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1.
Eucalyptus spp. are among the most widely planted exotic trees in Ethiopia. Several damaging leaf pathogens are known from Eucalyptus spp. worldwide. Of these, Mycosphaerella spp. are among the most important, causing the disease known as Mycosphaerella leaf disease (MLD). Characteristic symptoms of MLD include leaf spot, premature defoliation, shoot and twig dieback. Recent disease surveys conducted in Ethiopian Eucalyptus plantations have revealed disease symptoms similar to those caused by Mycosphaerella spp. These symptoms were restricted to E. globulus trees growing in several localities in south, south western and western Ethiopia. The aim of this study was to identify the fungi associated with this disease. This was achieved by examining ascospore germination patterns, anamorph associations and sequence data from the Internal Transcribed Spacer (ITS) region of the rRNA operon, for representative isolates. Several different ascospore germination patterns were observed, suggesting that more than one species of Mycosphaerella is responsible for MLD on E. globulus in Ethiopia. Analysis of sequence data showed that three Mycosphaerella spp., M. marksii, M. nubilosa and M. parva were present. This is the first report of these three species from Ethiopia and represents a valuable basis on which to build further studies in the region. 相似文献
2.
A study was undertaken from October 2006 to March 2007 to determine the prevalence and antimicrobial resistance patterns of Salmonella serovars. Liver, mesenteric lymph nodes, intestinal content, and carcass swab samples (each n?=?186) were collected from 186 apparently healthy slaughtered cattle at Bahir Dar abattoir. Bacteriological analysis was done according to the International Organization for Standardization (ISO 6579 2002). Isolates were serotyped at Agence Française de Securite Sanitaire des Aliments, Cedex, France. Twenty-eight isolates consisting of Salmonella Typhimurium, Salmonella Newport, Salmonella Haifa, Salmonella Heidelberg, Salmonella Infantis, and Salmonella Mishmarhaemek were identified. Salmonella Typhimurium and Salmonella Newport were most frequently isolated while Salmonella Heidelberg and Salmonella Mishmarhaemek were isolated least. Eleven of the 28 (39.3%) were resistant to one or more of the antimicrobials tested. Resistance was shown to ampicillin, chloramphenicol, gentamycin, norfloxacin, polymyxin-B, streptomycin, tetracycline, and trimethoprim. Four of 11 (36.4%) were multiple antimicrobial resistant. All the isolates tested were susceptible to the antimicrobial effects of gentamycin, norfloxacin, and trimethoprim. Eleven, four, and two isolates of the 28 were resistant to streptomycin, tetracycline, and ampicillin, respectively. All isolates of Salmonella Infantis, Salmonella Typhimurium (except one), and Salmonella Mishmarhaemek were susceptible to the tested antimicrobials. One Typhimurium isolate was resistant to chloramphenicol, streptomycin, and tetracycline. Salmonella Haifa was multiply antimicrobial resistant to ampicillin, tetracycline, and streptomycin. All isolates of Salmonella Heidelberg were resistant to streptomycin. Results of this study indicated high level of carcass contamination with antimicrobial-resistant Salmonella serovars which could pose public health risk; suggests need for hygienic slaughtering operations and proper cooking of meat before consumption. Further detailed studies involving different abattoirs, animal products, food items, and animals on different settings were recommended in the study area. 相似文献
3.
Despite the wide distribution of natural stands of Acacia senegal in Ethiopia, commercial exploitation of gum arabic is constrained by lack of tapping and development techniques. We evaluated the gum arabic yield from natural stands of A. senegal and the growth of 6 provenances in different parts of the country. For the gum yield evaluation from natural stands, four tapping positions and three tapping seasons were tested in a factorial RCB design. The second experiment in Metema evaluated survival and growth of six provenances. A. senegal trees in natural stands respond well to tapping if tapped during the appropriate season and at the correct position on the tree. The mean gum yield did not vary significantly by tapping season (p=0.63). Higher mean yield was, however, collected from trees tapped in October (96 g·tree?1 per two harvests). The mean yield differed significantly (p=0.009) between the tapping positions. Mean separation (α=0.05) shows that trees tapped at mid stem gave higher yield (160 g·tree?1 per two harvests). The interaction effect of tapping season and position was not significant. Higher mean yield ((70 ± 112) g·tree?1) was recorded in mid October-mid stem in two harvests. The second experiment indicated statistically significant difference in mean survival (p=0.0298), height (p=0.000) and root collar diameter (RCD), (p=0.012) between the six provenances. Highest survival, height and root collar diameter growth was observed from Abderafi provenance (100%, (148±11) cm, (38±11) mm, respectively). We recommend October and mid-stem and branches as appropriate tapping season and position. We recommend planting of the Abderafi provenance for the study area due to its superior growth and survival. Our study contributes to the proper selection of provenances for plantation development and improved tapping technology for better production of gum arabic in the country. 相似文献
4.
