine the performance of the machine. Split-split-plot experimental design where grading cylinder speeds (10, 15, 20 rpm) were the main plots, angle of inclinations (5, 10, and 15°) as sub-plots and feeding rates (20, 30, 40 Kg.min-1)as sub-sub-plots with three replications were used. The results indicated that grading capacity and fuel consumption increased with increasing cylinder speed and feed rate while percentage mechanical damage and grading system efficiency decreased with increasing angle of inclination. The maximum grading system efficiency of 97.57% and 97.67 % was observed, when the machine was operated at speed of 15rpm, angle of inclination of 5° and feed rate of 20 and 30 kg.min-1 , respectively. From the performance indices, it can be concluded that the performance of the machine is very much acceptable with high prospect for extending the technology for small and medium scale farmers and potato whole sellers along the value chain..

Traditional methods of grading potato tubers require high man-hour, cause fatigue to workers and ... more Traditional methods of grading potato tubers require high man-hour, cause fatigue to workers and has low output. Hence, engine driven machine capable of grading potato tubers into different size classes was designed, manufactured, tested and evaluated. The prototype grader consisted of frame, feeding table, grading cylinder, catchment tray, shaft, pulleys and belt and transportation wheels. Tubers of Gudene potato variety widely grown in Ethiopia were used in the performance evaluation. Physical attributes such as major, intermediate and minor diameters, density and repose angle were studied. The experimental design used was laid in split-split-plots where grading cylinder speeds (10, 15, 20 rpm) were main plots, angle of inclinations (5, 10, and 15°) were sub-plots and feeding rates (20, 30, 40 Kg.min-1) were sub-sub-plots with three replications. Performance evaluation of the prototype machine was carried out in terms of grading capacity, grading system efficiency, mechanical damage and fuel consumption. The results indicated that grading capacity and fuel consumption of the grader increased with increasing cylinder speed and feed rate while percentage mechanical damage and grading system efficiency decreased with increasing angle of inclination. The maximum grading system efficiency of 97.57 and 97.67% was observed, when the machine was operated at

American Journal of Applied Scientific Research, 2021

Warqe processing is carried out dominantly by women using traditional tools such as a bamboo scra... more Warqe processing is carried out dominantly by women using traditional tools such as a bamboo scraper, serrated wooden tool and metal knife where losses in quality and quantity are exceptionally high. Above all, the traditional way of warqe processing causes physically drudgery among the rural women. In an effort to alleviate the problem, an engine is driven warqe decorticating machine was designed, constructed, tested and evaluated at field conditions. The performance evaluation of the machine was made in terms of decorticating capacity, decorticating efficiency, percentage pulp loss, and fuel consumption. The performance evaluation was carried out at three levels of drum speeds (850, 950 and 1050 rpm), concave clearances (1, 3 and 6 mm) and feeding rates (0.037, 0.056 and 0.074 kg/s, these are based on the feeding rates of 1.00, 1.50 and 2.00 kg/27s) to determine the optimum combination of the same. The experimental design laid was factorial, in the splitsplit plot. The maximum decorticating capacity of 255.38 kg/hr was obtained at a drum speed of 850 rpm, concave clearance of 1 mm and feeding rate of 0.074 kg/s. The decorticating efficiency and percentage un-decorticated pulp highly depended on concave clearance rather than other factors. Maximum decorticating efficiency 98.97% and minimum pulp loss of 1.03% were achieved at drum beater speed of 850 rpm and concave clearance of 1mm. The production cost of the decorticator was found to be 28,322.00 Birr. The total operating cost of the decorticator estimated to be, 48,925.38 Birr and the payback period and benefit-cost ratio of the prototype decorticating machine were estimated to be 0.90 years and 1.64, respectively.

Based on previous results indicating excessive milling loss inherent in rice milling process in E... more Based on previous results indicating excessive milling loss inherent in rice milling process in Ethiopia, a study was conducted to evaluate the effects of parboiling treatment on three released (Gumara, Kokit, and Tigabe) and one local (X-Jigna) rice varieties. Parboiled and un-parboiled rice samples were milled using small and portable Rice Whitener (SRW). The result has indicated that the response for Parboiling is variety specific. But, in general, parboiling resulted in improved milling quality in most of the studied varieties. An overall increase in Milling yield (from 62.70 to 65.83%), milling recovery (from 79.50 to 83.97%) and whole grain yield (from 27.83 to 37.68%), was observed while milling loss has reduced (from 16.50 to 12.50%) by this treatment. Likewise, parboiling reduced machine throughput and output. Milling qualities of Gumara and Tigabe and, to some extent, Kokit varieties had been improver and that of X-Jigna declined when milled parboiled. Tigabe and Kokit had...

