Soil salinization assessment on Iraq using satellite remote sensing imagery

Soil salinization is a form of topsoil degradation due to the formation of soluble salts at deleterious levels. This phenomenon can seriously compromise vegetation health and agricultural productivity, and represents a worldwide environmental problem. Remote sensing is a very useful tool for soil salinization monitoring and assessment. In this work we show some results of a study aimed to define the most suitable remote sensing methodologies for soil salinity assessment in Iraq. This activity is part of the Strategies for Water and Land Resources in Iraq project. The satellite images used were acquired by the ETM+ and by the SPOT5 satellite sensors, in the Visible-Near Infrared electromagnetic region, and with spatial resolution of 30 m (ETM+) and of 10 m (SPOT5). The methods used for the investigation of bare soils and vegetation can be summarized in: pre-elaborations (atmospheric corrections, georeferentiation, reflectance computation); individuation of bare soils and of vegetated soils; analysis of the correlations between several surface quantities computed from the satellite images and soil salinity indicators; analysis of the suitability of these quantities for soil salinity classification of the images using for example class separability analysis, principal component analysis and vegetation indexes. The first results obtained indicate that some areas with soil salinization, in particular those with outcrop of salt at the surface, and different type of vegetation can be individuated. The work carried out until now shows that remote sensing images could be fruitfully used for the soil salinization characterization of the studied area, but the definition of the methodology would require a dataset of ground information that describes in detail the actual soil salinization.