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Legesse Negash 《Agroforestry Systems》2002,56(1):39-46
Erythrina brucei Schweinf. emend. Gillett (Papilionaceae),a tree species that is endemic to Ethiopia, is known to possess useful agroforestry attributes, but these attributes have not been quantified. To achieve this, propagation of the species, growth rate of young trees and their impact on barley (Hordeum vulgare L.), and leaf-nutrient concentrations were examined. Germination of seeds planted in plastic pots varied from 73 to 93%, and direct seeding in the field yielded 83%germination. Branch cuttings obtained from 2 to 3-year-old stock plants (n =150) resulted in 70 to 80% rooting within 8 to 12 weeks after setting cuttings into the rooting medium. Considerable nodulation occurred on leaves one year after planting out seedlings and stecklings. Leaf concentrations of Mg, N,P, and S were significantly lower in nodulated than in the non-nodulated leaves. On the other hand, leaf Fe concentration was higher in nodulated than in the non-nodulated leaves. There was no significant difference in Ca and K contentsbetween the nodulated and non-nodulated leaves. E. brucei-treatment significantly increased tiller and seed numbers, as well as seed weight. However, thousand-grain weight and grain size were similar in harvests from E. brucei-treated and the control plots. The results indicate that the species is easy to propagate by seed and vegetative means, grows fast, is desirable for intercropping, and has relatively high leaf-nutrient concentration.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Yoseph Legesse Yilkal Asfaw Mesfin Sahle Gelagay Ayelet Shiferaw Jenberie Haileleul Negussie 《Tropical animal health and production》2013,45(5):1265-1267
The study was conducted in three regional states of Ethiopia: Amhara, Oromia, and the Southern Nations Nationalities and people regional state from August 2007 to April 2008 with the objective of identifying the foot and mouth disease virus (FMDV) serotypes circulating in the region. Two serotypes were recorded from epithelial tissue and oesophageal–pharyngeal (OP) fluid that were taken from outbreaks in study regions of Ethiopia. Serotype O FMDV was identified in Girar Jarso, Yabello, and Ankesha Guagusa districts while SAT-1 was isolated in Surma and Maji districts from tissue samples and this was the first report of the FMDV serotype in Ethiopia. Similarly, the OP fluid samples were found positive for SAT-1 FMDV in Maji and Surma districts. 相似文献
3.
Relationship between hybrid performance and AFLP based genetic distance in highland maize inbred lines 总被引：1，自引：0，他引：1
B. W. Legesse A. A. Myburg K. V. Pixley S. Twumasi-Afriyie A. M. Botha 《Euphytica》2008,162(3):313-323
The objectives of this study were to determine the crossing performance of highland maize inbred lines for grain yield, days
to silk and plant height; estimate genetic distance (GD) among the inbred lines and in association with tester parents, and
to investigate the relationship of GD with hybrid performance and midparent heterosis (MPH). A total of 26 inbred lines were
crossed with six (population and line) testers in a factorial-mating scheme. The F1’s and the parents were evaluated at five locations in Ethiopia. Nine amplified fragment length polymorphism (AFLP) primer
pairs were used to genotype all the parents. The F1’s were found to vary widely for grain yield and other traits measured. Yield superiority of more than 30% over the best hybrid
check was obtained for some testcross hybrids. Midparent heterosis on average was moderate for grain yield and, plant height.
And for days to silking, MPH values were mostly negative. Mean GD values determined from the inbred lines by population tester
(0.680) and line tester (0.661) combinations were not significantly different. Cluster analysis separated the tester parents
from the corresponding inbred lines. AFLP grouping of the inbred lines was in agreement with their pedigree records. Genetic
distances derived from the inbred lines × all testers and from the population testers’ sub-group were not positively correlated
with hybrid performance and MPH for most traits. In contrast, correlations of GDs involving the line testers’ sub-group with
F1’s and MPH were significantly positive but with low magnitude to be of predictive value. 相似文献
4.