Ntsikane Maine James Lowenberg-DeBoer Wilhelem Thomas Nell Zerihun Gudeta Alemu 《Precision Agriculture》2010,11(5):448-463
The response of maize (Zea mays) to banded variable-rate nitrogen (N) application over a period of 3 years (2002/3–2004/5) is analyzed. The experimental
design alternated variable-rate (VR) and single-rate (SR) applications of N. The yield monitor data were spatially autocorrelated
and therefore were analyzed with spatial regression methods. The baseline spatial regression model defined in this study showed
that the VR treatment, treatment by year and treatment by management zone were statistically significant. Sensitivity tests
were applied; the first showed that VR treatment had a yield advantage when soil depth was greater than the field average
of 174 cm. The second test showed that the VR N rates applied were close to those that would maximize profit. Partial budgeting
indicates that benefits from VR vary from year to year, but in this test VR was slightly more profitable than uniform rate
application. Economic sensitivity testing indicates that farm size and the price of maize are the key factors in the profitability
of VR N. 相似文献
5.
Alemu Degitu Tegegne Firew Mekuriaw Yeshambel 《Tropical animal health and production》2020,52(1):123-129
An experiment was carried out to comparatively evaluate the effect of effective microbe (EM)– and urea molasses (UM)–treated finger millet straw (EMTFMS and UMTFMS, respectively) on nutrient utilization and growth performance of Washera lambs. Twenty yearling intact male Washera lambs with an initial body weight of 21.13?±?1.77 kg (mean ± SE) were used for feeding and digestibility trial. These lambs were grouped into five blocks of four animals and randomly assigned to four dietary treatments. The four experimental feeds were untreated finger millet straw (control) + 150 g wheat bran (WB) (T1), untreated finger millet straw + 150 g WB + 150 g Noug seed cake (NSC) (T2), UMTFMS + 150 g WB + 150 g NSC (T3), and EMTFMS + 150 g WB + 150 g NSC (T4). The lambs were de-wormed and vaccinated against ecto- and endo-parasites. Data were analyzed using ANOVA procedure of SAS. Results showed that crude protein (CP) content of finger millet straw (FMS) was improved from 2.13 to 9.7% in UM treatment and 2.13 to 2.39% in EM treatments. Total DM, CP, and OM intake were higher in lambs assigned in UMTFMS (P?<?0.01) and EMTFMS (P?<?0.01) than the control groups and significantly highest (P?<?0.01) in UMTFMS. A non-significant (P?>?0.05) difference was observed between treatment technologies in all nutrient apparent digestibility and average daily weight gain. Therefore, it can be concluded that both treatments could serve as an alternative measure to improve nutritive value of finger millet straw, but due to environmental effect, EM treatment could be safe.
相似文献6.
A field experiment was conducted to assess the effect of the combined use of farmyard manure and inorganic fertilizer on the growth and yield of sorghum and on soil chemical properties in a semi-arid area in northeastern Ethiopia. Twelve treatments comprising factorial combinations of four levels of farmyard manure (0, 5, 10, and 15 t ha?1) and three levels of inorganic fertilizers (0%, 50%, and 100% of the recommended rate) were compared in a randomized complete block design with three replications over a period of six years. The results revealed significant improvements in the growth and yield of sorghum due to the main and interaction effects of farmyard manure and inorganic fertilizer application. The combined application of farmyard manure and inorganic fertilizers increased post-anthesis dry-matter production by 147%–390% and grain yield by 14%–36%. The main effects of farmyard manure and inorganic fertilizers increased stover yield by 8%–21% and 14%–21%, respectively. Farmyard manure application increased total nitrogen (N) uptake by 21%–36%, grain protein yield by 8%–11%, and grain protein concentration by 20%–29%. Application of farmyard manure along with 50% of the recommended inorganic fertilizer rate resulted in a grain yield equivalent to, or greater than that for 100% of the recommended inorganic fertilizer rate, thus effecting a 50% savings of inorganic N and phosphorus (P) fertilizer. Application of 5, 10, and 15 t farmyard manure ha?1along with 100% of the recommended fertilizer rate and 5, 10, and 15 t farmyard manure ha?1 along with 50% of the recommended fertilizer rate can be recommended for farmers who can and cannot afford to buy inorganic fertilizers, respectively. 相似文献
7.
