Browsing by Author "Negash, Legesse (PhD)"

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    Acaia Byssinica Hochst. Exbenth: Pod and Seed Characteristics, Germination Physiology and Potentials for Seedling Establishment on Degraded Land
    (Addis Ababa University, 1998-06) Haile, Berhank; Negash, Legesse (PhD)
    This study was conducted on pod and seed characteristics, gel1ninalion physiology as well as the potentials of Acacia abyssinica Hochst. ex Benlll ssp. abyssinica fOI' growing on degraded land. Mature pods of A. abyssinica were collected ji'01/l Irees found in alld around Addis Ababa (wilhin a radius of 35 km). One hundred pods pel' tree were collected ji'on, 26 diJ)erellt frees. Comparison of the lIIeans of pod lenglh, pod widlh and seed nUlllber per pod showed Significant dij)erences (p < 0.05) among samples obtained ji'om the dij)erent localities. Pod lenglh, pod width and number of seeds per pod ranged between 3.7 and 14.4 cm, 1.0 and 2.7 CIII and 2 and 13 respeclively. 11lere was no significant correlation benveen pod lenglh and widlh. Pod lenglh and number of seeds per pod were significanlly correlated (p ~ O. OOO). On the other hand, pod widlh and number of seeds pel' pod were negalively cOI1'elaled (p ~ 0.000). Seeds collecled ji'om 35 dij)erent h'ees were made into 17 bulks (each containing 1000 seeds). 111e weight oflhe bulks ranged ji'om 74.01 to 116.11 g. There were significant dij)erences (p ~ O. OOO) among Ihe mean weights of the 17 seed bulks. E.Dects of gibberrelic acid (GA;I, indole-3-aceclic acid (lAA) and kinetin wilh concenh'alions ranging ji'01n 1IJ' M to 11J7 JIIi on percentage gennination and radicle length of chemically scarified seeds ofA. abyssinica were exall/ined None of Ihe plant growth regulators significantly increased Ihe total percenlage gel1l1ination of seeds as compared to the control. Gennination percentage decreased Significantly at higher concenh'ations of fAA (IIJ' ,vi and 10-' Ai) and kinetin (I (f' ill!). 1AA at 11J' }.i delayed genllination for aboul a week as compared to the other concenh'alions of the same, Ihough 63% of the seeds genllinated wilhin 10-15 days after incubalioll. GA, (at 11J' ill!) Significantly increased radicle length, while 1AA at 10-' 1'v1, 1IJ'M and 11J7 ivi significantly decreased the radicle length as call/pared 10 the confrol. The investigation on the potential of Ihe species for growing on degraded land involved the growing of seedlings (GA, 10-' }v1 h'eated and Ihe conh'ol) in plastic bags in Ihe greenhouse. Soil samples ji'Oln degraded land were collecled ji'om geomorphicolly different locations ji'om an area co 4 km' along Ihe road on Ihe l'vfodjo-Zeway road, at aboul 81 km soulh of Addis Ababa. Soil samples that served as a control were collected ji'01l/ places in and orollnd Addis Ababa where A. abyssinica is currently found growing. Gel1ninants ji'om 10-' JIIi GA, and the conh'ol were plan led in bolh types of soils and were left 10 grow in Ihe greenhouse fOI' 12 weeks. All the seedlings slllvived until ha/vest. Chemical and physical analyses of the soil samples were conducled in Ihe National Soils Laborato/y in Addis Ababa. The results of the analyses indicate that 10talnih'Ogen, organic carbon and available phosphorus were Significantly higher (p < O. 05) in the soils collecled ji'om places where A. abyssinica is cun'enlly grolVing than those ji'om Ihe deg/'Qded land On fhe other hand pH, No, K, Co, and CEC were found Significantly higher (p ~ 0.00) ill the soils collectedjimll degraded land The JIIeall vollies of plant height. IIIlmber ofbrallches. IIl1l1/ber of leaves. shoot dry weight alld root dry weight were fOlllld to be sigllificalltly higher ill the controls. FroJII the resllits. it cOllld be cOllelllded that: (I) the presellce of hard seed coats is the most ill/portallt factor inhibitillg gel7nillalioll ill seeds of A. abyssillica; (2) provided that seeds are carejilily scarified (chemically or mechanically), no gennination stimulators are required for obtaining maximum percentage germination; and (3) the slllvival (IIntii hmvesl) of the seedlillgs ill soils collected ji'om degraded lalld cOllld illdicate that A. abyssillica has the potelllials for growillg ill degraded land provided that the minimllm moistllre reqllirements of the species is met.
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    Growth Performance of two Evergreens and Three Deciduous Indigenous Trees of Ethiopia on Degraded Land at Tulu Korma
    (Addis Ababa University, 2007-06) Belude, Tamene; Negash, Legesse (PhD)
    A study was conducted on young trees of Prunus africana (Hook. f.) Kalkman, Podocarpus falcatus (Thunb.) Mirb., Millettia ferruginea (Hochst.) Baker, Cordia africana Lam., and Croton macrostachyus Del., planted and maintained within the land holdings of the Center for Indigenous Trees Propagation and Biodiversity Development. The Center is located at 47 Km west of Addis Ababa, along the highway to Ambo. From a mixed stand of young trees planted 5 months before the start of this study, 200 seedlings of P. africana, 185 seedlings of each of P. falcatus, C. africana, and M. ferruginea, and 110 plants of C. macrostachyus were randomly selected and tagged with labeled metal tags. These were followed up for 8 months from October 2005 to May 2006 by assessing parameters such as height, diameter growth, survival, relative growth rate, tip dieback and damage by browsers. During the study period, care and management activities such as watering at intervals of 3 days during the dry months, weeding, hoeing the seedlings, mulching, dung application, fencing and guarding were carried out. Guarding was done regularly, but other activities were done when necessary. Data on plant height were collected every 45 days; root collar diameter measurements were done at the end of the experiment; extent of survival and mortality and damage by browsers were inspected every month. Relative growth rates were calculated for the plant height taking the period of time between two successive measurements. Data were subjected to One Way Analysis of Variance (ANOVA) and Tukey’s Honest Significant Difference Test at P = 0.05. Growth performances of all species varied significantly regardless of the similar treatments administered. Consequently, for variables such as height, survival, relative growth rate in plant height, and tip dieback M. ferruginea performed better compared to all the other species; C. africana was good in root collar diameter increase, but ca 31.4% experienced dieback at the tip. Prunus africana was good in height increment, but ca 14.5% of the seedlings was damaged by browsing animals. C. macrostachyus was good in relative growth rate of seedling height, but 6.4% of the stock was damaged by tip dieback. Podocarpus falcatus was lowest in all the parameters measured, but was very good in terms of percentage survival. Overall, seedlings survival of the studied species wassignificantly higher during the period of rainfall and months of well-watering than during the dry and months less-watering. Soil analysis of the study site yielded a value of 1.3 ppm for available P, 0.071% of total N, and 1.6% of organic C. The values for available P and total N were below the standard minimum values, while that for organic C was somewhat marginal, thus warranting the classification of the site as degraded.
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    Methods for Clonal Propagation of Podocarpus Falcatus (Thunb.) Mire.
    (Addis Ababa University, 1993-06) Semagn, Kassa; Negash, Legesse (PhD)