1,720,964 research outputs found
Review of Potato Agronomic Research in Central highlands of Ethiopia: Achievements and Future Prospects
Get PDFThe suboptimal agronomic techniques practiced by potato growers in Ethiopia are undoubtedly one of the contributing factors to the existing low average national yield. Agronomic studies have been undertaken by different research centers and higher learning institutions to develop a package of optimum Agronomic management practices, together with improved potato varieties. Agronomic research at Holetta, Adet and Bako Agricultural Research Centers and various universities were carried out for more than two decades with the objectives to alleviate production constraints of potato in different parts of the country for various agro-ecologies for smallholder farmers and thereby increase the production and productivity of potato. Thus, experiments were carried out on agronomic research such as planting dates, planting depth and method of planting, inter and intra row spacing, planting depth and intra row spacing, seed tuber size & plant population density and number of hilling during the growing period. These experiments were carried out at different agro-ecological zones, via mid altitude and high altitude areas of the country. Moreover, fertilizer rate and time of applications, nitrogen fertilizer and planting density, and integrated use of organic and inorganic fertilizers application to see their effect on potato yield and quality for seed and ware potatoes productions comprise the major component of the agronomic/physiology research. In addition, agronomic practices such as intercropping, dates of dehaulming and vermicompost were carried out. Therefore, to boost the production and productivity of potato for food security and income generation in the country the appropriate use of recommended agronomic practices should be crucial.
Keywords: Potato, Agronomy, Nitrogen & Phosphorus, INM, Vermicompost, Ethiopi
Participatory Research for Integrated Nutrient Management (INM): The Case of Potato Production in Central Highlands of Ethiopia
Get PDFBackground and Objective: Integrated use of organic and inorganic fertilizers can improve soil fertility and potato productivity. The study was initiated in the central highlands of Ethiopia to determine the influence of INM on potato tuber yield through FRG and FFS extension approach. Materials and Methods: Integrated Nutrient Management of potato was evaluated through both Farmers Field School and Farmers Research Group participatory research methods in Jeldu, Dendi, Welmera, and Alemaya districts during 2004-2006 to investigate the influence of inorganic fertilizer, compost and their mixture application on yield, yield components of potato. The treatments included three improved potato varieties, nationally recommended fertilizer rate of (165 kg/ha Urea and 195 kg/ha DAP) and recommended compost at a rate of 10 t/ha. The experiment was laid out as a randomized complete block design with three replications. Results: At all locations, regardless of potato varieties, application of inorganic fertilizer gave significantly highest yield followed by the mixture of organic and inorganic fertilizers. Application of inorganic fertilizer gave 6% over the control while inorganic fertilizer application gave 45% yield advantage over the control. The mixture of organic and inorganic fertilizer gave 20% less tuber yield as compared to inorganic applied treatment but gave 19% and 25.3% more yields over the organic and the control, respectively. Inorganic fertilizer gave 37% more tuber yields over the organic treatment and 16% more yield over the mixed fertilizer treatment. However, the mixture of organic and inorganic fertilizers gave 18.1% over the organic fertilizer applied treatment. Potato variety Degemegn gave the highest tuber yields in both seasons 2005 and 2006 as compared to variety Jalenie and Menagesha. In general, application of inorganic fertilizers leads to higher tuber yields in all locations and in all varieties except the yield obtained at Jeldu site on 2005. Conclusions: Regarding the treatments, inorganic fertilizer was the top yielder in most of the locations and varieties and mixed fertilization was the second followed by organic composting. Hence resource poor farmers could adopt the mixed approach which is less expensive. Therefore, use of compost as fertilizers will have positive effects beyond the potato season due to its slow releasing of nutrients and will reduce the cost of production giving comparable yields with the one acquired using inorganic fertilizers. Keywords: Integrated Nutrient Management, Farmer Research Group, Farmer Field School, Soil fertility, Potat
Integrated Late Blight Management for Potato: The Case of FFS and FRG in Central Highlands of Ethiopia