Springer Geography, 2015

Effect of filter press mud (FPM) application on nutrient availability in Aquert and Fluvent soils... more Effect of filter press mud (FPM) application on nutrient availability in Aquert and Fluvent soils at Wonji-Shoa Sugarcane Plantation, located at central part of the East African Rift Valley, was studied during the 2003/04 growing season. The rate of FPM application was 0, 60 and 120 ton/h. Field monitoring was made for ninety days. As per the management practice of the Sugar Estate, the Aquert soil was green manured with Crotalarea junceae prior to the treatment application. Soil samples were collected and analyzed every fortnight for organic carbon (OC) and available N. Available P, exchangeable bases, Fe, and Mn content of the soil were monitored at the beginning and end of the experiment. Incorporation of FPM significantly increased the OC content in both soils. Nonetheless, the accumulation of OC was more in Aquert than Fluvent soils, due to the initial higher OC obtained from Crotalatea j., higher clay content and moist condition of the Aquert soil. The application of FPM promoted the available N though the availability of N ion, however, in both soils, the content declined during the first 45 days after application. Gradually, significant increase in the available N was observed (starting from 45th day of application up to the 90th day). This indicates that FPM having C/N ratio of 27 resulted in priming effect. The trend analysis made indicated that proportional increase in available P can be obtained with increasing rate of FPM application, though available K was found to be lower in FPM treated soils. The application of FPM buffered (reduced) the soil pH to 7.6. The highest rate of FPM application (120 ton/ha) slightly improved the soil electrical conductivity (EC). Furthermore, the study indicated that the application of FPM had the ability to reduce the soils exchangeable Na content. Thus, FPM has the potential to amend sodicity and abnormal pH of soils. However, it was noted that the application of FPM had reduced Fe/Mn ratio indicating its possible ability to slow down or reduce Fe uptake by plants. Therefore, prior checking for available K and Fe has to be made to ensure unnecessary consequences on sugarcane plants.

Water Resources Management, 2014

Floodwater management and sedimentation are the key issues which should be considered during the ... more Floodwater management and sedimentation are the key issues which should be considered during the development of new, or improvement of existing, spate irrigation schemes. The traditional intakes are superior in their site location, flexibility, and sediment-control capability. However, they have been frequently damaged by floods resulting in loss of continuous irrigation supply. The modern structures, albeit strong enough to withstand the impact force of the largest floods, suffer from large sedimentation problems. Farmers of Aba'ala Plain have been struggling with sedimentation and floodwater-management problems associated with their modern and traditional intakes. The objective of this research is, thus, to study the existing flood and sediment management practices and identify alternative options for optimum management of floods and sediments in the Aba'ala Plain, Afar. Aba'ala is the largest plain in the arid lowlands of Ethiopia where a combination of traditional, improved and modern spate irrigation systems are practiced. Extensive fieldwork was undertaken leading to measurement and collection of primary data including discharge, sediments and river cross sections. Interviews and focal group discussions were also employed and these generated deeper insights into O&M activities. In addition, Alluvial Friction Predictor and Sand Transport Predictor of SHARC model were employed to generate sediment concentration of the floodwater. Delft3D, a hydrodynamic model, has been used to simulate flow patterns and sedimentation under the existing condition and for different improvement options. For the existing condition (scenario-I), results of the model simulation showed high sediment deposition and low floodwater abstraction rate. Consequently, only 41 and 23% of the command areas under the modern and traditional intakes can be fully irrigated during the bad flood season. The high intake diversion rate and the reduced sedimentation around the intake were achieved with the improvement options under scenario-II (four consecutive bed stabilizers, a 30 m guiding wall upstream of the modern intake and reinforcement of the traditional intake). However, this scenario has a potential to cause conflict between upstream and downstream users as the result showed a decline of water level (15 cm) at the downstream intake. Therefore, scenario-III is recommended for a maximum floodwater diversion and minimum sediment deposition with a fair share of water between upstream and downstream intakes. This scenario would consist of open gabion reinforced multiple intakes with a 78 m long guide wall upstream of the modern intake, a 30 m long guide wall upstream of the traditional intake and a series of four bed stabilizers upstream of the diversion point.

