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| 1 | Effects of soil and water conservation practices on soil physicochemical properties in Gumara watershed, Upper Blue Nile Basin, Ethiopia显示文摘Background:Soil erosion is among the foremost causes of declining soil resources in Ethiopia,which in turn affect agricultural productivity.To limit this problem,for the last two decades in Gumara watershed,soil and water conservation measures have been practiced through free labor community mass-mobilization.However,their effect on soil fertility has not been evaluated.This study investigated the impact of implemented soil and water conservation measures on fertility improvement in the Gumara watershed.Both composite and core soil samples were taken from upstream,midstream,and downstream adjacent conserved and non-conserved cultivated and grazing plots.Selected soil fertility indicators were analyzed using standard laboratory procedures.Results:Soil and water conservation practices have resulted in a statistically significantly higher mean values of total nitrogen,exchangeable Na+and Mg2+at p<0.01,and of soil organic carbon and organic matter at p<0.05 in the watershed.The clay content,soil reaction,cation exchange capacity,and exchangeable K+showed nonsignificant,but higher mean values in conserved plots.Furthermore,the effects of conservation practices on soil properties were found more effective in cultivated land uses as compared to that of grazing land uses.This is because conservation treatments had significant effects on organic carbon,total nitrogen,exchangeable Na+and Mg2+in cultivated land uses but only on exchangeable Na+in grazing land uses.The interaction effect of treatments and land uses did not reach a statistically significant result for any of the soil properties considered in this study.Conclusion:Conservation measures have important implications for improving soil fertility in the Gumara watershed.Therefore,proper guidance and follow-up,use of agro-forestry and grass strips,and maintenance are required for the watershed’s sustainability and good soil conditions. | Mengie Belayneh Teshome Yirgu Dereje Tsegaye | 2019 | Ecological Processes2019，8，1： | 3 |
| 2 | Helium isotopic variations in Ethiopian plume lavas: Nature of magmatic sources and limit on lower mantle contribution显示文摘 | YIRGU R P G | 1996 | Earth Planet Sci Lett1996，，： | 1 |
| 3 | Relationship between mafic and peralkaline silicic magmatism in continental rift settings: A petrological, geo- chemical and isotopic study of the Gedemsa volcano, central Ethiopian rift显示文摘 | I Peccerillo A Barberio M R Yirgu G Ayalew D Barbieri M Wu T W | 2003 | JPetrol2003，44，11： | 1 |
| 4 | Forctors associated with success of vaginal birth after one caesarean section(VBAC)at three teaching hospitals in Addis Ababa,Ethiopia:a case control study显示文摘 | Malede Birara Yirgu Gebrehiwot | 2013 | BMC Pregnancy and Childbirth2013，13，： | 1 |
| 5 | Relationships between mafic and peralkaline acid magmatism in continental rift settings:a petrological,geochemical and isotopic study of the Gedemsa volcano,central Ethiopian rift显示文摘 | Peccerillo A Barberio M R Yirgu G Ayalew D Barbieri M Wu T W | | 0，，： | 1 |
| 6 | Petrogenesis of silicic peralkaline rocks in the Ethiopian rift:Geochemical evidence and volcanological implications显示文摘 | Peccerillo A Donati C SantoA P Orlando A Yirgu G Ayalew D | | 0，，： | 1 |
| 7 | Evolution of the southern Red Sea rift: birth ofa magmatic margin 显示文摘 | Wolfenden E C Ebinger C Yirgu G etal | 2005 | Geol Soc Amer Bull2005，117，： | 1 |
| 8 | Osmium isotopes and Fe/Mn ratios in Ti-rich picritic basalts from the Ethiopian flood basalt province: No evidence for core contribution to the Afar plume 显示文摘 | Rogers N W Davies M K Parkinson I J Yirgu G | 2010 | Earth Planet Sci Lett2010，296，34： | 1 |
| 9 | Relationships between mafic and peralkaline Silicic magmatism in continental rift setting: a petrological,geochemical and isotopic study of the Gedemsa Volcano,central Ethiopian rift显示文摘 | Peccerillo A Barberio M R Yirgu G Ayalew D Barbieri M Wu T W | 2004 | Journal of Petrology2004，44，11： | 1 |
| 10 | Evolution of the northern Main Ethiopian Rift:Birth of a triple junction显示文摘 | Wolfenden E Ebinger C Yirgu G | 2004 | Earth and Planetary Science Letters2004，24，12： | 1 |