Get PDFPotato is the fastest growing staple food crop and source of cash income for smallholder farmers in Ethiopia. Potato production was almost impossible during the rainy season in the central high lands of Ethiopia due to potato late blight diseases. Recently, the introduction of late blight tolerant varieties changed the trend and farmers were able to overcome their food insecurity problem during the long rainy season. A participatory potato technology development and dissemination process was undertaken in the central highlands of Ethiopia in four districts of Oromia regional states using Integrated Disease Management /IDM/ for Potato late blight disease. A total of thirteen FFSs and thirty six FRGs were organized to conduct the activity. Thus, participatory research methods of through farmer’s field school (FFSs) and farmers research group (FRGs) were organized to evaluate and promote the technologies. The number of participant farmers in each FFS and FRG included an average of 25 and 15, respectively. The experiment was laid in split plot design putting fungicide spray as main plot and potato clones as sub-plot. To see the difference in their reaction to late blight disease a fungicide (Ridoml MZ 62.3% WP) was sprayed twice at a rate of 2 kg/ha. The analysis of variance (ANOVA) revealed that there was a highly significant difference (P<0.001) on yielding ability among the clones evaluated. Thus, mean separation test was carried out using least significance difference (LSD) test procedure. The highest yield was obtained from the clone CIP-392650.516 which was significantly different from all the varieties tested. Clones, Kp–90134.2 and CIP–386423.13 gave a non-significant yield difference. Unpaired t-test revealed that there was a significant difference between the two participatory research approaches, FFS and FRG, in respect to total yield. A higher yield advantage was obtained by using FFS approach when compared to FRG approach. On the other hand, when comparing the yield values obtained in sprayed and unsprayed plots separately, the clone CIP-392650.516 in sprayed condition gave the highest significant yield (P<0.05) under sprayed and unsprayed conditions. In general, the FFS approach helped the farmers' to acquire more knowledge and equipped them with technical know-how on the proper management of the potato fields which was reflected by the superior yield of the varieties. Keywords: Farmer field school, Farmer research group, Potato IDM, Late blight, AUDPC and Participatory researc
Effect of Fertilizer Sources on Potato Yield and Yield Components under Acidic Soil Condition in Central High Lands of Ethiopia
Get PDFAgronomic practices like fertilizer application and low soil pH which associated with soil infertility problems are considered to be among the major challenges to potato production in the highlands of Ethiopia. In response to this, an experiment was conducted to compare effect of different sources of fertilizes on potato yield and yield components from 2015-2016 main cropping season(June–August) in four districts of west and south west part of Ethiopia comprising two potato varieties Belete and Gudenie as main plot and five fertilizer source treatments as sub plot. These fertilizer source treatments were control, recommended Urea (165 kg/ha) and DAP (195 kg/ha), recommended Urea (165 kg/ha) and DAP (195 kg/ha) plus 225 kg/ha potassium sulfate (K2SO4), recommended Urea (165 kg/ha) and DAP (195 kg/ha) plus 225 kg/ha potassium chloride (KCl) and 242 kg/ha blended mineral fertilizer NPSB with N=18.9%, P=37.7%, S=6.95%, B=0.1% content plus 141 kg/ha urea under both limed and unlimmed soil conditions. The design was split plot with three replications. The data were analyzed using SAS soft ware versions 9.2. The experiment results showed that interaction of location and fertilizer types was highly significant in affecting total tuber and marketable tuber weight in t/ha. The Blended NPSB fertilizer was found superior in Welmera and Gumer location producing maximum total tuber yield of 33.21t/ha and 22.93t/ha respectively, under unlimmed soil condition while recommended urea and DAP provided maximum total tuber yield 31.38t/ha and 24.06t/ha under limed soil condition, respectively. In Jeldu growing location, the recommended urea and DAP plus KCl was produced maximum total tuber yield (19.13 t/ha under Unlimmed; and 23.9 t/ha total tuber yield under limed soil condition). In wenchi, the recommended urea and DAP was produced maximum 25.66 and 30.99 t/ha total tuber yield under both un-limed and limed soil condition, respectively. Interaction of growing year and location was highly significant in influencing average tuber number (total tuber number/plant) and average tuber weight (total tuber weight/tuber number). Interaction of location and growing year was highly significant in influencing dry matter under un-limed and limed soil condition. From these results, it can be concluded that the growing location and fertilizer sources had significantly affected the yield and yield component of potato both under limed and unlimmed soil conditions. Keywords: Potato, Potassium Fertilizer, Acid Soils, Lime Application DOI: 10.7176/JNSR/9-23-02 Publication date: December 31st 201
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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