A GIS for the characterization and mapping of saline soils in semi-arid areas, case of Oued mina watershed (North West Algeria)

Abstract

The objective of this work comes in the characterization and mapping of saline soils in the wadi Yellel watershed of (700 km²), the main tributary of the Wadi Mina, drains an area estimated 15 000 ha. It is composed mainly of marls tertiary hence the name “zone of marl. The semi-arid climate of the watershed of wadi Mina accentuates the phenomenon of salinization can be classified according to their origin; there are few data on saline areas prior to the execution of irrigation works, which shows common characteristics between the soil and irrigation water. The vegetation covers of only7.20%, which leads to early degradation. We adopted a methodology based on the use of Geographic Information System, the data were selected inventory of soils and vegetation in order to map and integrate them into a database data in order to enhance the information in the environmental sphere. The advantage of this method in of outlook, it is to track spatiotemporal for help characterize changes in terms of salinity and degradation of the physical environment. This will be followed by direct observation in field, laboratory analysis and by using the System Information (GIS). The results show that soils are often clay with a high clay content (36-50%) and salts, they are occupied either by agriculture or abandoned to be occupied by halophytic vegetation. The first results are made available to managers for their decisions and development proposals.