Nile River Basin, 2014

ABSTRACT

Springer Geography, 2015

Soil compaction on sugar cane fields has been found to reduce yield and productivity. Influence o... more Soil compaction on sugar cane fields has been found to reduce yield and productivity. Influence of filter press mud (FPM), a residue obtained by filtration of the mud in cane juice clarification process, on compaction and consistency of Fluvent and Aquert soils was investigated on experimental plots. For compaction study, standard proctor test was employed and consistency parameters [liquid limit (LL) by drop cone method and plastic limit (PL)] were determined. Infield penetration resistances and basic infiltration were measured. The maximum dry bulk densities (MDBD) of the soils after standard proctor compaction were 1.42 and 1.30 g cm−3 at 28 and 29 % critical moisture content (CMC), respectively. For Fluvent, the CMC was at PL and on Aquerts at 66 % of the PL. For both soils, total porosity, degree of saturation and air-filled porosity were significantly improved by FPM application only at the CMC. Moreover, FPM increased cone index (CI) of the soil. On all experimental fields, the CI was below the critical value, but CI increment was observed around 20–25 cm depths after tillage. Basic infiltrations of the soils were 6.5 for Fluvent and 4.4 mm/h for Aquert, but effect of FPM was statistically non-significant.

Soil water infiltration is one of the most important processes affecting the volume, transport ro... more Soil water infiltration is one of the most important processes affecting the volume, transport route and water quality of agricultural drainage. Tillage method and depth have also effects on the ability of soil to store water and the furrow irrigation hydraulics of irrigated fields. A study was conducted to evaluate the effect of tillage method and depth on furrow irrigation hydraulics and soil water storage during the dry season at Dire Dawa, Eastern Ethiopia. Treatments in the study included were chisel, moldboard and disk ploughing to 150 mm and 250 mm depths; and “Maresha” (local plough). Data obtained through field measurement and/or observations and laboratory analysis included soil data, irrigation water, advance and recession times, inflow–outflow volumes, available soil moisture, and infiltration rate at each irrigation event. Extending tillage depth from 150 mm to 250 mm significantly increased irrigation infiltration (mm) from 34 to 38%, increased irrigation water advance time from 55 to 75%, increased application efficiency from 33 to 55%, and increased saturated hydraulic conductivity from 23 to 48%; and significantly decreased tail water ratio and distribution uniformity (p < 0.05) in the first two irrigations, but had little effect during the successive irrigations.

Abstract Tillage practices and depth of plow play an important role in altering the porosity and ... more Abstract Tillage practices and depth of plow play an important role in altering the porosity and infiltration capacity of soils and hence surface runoff and soil water availability. A study was conducted to evaluate the effect of tillage method and depth on grain yield and irrigation water use efficiency (IWUE) during the dry season at Dire Dawa, eastern Ethiopia. Treatments for this study included were chisel plow at 150 and 250 mm depth (CH 150 and CH 250 ), and disk plowing to 150 mm and 250 mm depths (DP 150 and DP 250 ); moldboard plow (MB 150 and MB 250 ) and “Maresha” (local plowing) (LP). Grain yield was determined by taking samples from three sections of the central furrow. Grain yields were adjusted to 10% moisture content. It was found that tillage method did not significantly affect the average grain and biomass yield and IWUE of grain and biomass. The grain yield for tillage method treatments averaged from 5325 kg/ha for local plow to 5839 kg/ha for disk plow. The effect of depth of plow on grain yield (kg/ha) ranges from 392 to 7108 for MB 150 and DP 250 , respectively. The IWUE (grain, kg/ha cm) for tillage depth treatments averaged from 16.73 for DP 150 to 30.90 for DP 250 , and their respective IWUE (biomass, kg/ha cm) averaged from 95.4 (MB 150 ) to 124.6 (CH 250 ).