| 11 | Runoff and soil loss responses of cultivated land managed with graded soil bunds of different ages in the Upper Blue Nile basin,Ethiopia显示文摘Background:In view of a wide range of on-site and off-site impacts of soil erosion,different soil and water conservation measures have been implemented mainly over the last two decades in the Gumara watershed and Ethiopia at large.But their effects have not been sufficiently documented,and maintenance of structures received very little attention.This study investigated the effectiveness of graded soil bunds of zero and 11 years of age in reducing runoff and soil loss.Six hydrologically isolated experimental runoff plots(three treatments×two replicates)were prepared to observe rainfall,runoff,and sediment concentrations in the 2019 summer rainfall season(covering approximately 70%of the annual rainfall).Results:Newly constructed soil bunds reduced runoff by 34.94 and 25.56%compared to the old and non-treated counterparts,respectively.Similarly,59.6 and 48.3%soil loss reductions were observed.The amount of soil loss in non-treated plots was twice that from the new plots and even 1.6 times higher than that from the old-graded soil bund treatments.The rate of soil loss in the new-and old-graded soil bund-treated and non-treated plots was 23.5,45.6,and 58.1 t ha^(-1) year^(-1),respectively.However,the effectiveness of the old soil bunds was much lower(only^(-1)2.6 and−21.7%in runoff and soil loss,respectively)than its new equivalent.Graded soil bunds,in its new form,reduced runoff,runoff coefficient,and soil loss significantly(P<0.05).Regardless of the treatments,from the start of the rainy season to the end,runoff and runoff coefficient showed an increase,but sediment concentration decreased.Newly constructed soil bund is the most effective in reducing runoff and soil loss.Conclusion:Graded soil bunds reduced runoff and soil loss significantly,but the rate even in the treated plots was very high when compared to both the soil loss tolerance(1-6 t ha^(-1) year^(-1))and formation rate(10-14 t ha^(-1) year^(-1))estimated for the area.Hence,these structures need to be supported by other measures such as grass strips,agroforestry,and percolation ditches,for better results.Besides,regular maintenance by either removing sediments from bund furrows or increasing the bund height is recommended for sustained reduction of runoff and soil loss. | Mengie Belayneh Teshome Yirgu Dereje Tsegaye | 2020 | Ecological Processes2020，9，1： | 0 |
| 12 | Parasitic plant in natural Boswellia papyrifera stands at Humera, Northern Ethiopia显示文摘In Boswellia papyrifera(Del.) Hochst natural stands, we studied the association of parasitic plants with B. papyrifera trees from which frankincense was tapped and marketed for domestic and export markets. Data on the rate of infection of parasitic plants on B. papyrifera was collected in three transects located at separate locations around Baha kar, northern Ethiopia. Each transect had ten circular sample plots of 400 m2 and separated by 100 m. Species composition, DBH, height, crown diameter, number of main, secondary and tertiary branches and number of parasitic plants on individual trees were recorded. Sixteen tree species were recorded in the combined sample plots. The parasitic plant associated with B. papyrifera was identified as Tapinanthus globiferus. This parasite infected 38% of Boswellia trees in sample plots. The infection rate of the parasitic plant varied from 1 to 33 per Boswellia tree. The infection of T. globiferus on B. papyrifera was predominantly limited to tertiary small branchlets arising from secondary branches; parasitic plants were absent on thick main and secondary branches. In all plots, infectionof T. globiferus was exclusively limited to Boswellia trees. The influence of T. globiferus parasitism on growth of Boswellia trees and its influence on yield of incense production needs further investigation. Management of natural stands for frankincense production should include measures to reduce infection by T. globiferus. | Abraham Yirgu Alemu Gezahgne Habtemariam Kassa Minilik Tsega | 2014 | Journal of Forestry Research2014，25，4： | 0 |
| 13 | The Seismo-Volcanic Crisis on the Dabbahu Magmatic Segment,Afar Rift,Ethiopia显示文摘The Afar depression is located at the junction among Red sea,Gulf of Aden and the East African Rifts.Tectonic and magmatic activities in Northern Afar have localized to approximately 60 km long, seismically and volcanically active magmatic segments. In September 2005 a seismo-volcanic event of unprecedented scale and intensity took place along the Dabbahu magmatic segment.This activity | Yaregal Yenealem Gezahegn Yirgu | 2009 | 地学前缘2009，16，S1： | 0 |
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