General Biology

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Browsing General Biology by Subject "Acacia Abyssinica"

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    Coffee Shade trees Current Status Phenology Management Practices and Threats in Kochere Woreda Gedeo Zone SNNPR Ethiopia
    (Addis Ababa University, 2021-09-07) Agmas, Ahmed; Negash, Legesse (Professor)
    This study was conducted in Kochere woreda,Gedeo Zone,SNNPR, Ethiopia. The aim of this study was to identify the most common and important shade tree species,current status, phenology and threats and to document farmer’s perspectives on the environmental and socio economic benefits of the shade trees on coffee production systems. The data were collected through structured and semi structured interview,questionnaire,and field observations. Data were analyzed using preference ranking following (Martin,1995),direct matrix ranking following (Cotton,1996) and appropriate percentage were used. Wherever descriptive statistics were also computed so as to summarize the essence of the data. Six most common coffee shade tree species were selected in the study area. Farmers preferred these shade tree species in their coffee plantation due to their shade providing and soil fertility improvement and also based on their multipurpose values. Coffees under shade increase the yield and size of coffee beans however under sun growing,cup quality and coffee bean size decrease. Agroforestry practice was takes place deliberately the production of woody and non woody crops in the same field of land. Removing of weed,inter cropping,protecting natural regeneration plants,looping of side branches as well as pollarding and debarking were constitute the major management practices. People highly exploited in the natural environment as the source of their lively hoods,it promote negative effects on plant distribution. Regarding to threats of coffee shade tree informants clearly put their worries about the future prospective of these shade trees under the existing dynamics .This research identifies that the rapid population growth in the study area as a potential threat to the sustainability of coffee shade tree.
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    The Symbiotic Effectiveness and Diversity of Root Nodule Bacteria of Some Acacia Spp. From Sodo Wereda, Guraghe Zone, Southern, Ethiopia.
    (Addis Ababa University, 2017-08-02) Tuffer Abule; Assefa Fassil (PhD)
    The genus Acacia has a large number of species that are adapted in wide range of habitats in both tropical and temperate regions throughout the world for most of them fix nitrogen with rhizobia. However, nitrogen fixation by different species is not necessarily effective that needs compatibility of the rhizobia and the host varieties under different ecological conditions. Therefore, this was designed to isolate, phenotypically and symbiotically characterize acacia rhizobia from Sodo Woreda, Guraghe Zone, and Southern, Ethiopia under laboratory and greenhouse conditions. Thus, ten rhizobial isolates were collected from nodules of three different acacia species; Acacia seyal, Acacia abyssinica and Acacia negrii. They all induced nodulation upon re-inoculation on their homologous host plants. All isolates were fast growing, tolerant to high concentration of 6% NaCl concentration and grew over a wider range of temperature up to 43. Most of the isolates of Acacia abyssinica and one isolate of Acacia negrii, were capable of utilizing a various types of carbohydrates as carbon source. The symbiotic effectiveness of the isolates on the sand culture showed significant variations in nodule number, nodule dry weight, shoot dry weight, shoot length compared to their respective N- fertilized and N-fertilized -control groups. The maximum number of nodule and shoot dry weight of the inoculated plant were recorded by Acacia negrii with isolate AURAneg31.The minimum number of nodule was recorded by Acacia abyssinica with isolate AURAaby24.The highest shoot dry weight was observed N-fertilized (positive control) plant by Acacia seyal. However, shoot dry weight of N-unfertilized (negative control) plants less than both inoculated and uninoculated plants. Isolates of Acacia negrii, were very effective; AURAneg31 showed the highest value 91% of symbiotic effectiveness whereas both Acacia abyssinica and Acacia seyal were showed effective. Generally isolates of A. negrii were more competitive than other two species.