RePEc: Research Papers in Economics, 2014

Floodwater management and sedimentation are the key issues which should be considered during the ... more Floodwater management and sedimentation are the key issues which should be considered during the development of new, or improvement of existing, spate irrigation schemes. The traditional intakes are superior in their site location, flexibility, and sediment-control capability. However, they have been frequently damaged by floods resulting in loss of continuous irrigation supply. The modern structures, albeit strong enough to withstand the impact force of the largest floods, suffer from large sedimentation problems. Farmers of Aba’ala Plain have been struggling with sedimentation and floodwater-management problems associated with their modern and traditional intakes. The objective of this research is, thus, to study the existing flood and sediment management practices and identify alternative options for optimum management of floods and sediments in the Aba’ala Plain, Afar. Aba’ala is the largest plain in the arid lowlands of Ethiopia where a combination of traditional, improved and modern spate irrigation systems are practiced. Extensive fieldwork was undertaken leading to measurement and collection of primary data including discharge, sediments and river cross sections. Interviews and focal group discussions were also employed and these generated deeper insights into O&M activities. In addition, Alluvial Friction Predictor and Sand Transport Predictor of SHARC model were employed to generate sediment concentration of the floodwater. Delft3D, a hydrodynamic model, has been used to simulate flow patterns and sedimentation under the existing condition and for different improvement options. For the existing condition (scenario-I), results of the model simulation showed high sediment deposition and low floodwater abstraction rate. Consequently, only 41 and 23% of the command areas under the modern and traditional intakes can be fully irrigated during the bad flood season. The high intake diversion rate and the reduced sedimentation around the intake were achieved with the improvement options under scenario-II (four consecutive bed stabilizers, a 30 m guiding wall upstream of the modern intake and reinforcement of the traditional intake). However, this scenario has a potential to cause conflict between upstream and downstream users as the result showed a decline of water level (15 cm) at the downstream intake. Therefore, scenario-III is recommended for a maximum floodwater diversion and minimum sediment deposition with a fair share of water between upstream and downstream intakes. This scenario would consist of open gabion reinforced multiple intakes with a 78 m long guide wall upstream of the modern intake, a 30 m long guide wall upstream of the traditional intake and a series of four bed stabilizers upstream of the diversion point.

Momona Ethiopian Journal of Science, 2019

Human's unwise and ineffective exploitation behavior has caused losses of the vital natural resou... more Human's unwise and ineffective exploitation behavior has caused losses of the vital natural resources, soil and water, which will definitely leave the future of the next generation in jeopardy. As a result of human intervention and natural causes most lakes in Ethiopia are shrinking in size while others are showing increase in volume. The intensive exploitation, beyond its regeneration rate, of the Lake Haramaya for water supply and agricultural purposes by the community within and outside its catchment boundary has led to its extinction. Although, some studies have been conducted on land use/land cover dynamics, the focus given to quantification of temporal variability lake surface area and the impact of weather variability on the lake water was inadequate. Hence, this study was conducted with the prime objective of mapping/quantifying the temporal lake surface area fluctuation using time series remote sensing images and investigating the impact of weather/climate variability on the lake. After acquiring Landsat images of the years 1985, 1995, 2003, 2010 and 2016 over the dry Haramaya Lake basin (path/row 166/54), the Modified Normalized Difference Water Index (MNDWI) and the Normalized Difference Vegetation Index (NDVI) were used for enhancing and extracting the open water surface of the lake. All of the enhanced images display a trend of decreasing lake surface water area with an average shrinkage of 23.6% between the year 1985 and up to its disappearance. After 2000 the lake surface area shrinkage was at its maximum which has a direct relation with the occurrence of dry weather as a result of relatively higher temperature and low rainfall between the years 2000 to 2003.

Land

An on-farm field experiment on a locally adapted conservation tillage method was undertaken to ev... more An on-farm field experiment on a locally adapted conservation tillage method was undertaken to evaluate its effect on soil erosion, surface runoff, and agronomic parameters. It was conducted on five farmer fields with 3–14% slopes in the Rift Valley and the Eastern escarpment of Ethiopia’s central highlands region for two cropping seasons. The treatments were conventional tillage (CT), repeated ploughing performed with a traditional ox-drawn plough named ‘Maresha’, and minimized contour ploughing (MT) at most twice with a locally adapted sweep-like attachment assembled to Maresha. Surface runoff and soil loss in the MT system were 30 to 60% and 49 to 76% lower than those in the CT system on 3 to 14% slopes, respectively. Despite the wide variation in surface runoff, limited differences in soil water content for the depth from 0 to 20 cm were observed between the treatments. Significant differences (p < 0.05) in grain yields (kg ha−1) of 246 and 323 in the 1st and 2nd growing seas...

