Entity

Time filter

Source Type


Aerts R.,Catholic University of Leuven | Aerts R.,Mekelle University | Van Overtveld K.,Catholic University of Leuven | November E.,Mekelle University | And 25 more authors.
Science of the Total Environment | Year: 2016

In the central and northern highlands of Ethiopia, native forest and forest biodiversity is almost confined to sacred groves associated with churches. Local communities rely on these 'church forests' for essential ecosystem services including shade and fresh water but little is known about their region-wide distribution and conservation value. We (1) performed the first large-scale spatially-explicit assessment of church forests, combining remote-sensing and field data, to assess the number of forests, their size, shape, isolation and woody plant species composition, (2) determined their plant communities and related these to environmental variables and potential natural vegetation, (3) identified the main challenges to biodiversity conservation in view of plant population dynamics and anthropogenic disturbances, and (4) present guidelines for management and policy. The 394 forests identified in satellite images were on average ~ 2 ha in size and generally separated by ~ 2 km from the nearest neighboring forest. Shape complexity, not size, decreased from the northern to the central highlands. Overall, 148 indigenous tree, shrub and liana species were recorded across the 78 surveyed forests. Patch α-diversity increased with mean annual precipitation, but typically only 25 woody species occurred per patch. The combined results showed that >. 50% of tree species present in tropical northeast Africa were still present in the 78 studied church forests, even though individual forests were small and relatively species-poor. Tree species composition of church forests varied with elevation and precipitation, and resembled the potential natural vegetation. With a wide distribution over the landscape, these church forests have high conservation value. However, long-term conservation of biodiversity of individual patches and evolutionary potential of species may be threatened by isolation, small sizes of tree species populations and disturbance, especially when considering climate change. Forest management interventions are essential and should be supported by environmental education and other forms of public engagement. © 2016 Elsevier B.V. Source


Adgo E.,Bahir Dar University | Adgo E.,Tottori University | Teshome A.,Amhara Agricultural Research Institute | Mati B.,Improved Management of Agricultural Water in Eastern and Southern Africa IMAWESA
Agricultural Water Management | Year: 2013

Over the last three decades, many soil and water conservation projects have been implemented in various parts of eastern and southern Africa to control land degradation, and improve land productivity, especially under 'catchment approach' initiatives of the 1980s. In Ethiopia, many of these soil conservation projects were implemented following the severe drought of 1974. To capture long-term impacts of these initiatives, a study was conducted in Anjenie Watershed of Ethiopia, assessing fanya juu terraces and grass strips constructed in a pilot project in 1984, and which are still functional 25 years later. Data were collected from government records, field observations and questionnaire surveys administered to 60 farmers. Half of the respondent had terraced farms in the watershed former project area (with technology) and the rest were outside the terraced area (without technology). The crops assessed were teff, barley and maize. Cost-benefit analyses were used to determine the economic benefits with and without terraces, including gross and net profit values, returns on labour, water productivity and impacts on poverty.The results indicated that soil and water conservation had improved crop productivity. The average yields on terraced fields for teff, barley and maize were 0.95tha-1 (control 0.49), 1.86tha-1 (control 0.61), and 1.73tha-1 (control 0.77), respectively. The net benefit was significantly higher on terraced fields, recording US$ 20.9 (US$ -112 control) for teff, US$ 185 (US$ -41 control) for barley and US$ -34.5 (US$ -101 control)ha-1yr-1 for maize, respectively. The returns on family labour were 2.33, 1.01 and 0.739US$man-day-1 for barley, teff and maize grown on terraced plots compared to US$ 0.44, 0.27 and 0.16man-day-1 for without, respectively. Using a discount rate of 10%, the average net present value (NPV) of barley production with terrace was found to be about US$ 1542 over a period of 50 years. In addition, the average financial internal rate of return (FIRR) was 301%. Other long-term impacts of terracing included farmers' growing of maize on terraced fields as a result of water conservation. Currently, farmers also grow barley on terraced fields for two crop seasons per year unlike the experiences on farms without terraces. Household incomes and food security had improved and soil erosion drastically reduced. Many farmers had adopted terracing doubling the original area under the soil conservation pilot project and consequently improving environmental conservation in the watershed. © 2012 Elsevier B.V. Source


Abebe T.,Amhara Agricultural Research Institute | Wongchaochant S.,Kasetsart University | Taychasinpitak T.,Kasetsart University
Kasetsart Journal - Natural Science | Year: 2013

