Assessment of Soil Salinity Risk on the Agricultural Area in Basrah Province, Iraq: Using Remote Sensing and GIS Techniques

This study presents an integrated study of expansion process of salinized land in Basrah Province, a typical salt-affected area in southern parts of Iraq, by using geo-information techniques. Satellite images (Landsat TM 1990) and thematic maps (ETM 2003) were used to provide comprehensive views of surface conditions such as vegetation cover and salinization detection. With ERDAS software, the normalized differential salinity index (NDSI) and salinity index (SI) were computed and then evaluated for soil degradation by salinization. ARC/INFO software was used along with field observation data (global positioning system) for analysis. During the past 13 years, the salinized land in study area increased by 6 579.1 km(2) and in 2003 covered 34.5% of the total area; in the meantime, vegetation cover has decreased by 4 595.9 km(2) and in 2003 covers only 24.1% of the study area. Environmental changes show that, between 1990 and 2003, 37.5% of vegetation cover and 45.9% of marshlands were transformed into salty meadow and wet salty crust, respectively. In addition, there was 16.6% of sand lands converted into dry puffy salty crust. Results using spatial analysis methods showed that 7 894.9 km(2) (41.4%) of land had no risk of environment degradation by soil salinity, 4 595.9 km(2) (24.1%) had slight risk, 4 042.8 km(2) (21.2%) had moderate risk, and 2 536.3 km(2) (13.3%) of the total land area was at a high risk of environment degradation by soil salinity. In conclusion, the study area was exposed to a high risk of soil salinity.