Ethiopian Journal of Agricultural Sciences, May 5, 2021

Traditional methods of grading potato tubers require high labor-hour, cause fatigue to workers an... more Traditional methods of grading potato tubers require high labor-hour, cause fatigue to workers and has low output. Hence, engine driven machine capable of grading potato tubers into different size classes was evaluated. The grader prototype consisted of feeding table, grading cylinder and catchment tray. Grading capacity, grading system efficiency, mechanical damage and fuel consumption were used to determine the performance of the machine. Split-split-plot experimental design where grading cylinder speeds (10, 15, 20 rpm) were the main plots, angle of inclinations (5, 10, and 15°) as sub-plots and feeding rates (20, 30, 40 Kg.min-1)as sub-sub-plots with three replications were used. The results indicated that grading capacity and fuel consumption increased with increasing cylinder speed and feed rate while percentage mechanical damage and grading system efficiency decreased with increasing angle of inclination. The maximum grading system efficiency of 97.57% and 97.67 % was observed, when the machine was operated at speed of 15rpm, angle of inclination of 5° and feed rate of 20 and 30 kg.min-1 , respectively. From the performance indices, it can be concluded that the performance of the machine is very much acceptable with high prospect for extending the technology for small and medium scale farmers and potato whole sellers along the value chain..

Traditional methods of grading potato tubers require high man-hour, cause fatigue to workers and ... more Traditional methods of grading potato tubers require high man-hour, cause fatigue to workers and has low output. Hence, engine driven machine capable of grading potato tubers into different size classes was designed, manufactured, tested and evaluated. The prototype grader consisted of frame, feeding table, grading cylinder, catchment tray, shaft, pulleys and belt and transportation wheels. Tubers of Gudene potato variety widely grown in Ethiopia were used in the performance evaluation. Physical attributes such as major, intermediate and minor diameters, density and repose angle were studied. The experimental design used was laid in split-split-plots where grading cylinder speeds (10, 15, 20 rpm) were main plots, angle of inclinations (5, 10, and 15°) were sub-plots and feeding rates (20, 30, 40 Kg.min-1) were sub-sub-plots with three replications. Performance evaluation of the prototype machine was carried out in terms of grading capacity, grading system efficiency, mechanical damage and fuel consumption. The results indicated that grading capacity and fuel consumption of the grader increased with increasing cylinder speed and feed rate while percentage mechanical damage and grading system efficiency decreased with increasing angle of inclination. The maximum grading system efficiency of 97.57 and 97.67% was observed, when the machine was operated at

American Journal of Applied Scientific Research, 2021

Warqe processing is carried out dominantly by women using traditional tools such as a bamboo scra... more Warqe processing is carried out dominantly by women using traditional tools such as a bamboo scraper, serrated wooden tool and metal knife where losses in quality and quantity are exceptionally high. Above all, the traditional way of warqe processing causes physically drudgery among the rural women. In an effort to alleviate the problem, an engine is driven warqe decorticating machine was designed, constructed, tested and evaluated at field conditions. The performance evaluation of the machine was made in terms of decorticating capacity, decorticating efficiency, percentage pulp loss, and fuel consumption. The performance evaluation was carried out at three levels of drum speeds (850, 950 and 1050 rpm), concave clearances (1, 3 and 6 mm) and feeding rates (0.037, 0.056 and 0.074 kg/s, these are based on the feeding rates of 1.00, 1.50 and 2.00 kg/27s) to determine the optimum combination of the same. The experimental design laid was factorial, in the splitsplit plot. The maximum decorticating capacity of 255.38 kg/hr was obtained at a drum speed of 850 rpm, concave clearance of 1 mm and feeding rate of 0.074 kg/s. The decorticating efficiency and percentage un-decorticated pulp highly depended on concave clearance rather than other factors. Maximum decorticating efficiency 98.97% and minimum pulp loss of 1.03% were achieved at drum beater speed of 850 rpm and concave clearance of 1mm. The production cost of the decorticator was found to be 28,322.00 Birr. The total operating cost of the decorticator estimated to be, 48,925.38 Birr and the payback period and benefit-cost ratio of the prototype decorticating machine were estimated to be 0.90 years and 1.64, respectively.

