95 research outputs found
Rethinking Educati. in Ethiopia. Tekeste Negash, Nordiska Afrikainstitutet, Uppsala, 1996, 118 pages .
No full textTekeste Negash, the author of The Crises ofEthiopia Education: some implications fornation building (t 990), has' recently comeout with a book, Rethinking Education inEthiopia. He analyses educational issues andpolices in Ethiopia from the historical andcontemporary perspectives in relation to thedevelopment of the country. He alsoforwards recommendations some. of whichare in fact controversial
Successful vegetative propagation techniques for the threatened African pencil cedar (Juniperus procera Hoechst. ex Endl.)
No full textMapping of ferric (Fe3+) and ferrous (Fe2+) iron oxides distribution using ASTER and Landsat 8 OLI data, in Negash Lateritic iron deposit, Northern Ethiopia
No full textIron plays an important role in industrial and engineering fields development of a country and as such there is an enormous demand for iron in Ethiopia. However, a search for this valuable primary mineral resource exploration remains challenging and costly. Therefore, this study aims to map iron oxide minerals using Landsat-8/operational land imager (OLI) and advanced space-borne thermal emission and reflection (ASTER) satellite imagery in Negash Lateritic iron deposit, Northern Ethiopia to ease the costs and reduce the time. Different image processing techniques such as band ratio, selective principal component analysis, linear spectral unmixing, and mixture-tuned matched filter were used to produce iron oxide maps. Minimum noise fraction (MNF), pixel purity index (PPI), and N-dimensional visualizer were also applied to extract endmembers in the automated spectral hourglass wizard. In addition to this, the enhanced image thresholding and scatter plot were used to map the potential areas. Ferric iron oxide band ratio of ASTER mapped maximum area of 62.1 km2 followed by a laterite band ratio of ASTER covering 57.8 km2. The result was validated using existing iron oxide polygons and the outcome obtained from selective PCA shows a strong match with the existing iron oxide polygons. The sub-pixel mapping techniques show poor accuracy in mapping goethite and hematite relative to the pixel level. Thus, it is evident from the results that ASTER mapped better than Landsat 8 OLI for band ratios of selective PCA, unmixing, MTMF, and mineralized areas while characterizing with limited fieldwork
Germination responses of Croton macrostachyus (Euphorbiaceae) to various physico-chemical pretreatment conditions
No full textAbstractCroton macrostachyus Hochst. ex Del. (Euphorbiaceae) is a multipurpose, deciduous, and medium sized tree of pantropic occurrence. Because the species has numerous useful qualities (e.g., establishment and growth in disturbed sites, drought tolerance, fast growth rate, copious litter/necromass production, suitability for agroforestry, and ability to attract avian frugivores), its speedy restoration has become increasingly critical. Germination studies were therefore conducted on seeds pooled from five widely located provenances with a view to supporting efforts geared toward the speedy propagation and restoration of this valuable tree species. Seed pretreatments were achieved using various dilution levels of plant-derived smoke–water (1:1, 1:10, 1:100 and 1:1000), as well as gibberellic acid (GA3) or potassium nitrate (KNO3) ranging in concentration from 0.1 to 100μmol. The control was to use distilled water for seed pretreatment. Seeds were germinated under either illuminated (ca 60μmolm−2s−1; cool-white fluorescent lamp) or non-illuminated conditions. Experiments on the impact of seed storage durations, as well as storage temperatures were also conducted. The study found that germination percentage (GP: ca 90%), and mean germination time (MGT: 14days) were significantly (P<0.001) better when seeds were pretreated with smoke–water and germinated under non-illuminated conditions, than when these were pretreated with various concentrations of GA3 or KNO3 (GP and MGT of ca 65% and 20days, respectively). Germination percentage (GP) and germination vigor (GV) declined with increasing storage-time for all storage temperatures, but GV's decline was faster for seeds stored at 22°C than for those stored at 5 and 15°C. On the other hand, mean germination time (MGT) increased significantly (P<0.01) with seed storage-time of up to 8months at 5, 15, and 22°C, but the increase was more marked for seeds stored at 22°C than for those stored at 5 and 15°C. From these investigations, it is concluded that germination of C. macrostachyus seeds through use of smoke–water is faster, cheaper, and technically less demanding, compared to that of either GA3 or KNO3. The study also concludes that C. macrostachyus is intermediate between orthodox and recalcitrant seeds, and that it is non-photoblastic
Asexual propagation of Juniperus procera from Ethiopia: a contribution to the conservation of African pencil cedar
No full textRecommended from our members
Major changes made by the revised Family Law of 2000 regarding women's rights and the need to enhance awareness of the society /
No full textMeasuring Extent of Restoration Using Coffee (Coffea arabica L.) as a Bioassay Plant Species
