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Tilahun S.A.,Cornell University | Tilahun S.A.,Bahir Dar University | Guzman C.D.,Cornell University | Zegeye A.D.,Bahir Dar University | And 7 more authors.
Hydrology and Earth System Sciences | Year: 2013

Erosion modeling has been generally scaling up from plot scale but not based on landscape topographic position, which is a main variable in saturation excess runoff. In addition, predicting sediment loss in Africa has been hampered by using models developed in western countries and do not perform as well in the monsoon climate prevailing in most of the continent. The objective of this paper is to develop a simple erosion model that can be used in the Ethiopian Highlands in Africa. We base our sediment prediction on a simple distributed saturated excess hydrology model that predicts surface runoff from severely degraded lands and from bottom lands that become saturated during the rainy season and estimates interflow and baseflow from the remaining portions of the landscape. By developing an equation that relates surface runoff to sediment concentration generated from runoff source areas, assuming that baseflow and interflow are sediment-free, we were able to predict daily sediment concentrations from the Anjeni watershed with a Nash-Sutcliffe efficiency ranging from 0.64 to 0.78 using only two calibrated sediment parameters. Anjeni is a 113 ha watershed in the 17.4 million ha Blue Nile Basin in the Ethiopian Highlands. The discharge of the two watersheds was predicted with Nash-Sutcliffe efficiency values ranging from 0.80 to 0.93. The calibrated values in Anjeni for degraded (14%) and saturated (2%) runoff source area were in agreement with field evidence. The analysis suggests that identifying the runoff source areas and predicting the surface runoff correctly is an important step in predicting the sediment concentration. © 2013 Author(s).

Goshu G.,Bahir Dar University | Tewabe D.,Amhara Regional Agricultural Research Institute | Adugna B.T.,Bahir Dar University
Ecohydrology and Hydrobiology | Year: 2010

The distribution of Lake Tana fish species was studied from January 2000 to December 2003. Samples were collected monthly using gill-nets of 60, 80, 100, 120 and 140 mm stretched mesh size. Labeobarbus spp., Oreochromis niloticus, Claris gariepinus and Varicorhinus beso are commercially important fish species and form 77%, 13%, 9% and 1% of the pooled experimental fish catch. There was significant variability among years and sampling sites encompassing both temporal and spatial aspects. Population densities of Labeobarbus spp. and V. beso were significantly declining, in contrast, the abundance of O. niloticus and C. gariepinus did not change. The most likely explanations for the decline in Labeobarbus spp. are the increase of the commercial gill-net fishery targeting their spawning aggregations in the river mouths, use of poisonous plant materials and the increasing trend of the dis-connectivity and channelisation of rivers. The results stress the need for urgent development of a management plan focusing on ensuring river connectivity, fishing effort and gear restrictions, and control in the river mouths and major tributaries during the breeding seasons.

Chanie T.,Bahir Dar University | Chanie T.,Amhara Regional Agricultural Research Institute | Collick A.S.,University Park | Adgo E.,Bahir Dar University | And 3 more authors.
Journal of Hydrology and Hydromechanics | Year: 2013

Eucalyptus is the tree of choice for wood production by farmers in Ethiopia. Although there are many claims about its harmful effect on ecology and water availability, little actual research exists. The main objective of this study was, therefore, to study the extent of harm of Eucalyptus on the ecosystem. This study was conducted at the Koga Watershed near Lake Tana in Ethiopia. Twenty-five farmers were interviewed and a field experiment with three replications was carried out to quantify the effect of Eucalyptus on various soil physical and chemical properties and maize crop measurements and to compare bulk density, soil moisture contents, maize crop counts and shading effects in fields bordered by Eucalyptus and Croton macrostachyus. Our results show that Eucalyptus decreased both soil nutrients and maize yields within 20 m of the trees. Although moisture content was not affected during the monsoon, it decreased faster within 30 m of the Eucalyptus trees than elsewhere. Soils become water repellent, too. Local farmers' perception agreed with our experimental findings and indicated that Eucalyptus trees are exhausting the once productive land. They also reported that Eucalyptus dries up springs. Despite this, the growers insist on planting Eucalyptus because of its cash income.

Abate E.,University of KwaZulu - Natal | Abate E.,Amhara Regional Agricultural Research Institute | Hussein S.,University of KwaZulu - Natal | Laing M.,University of KwaZulu - Natal | Mengistu F.,Amhara Regional Agricultural Research Institute
Australian Journal of Crop Science | Year: 2013

Tef [Eragrostis tef (Zucc.) Trotter] is the most widely produced and consumed cereal crop in Ethiopia. It is a gluten-free crop with growing popularity worldwide. Unlike most globally important cereals, tef has not yet been bred for tolerance to soil acidity and to aluminium toxicity. This experiment was conducted to assess the quantitative responses among some grain and pasture varieties of tef. Strongly acidic soil (pH 3.94 and acid saturation of 78%) was used to evaluate the tef varieties. A highly Al-tolerant weeping love grass [Eragrostis curvula (Schrad.) Nees] variety, Ermelo, was used as a check. A randomized complete block design (RCBD) with 4 replications was used to evaluate the materials under limed and unlimed conditions. Measurements were taken on different root and shoot parameters. The result indicated the presence of genetic variability among the tef varieties for root length, shoot length, root dry weight and shoot dry weight. All the tef varieties were inferior to the variety Ermelo of E. curvula in their Al tolerance. The brown seeded tef varieties consistently showed better Al-tolerance than the white seeded ones. A similar pattern was also observed for tolerance indices, which were computed as ratio of each parameter under unlimed versus limed condition. Highly significant correlations (r>0.9) were observed for all the parameters used to assess Al-tolerance in this experiment. This first systematic work demonstrated the presence of genetic variability for tolerance to soil acidity and Al-toxicity within tef varieties. This variability suggests the possibility to launch strategic breeding of the crop with specific adaptation to acid soil prone areas.

Teshome A.,Wageningen University | Teshome A.,Amhara Regional Agricultural Research Institute | de Graaff J.,Wageningen University | Ritsema C.,Wageningen University | Kassie M.,International Maize and Wheat Improvement Center
Land Degradation and Development | Year: 2016

Land is a scarce resource in the highlands of Ethiopia. Its sustainable use is highly affected by bio-physical and institutional factors. The purpose of this research is to investigate farmers' perceptions about land quality, land fragmentation and tenure systems and their influences on sustainable land management (SLM) investments in the North Western Ethiopian Highlands. The study is based on a detailed farm survey among 300 households and 1,700 parcels in three watersheds. Simple descriptive statistics were applied to analyse the perception of farmers about land-related factors. A multivariate probit (MVP) model was used to analyse the effect of land-related factors on the interdependent investment decisions of SLM practices (Bunds, Compost/Manure and Fertilizer) using a multiple parcel-level survey. The study shows that on average, sample households managed 4·54 parcels in different locations with an average parcel size of 0·26ha. The MVP model analysis indicates that farmers invest a combination of practices at parcel level by considering substitution and complementarity effects of the practices. The results also reveal how land quality (e.g.slope and soil fertility status), land fragmentation (parcel size and distance of parcel from homestead) and tenure arrangements influence farmers' investments in SLM practices. The overall results indicate that farm land attributes promote or hinder investments, and tenure systems regulate the decisions about investments. Policy makers should take into consideration these various land-related factors in designing and implementing SLM policies and programmes. © 2016 John Wiley & Sons, Ltd.

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