Based on previous results indicating excessive milling loss inherent in rice milling process in E... more Based on previous results indicating excessive milling loss inherent in rice milling process in Ethiopia, a study was conducted to evaluate the effects of parboiling treatment on three released (Gumara, Kokit, and Tigabe) and one local (X-Jigna) rice varieties. Parboiled and un-parboiled rice samples were milled using small and portable Rice Whitener (SRW). The result has indicated that the response for Parboiling is variety specific. But, in general, parboiling resulted in improved milling quality in most of the studied varieties. An overall increase in Milling yield (from 62.70 to 65.83%), milling recovery (from 79.50 to 83.97%) and whole grain yield (from 27.83 to 37.68%), was observed while milling loss has reduced (from 16.50 to 12.50%) by this treatment. Likewise, parboiling reduced machine throughput and output. Milling qualities of Gumara and Tigabe and, to some extent, Kokit varieties had been improver and that of X-Jigna declined when milled parboiled. Tigabe and Kokit had...

Springer Geography, 2015

Effect of filter press mud (FPM) application on nutrient availability in Aquert and Fluvent soils... more Effect of filter press mud (FPM) application on nutrient availability in Aquert and Fluvent soils at Wonji-Shoa Sugarcane Plantation, located at central part of the East African Rift Valley, was studied during the 2003/04 growing season. The rate of FPM application was 0, 60 and 120 ton/h. Field monitoring was made for ninety days. As per the management practice of the Sugar Estate, the Aquert soil was green manured with Crotalarea junceae prior to the treatment application. Soil samples were collected and analyzed every fortnight for organic carbon (OC) and available N. Available P, exchangeable bases, Fe, and Mn content of the soil were monitored at the beginning and end of the experiment. Incorporation of FPM significantly increased the OC content in both soils. Nonetheless, the accumulation of OC was more in Aquert than Fluvent soils, due to the initial higher OC obtained from Crotalatea j., higher clay content and moist condition of the Aquert soil. The application of FPM promoted the available N though the availability of N ion, however, in both soils, the content declined during the first 45 days after application. Gradually, significant increase in the available N was observed (starting from 45th day of application up to the 90th day). This indicates that FPM having C/N ratio of 27 resulted in priming effect. The trend analysis made indicated that proportional increase in available P can be obtained with increasing rate of FPM application, though available K was found to be lower in FPM treated soils. The application of FPM buffered (reduced) the soil pH to 7.6. The highest rate of FPM application (120 ton/ha) slightly improved the soil electrical conductivity (EC). Furthermore, the study indicated that the application of FPM had the ability to reduce the soils exchangeable Na content. Thus, FPM has the potential to amend sodicity and abnormal pH of soils. However, it was noted that the application of FPM had reduced Fe/Mn ratio indicating its possible ability to slow down or reduce Fe uptake by plants. Therefore, prior checking for available K and Fe has to be made to ensure unnecessary consequences on sugarcane plants.

Water Resources Management, 2014

Floodwater management and sedimentation are the key issues which should be considered during the ... more Floodwater management and sedimentation are the key issues which should be considered during the development of new, or improvement of existing, spate irrigation schemes. The traditional intakes are superior in their site location, flexibility, and sediment-control capability. However, they have been frequently damaged by floods resulting in loss of continuous irrigation supply. The modern structures, albeit strong enough to withstand the impact force of the largest floods, suffer from large sedimentation problems. Farmers of Aba'ala Plain have been struggling with sedimentation and floodwater-management problems associated with their modern and traditional intakes. The objective of this research is, thus, to study the existing flood and sediment management practices and identify alternative options for optimum management of floods and sediments in the Aba'ala Plain, Afar. Aba'ala is the largest plain in the arid lowlands of Ethiopia where a combination of traditional, improved and modern spate irrigation systems are practiced. Extensive fieldwork was undertaken leading to measurement and collection of primary data including discharge, sediments and river cross sections. Interviews and focal group discussions were also employed and these generated deeper insights into O&M activities. In addition, Alluvial Friction Predictor and Sand Transport Predictor of SHARC model were employed to generate sediment concentration of the floodwater. Delft3D, a hydrodynamic model, has been used to simulate flow patterns and sedimentation under the existing condition and for different improvement options. For the existing condition (scenario-I), results of the model simulation showed high sediment deposition and low floodwater abstraction rate. Consequently, only 41 and 23% of the command areas under the modern and traditional intakes can be fully irrigated during the bad flood season. The high intake diversion rate and the reduced sedimentation around the intake were achieved with the improvement options under scenario-II (four consecutive bed stabilizers, a 30 m guiding wall upstream of the modern intake and reinforcement of the traditional intake). However, this scenario has a potential to cause conflict between upstream and downstream users as the result showed a decline of water level (15 cm) at the downstream intake. Therefore, scenario-III is recommended for a maximum floodwater diversion and minimum sediment deposition with a fair share of water between upstream and downstream intakes. This scenario would consist of open gabion reinforced multiple intakes with a 78 m long guide wall upstream of the modern intake, a 30 m long guide wall upstream of the traditional intake and a series of four bed stabilizers upstream of the diversion point.