Legesse Getahun Siegmund-Schultze Marianna Abebe Girma Valle Zárate Anne 《Tropical animal health and production》2010,42(7):1531-1539
This study evaluates the household income contribution and the profitability of traditional small ruminant enterprises in
two mixed-farming systems of southern Ethiopia (viz. Adilo and Kofele). Small ruminant production is an integral part of mixed systems in the Ethiopian highlands. The assessment
of the current economic performance of small ruminants indicates production-related opportunities and constraints and provides
baseline data against which the success of future interventions can be measured. Detailed information on economic parameters
was gathered through a 1-year period of flock and household monitoring (155 households) between September 2005 and August
2006. Structured surveys were conducted with the participating households to elicit information on income-expense details
of small ruminant and other agricultural enterprises. Small ruminants contributed considerably to cash income and to a limited
extent to human nutrition especially when other sources were in short supply. The annual profit per animal ranged from 20
to 37 Ethiopian Birr. The return to capital was 17% in Kofele and 29% in Adilo, with both values vastly exceeding the national
interest rate. The sale of small ruminants contributed to 39% and 23% of total farm cash income among small ruminant keepers
in Adilo and Kofele, respectively. Sale prices are highest before holidays. Researches should target at how to use available
feed resources in a timely and cost-effective fashion to make use of the seasonal market opportunities. 相似文献
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Studies on the germination characteristics of various seed groups, extent of seedling and wildling establishment, as well as measurements on early seedling growth, were conducted on Prunus africana (Hook. f.) Kalkm. (syn. Pygeum africanum Hook. f.) (Rosaceae). Germination of seeds gathered en masse (together with soil and litter) from beneath Prunus trees was significantly greater (P < 0.01) compared to those collected in pure form from the ground (with or without fruit flesh) or those picked from the trees. Treating seeds with 10 or 100 µmol gibberellic acid (GA3) showed better germination than the control, but the difference was not statistically significant. Gibberellic acid at 1000 µmol (10–3 M) inhibited germination significantly (P = 0.02). Seedlings survived better in the glasshouse (90%) than in the nursery (87%). Whereas 60% of the 280 wildlings between 2.5 and 4.0 cm successfully established, only 10% of the 220 wildlings between 8.0 and 13.0 cm survived 3 mo after these had been maintained in the glasshouse. Seedlings derived from the GA3-treated seeds showed higher initial growth than the control owing to rapid hypocotyl elongation. Transferring seedlings to larger pots enhanced growth significantly after a lag period of about two weeks. Seedlings maintained in the glasshouse grew better than those in the nursery (P < 0.01). The study found that germination of seeds/fruits (gathered en masse from beneath trees) on a seedbed is convenient, technically less demanding, and is cost-effective. 相似文献
6.
地理信息系统(GIS)技术具有分析速度快、智能化、可视化和信息化的优点,利用 GIS技术研究农业面源污染问题已经成为近年来研究农业面源污染的一大趋势。本文阐述了基于 GIS在农业面源污染研究中的主要应用技术,包括农业面源数据处理与管理、时空分布与空间差异性、GIS信息系统开发、大数据可视化、模型模拟、污染风险评估及预警预测等,并提出了 GIS技术在农业面源污染控制和治理应用方面的发展趋势和研究方向。 相似文献
7.
A rapid vegetative propagation method is described for Olea europaea L. subsp. cuspidata [Wall. ex DC.) Ciffieri (syn. Olea
africana Mill.)]. Leafy branch cuttings were harvested from 6 to 7-month-old stecklings (= plants derived from rooted cuttings). Cuttings 2–3 mm in basal diameter were trimmed to 70–100 mm in length, with leaf areas reduced to 15–33 cm2. Indolebutyric acid (IBA) was applied at 0, 10, 20, 25, 30, 35 and 40 µg/cutting to each of the 70–80 replicate cuttings randomly allocated to each of the 7 treatments. Callusing and rooting occurred 3–5 and 5–7 weeks after treatment, respectively. The rooting success of cuttings treated with 20 or 40 µg IBA/cutting was 75 and 90%, respectively. Differences in rooting success, speed of rooting and root numbers between the control and the IBA treatments were significant (p < 0.01). Compared to seedlings of similar shoot height, rooted cuttings grew significantly (p < 0.01) faster and produced more biomass. It is concluded from this study that the rooting of leafy branch cuttings derived from young stockplants of wild olive is rapid, and that vegetative propagation is an effective means of regenerating this valuable, yet threatened, tree species. 相似文献
8.