Aklilu W Alemu Adam L Shreck Calvin W Booker Sean M McGinn Liana K D Pekrul Maik Kindermann Karen A Beauchemin 《Journal of animal science》2021,99(1)
The present study evaluated enteric CH4 production, dry matter (DM) intake (DMI), and rumen fermentation in feedlot cattle supplemented with increasing concentrations of 3-nitrooxypropanol (3-NOP). A total of 100 crossbred steers (body weight, 421 ± 11 kg) was randomly assigned to one of four treatments (n = 25/treatment): control (no 3-NOP) or low (100 mg/kg DM), medium (125 mg/kg DM), and high (150 mg/kg DM) doses of 3-NOP. The study was comprised of 28 d of adaptation followed by three 28-d periods, with CH4 measured for 7 d per period and cattle remaining on their respective diets throughout the 112-d study. Each treatment group was assigned to a pen, with the cattle and diets rotated among pens weekly to allow the animals to access the GreenFeed emission monitoring (GEM) system stationed in one of the pens for CH4 measurement. Measured concentration (mg/kg DM) of 3-NOP in the total diet consumed (basal diet + GEM pellet) was 85.6 for low, 107.6 for medium, and 124.5 for high doses of 3-NOP. There was a treatment × period interaction (P < 0.001) for DMI; compared with control, the DMI was less for the low and high doses in period 1, with no differences thereafter. Compared with control (10.78 g/kg DMI), CH4 yield (g/kg DMI) was decreased (P < 0.001) by 52%, 76%, and 63% for low, medium, and high doses of 3-NOP, respectively. A treatment × period effect (P = 0.048) for CH4 yield indicated that the low dose decreased in efficacy from 59% decrease in periods 1 and 2 to 37% decrease in period 3, while the efficacy of the medium and high doses remained consistent over time. Irrespective of dose, hydrogen emissions increased by 4.9-fold (P < 0.001), and acetate:propionate ratio in rumen fluid decreased (P = 0.045) with 3-NOP supplementation, confirming that other hydrogen-utilizing pathways become more important in the CH4-inhibited rumen. The study indicates that supplementation of corn-based finishing diets with 3-NOP using a medium dose is an effective CH4 mitigation strategy for commercial beef feedlots with a 76% decrease in CH4 yield. Further research is needed to determine the effects of 3-NOP dose on weight gain, feed conversion efficiency, and carcass characteristics of feedlot cattle at a commercial scale. 相似文献
8.
L. German Hussein Mansoor Getachew Alemu Waga Mazengia T. Amede A. Stroud 《Agricultural Systems》2007
This paper focuses on the conceptual evolution of watershed management within the context of an action research program operating in the highlands of eastern Africa, as informed by both theory and practice. Following a review of the watershed management literature, and brief program and methodological overviews, the paper explores in detail the concepts of “participation” and “integration” in watershed management. Conceptual and methodological dimensions of the terms are discussed in the context of a watershed implementation process, clarifying how “watershed issues” are defined by local users, how “stakeholders” are defined with respect to those issues, and how participation and integration may be operationalized in practice. Data are selectively chosen from different pilot sites to illustrate how concepts underlying watershed management have been refined, and methods improved. It is clear that “participation” in problem diagnosis and program implementation must move beyond community-level fora to socially-disaggregated processes and explicit management of trade-offs to diverse groups. Secondly, integration does not come about through implementation of parallel interventions, but rather through an explicit analysis of potential trade-offs and synergies of interventions to diverse system components, and strategies to define and reach systems-level goals. Each approach requires attention to ways to optimize returns to diverse social groups and system components while minimizing negative spin-offs. The paper concludes with a discussion of implications for agricultural research and development in the eastern African region. 相似文献
9.
Seed composition is influenced by irrigation regimes and cultivar differences in soybean 总被引：1，自引：0，他引：1
In the midsouth USA, soybean is produced either under irrigated or non-irrigated conditions. The objective of this experiment
was to show the utility of supplemental irrigation as an alternative to full-season and non-irrigation to achieve high yield
and high seed composition. The effects of irrigation and cultivar differences on soybean yield and seed composition were conducted.
Two cultivars (Dwight and Freedom) and three irrigation regimes (full-season irrigation, FS; reproductive stage/supplemental
irrigation, RI; and non-irrigation, NI) were used. Protein percentage was higher in Dwight under FS and RI than NI. In Freedom,
protein percentage was higher under NI than under FS and RI. Under NI, Freedom had higher protein percentage than Dwight,
especially in 2004, but lower oil in 2003 and 2004. Cultivars showed significant differences in fatty acids. Yield in Freedom
under FS and RI was not significantly different. Nitrogen fixation was substantially higher under NI conditions. The results
indicate that irrigation management and cultivar selection significantly affect seed composition and yield. Protein increase
in Freedom under non-irrigated conditions may benefit producers for high protein seed under dry-land conditions. Supplemental
irrigation at the reproductive stage may be a possible alternative for full season irrigation for the cultivar Freedom.
Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the US Department of Agriculture. 相似文献
10.
Rients E. Niks Skye van Heyzen Les J. Szabo Sisay K. Alemu 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(2):393-405
The pathogenicity and identity was studied of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elymus repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus). We focused on the analysis of the host susceptibility of cultivated barley (Hordeum vulgare) to both pathogen samples, in direct comparison with an isolate of P. striiformis f.sp. tritici (Pst) and P. striiformis f.sp. hordei (Psh). At the seedling stage 83 % of the barley accessions were susceptible to PcE. At the adult plant stage, cultivated barley was predominantly resistant to this crown rust sample. Morphology, pathogenicity on Hordeum and Bromus and ITS DNA sequence analysis determined that PcE represents a European specimen of P. coronata f.sp. hordei. Sample Psb was pathogenic on 47 % of the cultivated barley at the seedling stage. This is intermediate between the isolates Psh (90 %) and Pst (10 %). Psb and Psh were pathogenic to grasses representing several genera. The host range of the Pst isolate was more narrow. We conclude that Psb is unlikely to represent a genotype of Psh that happened to have colonized B. carinatus, and is likely a distinct form of P. striiformis. 相似文献