Nile River Basin, 2014

ABSTRACT

Springer Geography, 2015

Soil compaction on sugar cane fields has been found to reduce yield and productivity. Influence o... more Soil compaction on sugar cane fields has been found to reduce yield and productivity. Influence of filter press mud (FPM), a residue obtained by filtration of the mud in cane juice clarification process, on compaction and consistency of Fluvent and Aquert soils was investigated on experimental plots. For compaction study, standard proctor test was employed and consistency parameters [liquid limit (LL) by drop cone method and plastic limit (PL)] were determined. Infield penetration resistances and basic infiltration were measured. The maximum dry bulk densities (MDBD) of the soils after standard proctor compaction were 1.42 and 1.30 g cm−3 at 28 and 29 % critical moisture content (CMC), respectively. For Fluvent, the CMC was at PL and on Aquerts at 66 % of the PL. For both soils, total porosity, degree of saturation and air-filled porosity were significantly improved by FPM application only at the CMC. Moreover, FPM increased cone index (CI) of the soil. On all experimental fields, the CI was below the critical value, but CI increment was observed around 20–25 cm depths after tillage. Basic infiltrations of the soils were 6.5 for Fluvent and 4.4 mm/h for Aquert, but effect of FPM was statistically non-significant.

Soil water infiltration is one of the most important processes affecting the volume, transport ro... more Soil water infiltration is one of the most important processes affecting the volume, transport route and water quality of agricultural drainage. Tillage method and depth have also effects on the ability of soil to store water and the furrow irrigation hydraulics of irrigated fields. A study was conducted to evaluate the effect of tillage method and depth on furrow irrigation hydraulics and soil water storage during the dry season at Dire Dawa, Eastern Ethiopia. Treatments in the study included were chisel, moldboard and disk ploughing to 150 mm and 250 mm depths; and “Maresha” (local plough). Data obtained through field measurement and/or observations and laboratory analysis included soil data, irrigation water, advance and recession times, inflow–outflow volumes, available soil moisture, and infiltration rate at each irrigation event. Extending tillage depth from 150 mm to 250 mm significantly increased irrigation infiltration (mm) from 34 to 38%, increased irrigation water advance time from 55 to 75%, increased application efficiency from 33 to 55%, and increased saturated hydraulic conductivity from 23 to 48%; and significantly decreased tail water ratio and distribution uniformity (p < 0.05) in the first two irrigations, but had little effect during the successive irrigations.

Abstract Tillage practices and depth of plow play an important role in altering the porosity and ... more Abstract Tillage practices and depth of plow play an important role in altering the porosity and infiltration capacity of soils and hence surface runoff and soil water availability. A study was conducted to evaluate the effect of tillage method and depth on grain yield and irrigation water use efficiency (IWUE) during the dry season at Dire Dawa, eastern Ethiopia. Treatments for this study included were chisel plow at 150 and 250 mm depth (CH 150 and CH 250 ), and disk plowing to 150 mm and 250 mm depths (DP 150 and DP 250 ); moldboard plow (MB 150 and MB 250 ) and “Maresha” (local plowing) (LP). Grain yield was determined by taking samples from three sections of the central furrow. Grain yields were adjusted to 10% moisture content. It was found that tillage method did not significantly affect the average grain and biomass yield and IWUE of grain and biomass. The grain yield for tillage method treatments averaged from 5325 kg/ha for local plow to 5839 kg/ha for disk plow. The effect of depth of plow on grain yield (kg/ha) ranges from 392 to 7108 for MB 150 and DP 250 , respectively. The IWUE (grain, kg/ha cm) for tillage depth treatments averaged from 16.73 for DP 150 to 30.90 for DP 250 , and their respective IWUE (biomass, kg/ha cm) averaged from 95.4 (MB 150 ) to 124.6 (CH 250 ).