【目的】 草原刈割利用是我国最常用的草原利用方式,刈割强烈影响草原生态系统呼吸（Re）和甲烷（CH4）的排放,但对草甸草原的影响大小及机制尚未定论。【方法】 文章利用静态箱-气相色谱连用,分析了刈割对呼伦贝尔羊草草甸草原Re和CH4排放的影响。【结果】 （1）与对照相比,刈割处理组2021年和2022年的Re（P<0.01）和CH4（P<0.05）通量显著降低,平均分别降低45.0%和1.2%;2021年刈割和对照处理的Re分别为（10.66±0.24）mg/（m2·h）和（6.05±0.16）mg/（m2·h）;2022年刈割和对照处理的Re分别为（11.52±0.38）mg/（m2·h）和（6.29±0.27）mg/（m2·h）;2021年刈割和对照处理的CH4排放量为（0.43±0.01）mg/（m2·h）和（0.40±0.01）mg/（m2·h）;2022年刈割和对照处理的CH4排放量为（0.43±0.01）mg/（m2·h）和（0.41±0.01）mg/（m2·h）。（2）刈割处理的土壤温度（P<0.05）和土壤湿度（P<0.01）显著增加。（3）函数拟合分析表明地上生物量与Re正相关,土壤湿度与CH4通量正相关。【结论】 呼伦贝尔羊草草甸草原中,刈割处理会显著降低生态系统呼吸和CH4通量,这对于了解和掌握刈割处理下羊草草甸草原温室气体排放特征及其影响机制,准确评估草原生态系统温室气体排放具有重要意义,为草原生态系统碳管理和可持续利用提供了重要依据。 相似文献
9.
Comparison of feed intake,body weight gain,enteric methane emission and relative abundance of rumen microbes in steers fed sainfoin and lucerne silages under western Canadian conditions 
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下载免费PDF全文 K. Bouchard K. M. Wittenberg G. Legesse E. Khafipour K. E. Buckley K. H. Ominski 《Grass and Forage Science》2015,70(1):116-129
Beef cattle are major contributors of enteric methane (CH4) emissions in Canada. Feeding forages containing condensed tannins (CT) has been suggested as a means of reducing enteric CH4 emissions and improving production efficiency. Sainfoin (Onobrychis viciifolia) is one of the CT‐containing legumes, which has also been recognized to have several additional beneficial properties. This study compared sainfoin silage (SS) and lucerne (Medicago sativa) silage (LS) with respect to animal performance, enteric CH4 production, abundance of selected rumen microbes and selected serum parameters in yearling steers during a Canadian winter. Sainfoin silage in our study contained approximately 12 g CT kg?1 dry matter (DM), a level which did not adversely affect silage palatability as steers fed SS experienced higher DM intake. However, animals fed LS and SS had similar body weight gain over the course of the trial. Feeding SS resulted in lower blood urea nitrogen concentrations and relative abundance of methanogenic archaea in rumen fluid. Yet, microbial population shifts fell short of exerting significant influence on enteric CH4 emissions. This study suggests that under western Canadian growing and animal‐rearing conditions, sainfoin is not yet competitive with lucerne forage with respect to enteric CH4 emissions or animal productivity warranting further research and development. 相似文献
10.
Surface (0–15 cm) and subsurface (30–45 cm) soil samples from under canopy, edge of canopy and away from canopy of isolated Cordia africana Lam. and Croton macrostachyus Del. trees and their leaves were examined to investigate leaf nutrient content, root biomass and the contribution of trees on farms to soil fertility parameters in Badessa area, eastern Ethiopia. Leaves of C. macrostachyus had 20% higher P and 25% lower K contents than those of C. africana. The studied species had comparable leaf N content. Both species produced shallow lateral roots that extended beyond the canopy zone. Typically, higher fine root biomass was observed in the surface soils than the subsurface soils. Both species did not affect soil organic C, pH and cation exchange capacity. Surface and subsurface soils under tree canopies had 22–26 and 12–17% higher N, respectively, than the corresponding soils away from tree canopies. Surface soil available P under tree canopies was 34–50% higher than the corresponding soil away from canopies. Available P content of subsurface soil was improved only under C. africana canopy. The available P of surface soil under C. macrostachyus canopy was more than double that for C. africana. Trees of both species increased underneath surface and subsurface exchangeable K by 18–46% compared with the corresponding controls. In conclusion, C. macrostachyus and C. africana trees on farms keep soil nutrient high via protection against leaching, translocation of nutrients from deeper to the surface layer and accumulation of litter, which create a temporary nutrient pool in the surface soils under their canopies. 相似文献
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