Potato starches isolated from 25 different varieties grown at three different locations in the Amhara region of Ethiopia in 2011 were studied to determine their variation based on amylose content (AMC) and amylopectin content (APC), and pasting properties by iodine colorimetry and Rapid Visco Analyzer procedures, respectively. The results revealed highly significant (P < 0.01) differences between cultivar and location. The mean values for the AMC and APC ranged from 20.86% (Jalene) to 30.58% (Ater Abeba), and 69.42% (Ater Abeba) to 79.14% (Jalene), respectively. The mean AMC index of locations ranged from 24.50% to 26.24% for the Adet and Debretabor sites. The peak viscosity (PV), hot paste viscosity (HPV), breakdown viscosity (BDV), cool paste viscosity (CV) and setback viscosity (SBV) ranged from 225.10 to 426.72, 135.01 to 191.83, 56.47 to 259.32, 173.68 to 247.51 and 27.17 to 68.15 Rapid Visco units (RVU), respectively, while the pasting time (PT) and pasting temperature (Ptemp) ranged between 3.35 to 4.91 minutes and 68.16 to 70.89 °C, respectively. Correlation among starch properties showed significant (P < 0.01 and P < 0.05) associations except for PV with CPV and HPV with BDV and SBV. The highest PV (538 RVU), HPV (207 RVU), BDV (363 RVU), and CV (265 RVU) values were recorded at the cool Debretabor site. Thus, the study revealed the significant genetic variation present among varieties with regard to the starch chemical composition and pasting properties and the effects of growing location on these properties. Source


Abebe T.,Amhara Agricultural Research Institute | Wongchaochant S.,Kasetsart University | Taychasinpitak T.,Kasetsart University
Kasetsart Journal - Natural Science | Year: 2013

Specific gravity (SG) is the measure of choice for estimating dry matter (DMC) and starch content (SC) and ultimately for determining the processing quality of potato varieties. Evaluation of the SG of 25 potato varieties was carried out at three distinct locations in the Amhara region of Ethiopia with the main objectives of determining their culinary quality and most suitable areas of production. The varieties were planted in a 5 × 5 balanced lattice design of six replications during the 2011 rainy season. The results of the data analysis showed highly significant (P < 0.01) genotypic and location differences and significant (P < 0.05) genotype × environment interactions. The pooled SG values ranged from 1.058 to 1.102. The SG of tubers of the improved variety Belete was the highest while that of Menagesha was the lowest. Furthermore, the SG values for varieties grown at Debretabor were higher than those for the corresponding varieties grown at Adet and Merawi. The DMC and SC were computed based on the SG and showed significant (P < 0.01) genotypic variability. The highest DMC and SC were also obtained at Debretabor; thus, it is an ideal location to grow potatoes for high DMC and starch accumulation. Additive main effects and multiplicative interaction analysis identified CIP-392640.524, Zengena, Jalenie and Belete as stable genotypes with SG values above average. Source


Steenhuis T.S.,Cornell University | Steenhuis T.S.,Bahir Dar University | Hrncir M.,Czech Technical University | Poteau D.,Cornell University | And 9 more authors.
Vadose Zone Journal | Year: 2013

Since Hewlett and Hibbert's publication in 1967, there has been a slow recognition that saturated excess runoff is the main runoff mechanism in vegetated watersheds. Yet, most pedotransfer functions for predicting runoff are based on infiltration excess runoff. We, therefore, developed a simple pedotransfer function to predict saturation excess runoff, using data from eight watersheds on three continents. The runoff response was very similar for all watersheds, despite differences in climate, size, topography, and land use. Direct storm runoff occurred after a threshold amount of rainfall was exceeded. Runoff was linearly related to rainfall depth, indicating that a nearly constant proportion of the watershed was the source area. Size of source areas decreased with increasing depths of soils. The rainfall threshold was strongly dependent on the initial moisture conditions. The developed pedotransfer function for saturation excess runoff was used to predict water level fluctuation of two terminal lakes on the Caribbean Islands over a 25- to 30-yr period with the rainfall threshold computed following Thornthwaite-Mather and baseflow from the remaining part of the watershed employing a linear reservoir model. Taking the simplicity of the prediction technique with only four calibrated parameters into account, lake levels were predicted reasonably well to very good, including the rise in the lake level in the last 10 yr when the climate in the region became wetter. It is expected that the linear relationship of rainfall and runoff holds for storms lasting several days and can simplify flood predictions. © Soil Science Society of America, All rights reserved. Source

Discover hidden collaborations