Land degradation is a phenomenon that undermines the sustainability of natural resources so important to the lives of people, especially in rural areas.
Although degradation factors are known, its magnitude remains difficult to determine. Yet, to allow taking preventive measures, restoration or appropriate protection and implementation, knowledge of the state of affairs in terms of assessment, evaluation of resource degradation, its extent and severity, is lacking.
One of the major constraints to assess land degradation is the lack of efficient and harmonized procedures both at the national, regional and even international.
The dynamic around this issue should strike a chord with new aerospace technologies and related disciplines that help provide solutions in the assessment, control and fight against the degradation of natural resources.
Combined with Geographic Information Systems (GIS) and digital mapping, remote sensing provides technical solutions to identify and characterize the spatial entities and determine their temporal and spatial relationships. The methods used ensure opportunities for analysis and diagnosis of the vulnerability of natural resources.
Considering the results of some studies in the field of assessment of land degradation through the use of remote sensing, this paper is an effort to contribute to the development of evaluation of the state of land degradation methodologies. It proposes a systematic and integrated approach based on the combination of determination and radiometric indexes related to soil and vegetation to determine the evolution of the degradation, the degree of intensity and provide a cartographic base that underlines the phenomenon.
This approach helped to establish a general mapping of land degradation, study its dynamics in Kaolack, region located in the centre of Senegal and called Groundnut Basin, from 1996 to 2010 and proceed to the identification of priority areas where measures against degradation should be implemented.
Key words : natural resources, land degradation, evaluation, vulnerability, diachronic, remote sensing, GIS, image processing, radiometric index, thematic mapping.