No full textThis study was undertaken as part of the ongoing biological restoration with the objective of measuring extent of restoration over a degraded landscape using coffee plants (Coffea arabica L.) as bioassay organisms. The coffee plants were established beneath Acacia abyssinica Hochst.ex.Benth., Croton macrostachyus Hochst. ex Del. and Euclea divinorum Hiern. stands which were established 9-11 years ago in a degraded landscape. All the vegetative and reproductive data were collected on randomly selected 3- to 5-year-old coffee plants. The results showed that mean number of lateral stem branch, leaves, leaf area and internodal lengths were significantly (P<0.05) greater for those established beneath the shades of E. divinorum for 3-4 years, compared to those beneath the C. macrostachyus and A. abyssinica shades. Further, key biological indices such as mean number of fruiting nodes, berries per node, mature red berries harvested per plant, fresh weight of berries, size and weight of beans, bean to berry weight ratio, weight per 1000 beans and coffee bean yield (g/tree) were all significantly (P<0.05) higher for coffee plants established under the shade of A. abyssinica than those established under the shades of C. macrostachyus and E. divinorum, and on less-restored area. The levels of available phosphorous, total nitrogen and organic carbon were significantly (P<0.05) 54, 39 and 56 % higher, respectively, in the sites that were in the process of restoration than adjacent, non-restoring sites. This study showed that restoring native plants over degraded landscapes restores essential nutrient elements and favorable environmental conditions for the successful development productivity of economically useful crops such as C. arabica. Keywords: coffee reproductive traits, degraded landscapes, Ethiopia, indigenous trees, restoration bioassay
Effects of Blended Fertilizer Rate and Time of Application on Growth and Yield of Sugarcane Ratoon Crop at Arjo-Sugar Factory, Western Ethiopia
No full textLack of appropriate agronomic practices related to fertilizer management is a major constraint to enhancing sugarcane yield in Ethiopia. The effect of optimum rate and time of blended fertilizer application on yield and quality of ratoon commercial crop is not known at Arjo Didessa Sugar factory. Therefore, the field experiments were conducted with the objectives of assessing the effect of blended fertilizer at different rate and time of application on Ratoon sugarcane growth and yield of cane. The treatments consisted of eight levels of blended fertilizer with N (0, 150, 111N, 200 and 103N, 250 and 94N, 300 and 85N, 350 and 76.4N, 400 and 68N kg ha-1 and recommended fertilizer rate) and two times of application (one and two month after harvest). The field experiments were laid out as Randomized complete block design in a factorial arrangement and replicated three times. A sugarcane cultivar named N-14 was used as a ratoon material. Analysis of variance of the data revealed that the blended fertilizer application rate had significant effect on ratoon weight per stalk, node number, plant height, node length and cane yield sugar yield. Blended fertilizer rate and time of application and their interaction showed only highly significant on stalk girth and stalk population and interaction was significant effect on weight per stalk and node length at the time of harvest. However, application of blended fertilizer at different time and their interaction on plant height, cane yield and node number did not showed significant effect. Blended fertilizer treatment with the rate of 250kg ha-1 blended fertilizer mixed with 94kg N ha-1 at one month after harvest resulted in higher ratoon cane weight per stalk, stalk girth, cane yield, sugar yield, node length, stalk population and node number. Therefore, highest cane yield was recorded at late application time of blended fertilizer at lower dose and higher dose of nitrogen. Therefore, treating the ratoon cane by 250kg ha-1 BLF with 94kg N ha-1 at one month after harvest had evidently the advantage of improving ratoon cane growth and yield performanc
Effects of Blended Fertilizer Rate and Time of Application on Growth and Yield of Sugarcane Ratoon Crop at Arjo-Sugar Factory, Western Ethiopia
No full textOriginal Article In vitro Regeneration of Taverniera Abyssinica A. Rich: A Threatened Medicinal Plant
No full textIn vitro germination, callus induction and plant regeneration has been established for
dingetegna, Taverniera abyssinica. The best in vitro germination of seeds and vigorous
seedlings growth as a prerequisite for the development of tissue culture methods was
obtained on Murashige and Skoog medium supplemented with 12 g 1-1
phytoagar
without sucrose. Light green compact calli from node, petiole and shoot meristem
explants were efficiently induced on Gamborg medium containing 0.90 or 1.80 µM
dichlorophenoxyacetic acid (2,4-D) combined with 2.22 µM 6-benzylaminopurine (BAP),
and supplemented with 30 g 1-1
sucrose and 5 g 1-1
phytagel. Callus initiation from shoot
meristems and nodes was faster and occurred with a higher frequency than callus
initiation from petiole and leaf segments (P<0.05). A high frequency of shoot
regeneration (100%) was obtained upon transfer of calli onto regeneration medium
containing 8.88 µM BAP combined with 1.14 µM indoleacetic acid (IAA). Regenerated
shoots were transferred to rooting medium, which turned out to be optimal when half
strength B5 medium was supplemented with 9.84 µM indolebutyric acid (IBA). Upon
transfer to glasshouse, 86% survived and grew vigorously. The development of in vitro
regeneration protocol for T. abyssinica provides the possibility to preserve endangered
germplasm from the increasingly devastating man-made environmental conditions.
Moreover, the method established can be used for micropropagation and genetic
improvement of this medicinally important species
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