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University of Khartoum (2017)

Assessment of Land Degradation in the Central Part of North Kordofan State, Sudan, Using Geoinformation Techniques

Adam, Babiker Fadl Elseed Elsiddig

Titre : Assessment of Land Degradation in the Central Part of North Kordofan State, Sudan, Using Geoinformation Techniques

Auteur : Adam, Babiker Fadl Elseed Elsiddig

Université de soutenance : University of Khartoum

Grade : Doctor of Philosophy (PhD) 2017

Résumé
The objective of this study is the assessment of land degradation in the Central Part of North Kordofan State through monitoring and mapping changes in vegetation cover and land uses in the years 1972, 1987, 2001, and 2014. The study relied on the interpretation and analysis of the Landsat images from Multispectral Scanner (MSS) of year 1972, Thematic Mapper (TM) of the year 1987, Enhanced Thematic Mapper Plus (ETM+) for the year 2001, and Operational Land Imager (OLI) Landsat 8 of the year 2014, in addition to the analysis of soil samples, questionnaire, and meteorological data for 1984 to 2014. Normalized Difference Vegetation Index (NDVI), Object Oriented Image Analysis (OOIA) and Normalized Differential Sand Dunes Index (NDSDI) were the main methods adopted in this study to assess the extent and degree of land degradation in the study area. The results revealed that the region had witnessed vegetation degradation. Within the first period (1972 to 1987) there was decrease (-18.87%) due to drought. Within the second period (1987 to 2014) there was an increase of (+24.7%) during 27 years due to increase in rainfall. Conversely, bare land area decreased by (-15.78%) in the same period. The produced land use maps showed changes in the major classes (Vegetation, Cultivated and Bare areas) where cultivated area showed increase in area coverage from 15% of the study area in1972 to 27.5 % in 2014 due to increase in rainfall and population in the study area. NDSDI map showed an increase in the quantity of sands and sand dunes that was equal to (2.2%) in the year 2014 due to wind erosion. Furthermore, the results of the soil properties analysis (physical and chemical) particularly texture analysis showed that most of the soil samples in the study area have low clay and high sand content which can lead to soil erosion by the wind. In addition, most of the soils of the study area are non-saline and non-sodic, except some parts of the study area which were saline soil. Interpretation of field observations and ancillary data confirmed the role of human impacts on the temporal change in both vegetation cover and soil especially, around the villages. The produced land degradation risk map showed that most of the study area is at high risk of degradation. The results indicated a trend of increase in annual rainfall amounts and rise in temperature during the last 30 years. The study concluded that large part of the study area was affected by land degradation due to climatic variability, human activities and mismanagement of the natural resources. Applications of Geoinformation techniques is recommended to facilitate monitoring, assessment and modeling of land degradation and to support setting future plans for land resources management.

Présentation

Page publiée le 20 novembre 2018