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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/235

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dc.contributor.advisorDr. Fisseha Itannaen
dc.contributor.authorMeron, Nigussie-
dc.date.accessioned2007-11-13T16:12:38Z-
dc.date.available2007-11-13T16:12:38Z-
dc.date.copyright2007-
dc.date.issued2007-11-13T16:12:38Z-
dc.identifier.urihttp://hdl.handle.net/123456789/235-
dc.descriptionMsc thesis submitted to the University of Addis Ababa School of graduate studies in partial fulfillment of the requirements for the degree of Master of Science in Environmenten
dc.description.abstractThe objective of this study was to characterize salt affected soils based on their salt content & to assess growth responses of selected species and identify salt tolerant species; namely, Rhodes grass (Chloris gayana), Setaria sphacelata, Saltbush (Atriplex halimus) and Guinea grass (Panicum maximum). Soil samples were collected from three different sites of southwestern shore of Lake Ziway area. Samples were taken in replicate of 16 from each site and composited. Soil chemical analysis of the soluble salts, exchangeable salts, EC, texture, calcium carbonate, pH, organic carbon and total nitrogen were done at Addis Ababa University and National Soil Research Center. In addition, to select salt tolerant plant species experiment was conducted in a greenhouse involving the different soil types and the four different plant species as experimental treatments. The experimental design used was CRD (Complete Random Design). Throughout the experimental period, survival percentage and height of each plant species were recorded. Based on the laboratory analysis, salt problem was observed in all the soil samples collected from the study area. According to the standard guidelines, all tested soil samples fall under the category of saline-sodic soils based on their salt content. Even though they all belong to same category, the absolute salt content of each soil type was very different. The EC, SAR, ESP value for soils collected from the first site was 9.3 dS/m, 58.7 & 34.3%, for soils from the second site, which was 19.3 dS/m, 385.9 & 78.8%, and for soils from the third site was 8.1dS/m, 95.3 & 65.5% respectively. These differences in absolute salt content were reflected in the differential responses of the plant species grown on them. There was statistically significant difference in the mean survival percentage between different species on soil types collected from the same site (P<0.05). This shows that there is a marked difference in salt tolerance between the selected species. In addition, the mean survival percentage & height attained by each species showed statistically significant difference between different soils collected from the three sites (P < 0.05). From all the planted species the survival percentage and height of only two species, namely Atriplex halimus & Chloris gayana were recorded on soils collected from the first and third sites. However, the other two species, Setaria sphacelata, & Panicum maximum were not able to grow on all the soils collected from the three sites. The survival percentage and height attained by the two species on soils from the third site was very low. The result suggests that the presence of high salt problem in the study area and some soils of the area could support the growth of two species. From the two species, Chloris gayana can be selected as a high salt tolerance grass for the salt content found in soils from the first site by observing its survival percentage. However, the survival percentage of other tolerant species, Atriplex halimus decrease drastically through time on both soils from the first and third sites and the survival percentage of Chloris gayana were very low on soils from the third site. So that it is difficult to select Atriplex halimus as salt tolerant plant for soils from the first and third sites and similar other soils and Chloris gayana for soils from the third site and similar other soils. In combination with these salt tolerant plants, it is advisable to practice other reclamation measures especially in areas with high salt concentration. Because most of the soils of the area could not support even high salt tolerant species.en
dc.language.isoenen
dc.publisher.publisherAddis Ababa Universityen
dc.subjectSalt affected soilsen
dc.subjectSalt tolerant planten
dc.subjectSoil chemical analysisen
dc.subjectSurvivalen
dc.subjectPercentageen
dc.subjectHeight of speciesen
dc.titleCharacterization of salt affected soils in the central Rift Valley and assessing salt tolerance of different plants: A case study at the southwestern shore of Lake Ziwayen
dc.typeThesisen
Appears in:Thesis - Environmental Sciences

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