Mekeberiaw, Afework (2009) Analysis and Mapping of Soil Salinity Levels in Metehara Sugarcane Estate Irrigation Farm Using Different Models. Masters thesis, Addis Ababa University.
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Abstract
This thesis deals with the analysis and mapping of soil salinity levels in Metehara sugarcane estate irrigation farm. An attempt was made to identify salt affected areas by visual interpretation using both true and false colour composite. From the supervised classification, 726 ha area was mapped as highly saline. However, the result obtained from NDSI was not only in area-wise, but also the level of salinity as highly saline, moderately and slightly saline, determined based on the reflectance value. Out of the total area, 6% was mapped as highly saline. A regression analysis between EC values of small areas confined only in Metehara Sugarcane estate and the corresponding reflectance value in the NDSI image offer a polynomial relation of order two. The empirical model that obtained from the regression analysis was used to derive a salinity map and estimate EC level. The spatial distribution of salt affected area derived from NDSI and model were of similar pattern but of different extent. In overlay salinity model, four classes have been identified with varying degree of salinity. The class of highly saline soils was found in the areas underlained by the lacustrine Sediments and shallow ground water level. It is evident that the areas highly vulnerable to salinization greatly related to the ground water level that normally occurred on the lacustrine sediment near to lake Beseka. The validation of the two models has been carried out by the existing EC values referenced to the same locations by making linear correlation. The correlation shows that overlay salinity model to be a better indicator of soil salinity than empirical model in the study area. Since empirical model detects only the salts on the surface of the soil and gives a poor idea about the conditions below surface, the overlay salinity model indicates the condition and existence of salt in the entire soil section between the surface and root zone. Then overlay analysis between salt affected areas and canal, drainage, water table and soil was made to assess the spatial distribution as well as the relationship with these features. It was revealed that the spatial distribution was not highly influenced by the features considered except water table.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | EC, NDSI, Soil salinity, Empirical Model, Overlay Salinity Model |
| Subjects: | Q Science > Q Science (General) Q Science > QE Geology T Technology > T Technology (General) |
| Divisions: | Africana |
| Depositing User: | Selom Ghislain |
| Date Deposited: | 26 Jun 2018 10:26 |
| Last Modified: | 26 Jun 2018 10:26 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/4532 |
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