USING A SCANNING ELECTRON MICROSCOPE IN DIAGNOSING OF CLAY MINERALS IN SOME IRAQI RICE SOILS

Abstract

The Middle Euphrates region, represented by the governorates of Diwaniyah and Al-Najaf, was chosen to conduct the current study. As the two governorates are famous for cultivating various varieties of rice crop. Two methods using to irrigated these soils during the growing season, and called locally wet and dry methods. The morphological features of clay minerals were studied using scanning electron microscope (SEM), to describe the changes that occurred to the mineralogical features of these minerals due to the influence of the irrigation patterns used during irrigation of these soils. The scanning electron microscope (SEM) results show that were many changes in morphological features occurs such as in size and shape of clay minerals, in particular to smectite minerals. The scanning electron microscope (SEM) figure of clays in Al-Najaf_(dry) soil showed some of particles appeared as well-formed imperfect hexagonal shape, which revealed that these particles belong to the chlorite mineral. While the mica minerals were appeared in lath-shaped, and rounded flakes in clays of all studied soils. Whereas the montmorillonite particles appear as a thin, webby crust, and have a flat, perming morphology.  The variation in the size of the montmorillonite particles was adopted as a basis for the occurrence of the Mg-hydroxide layer within the interlayers of montmorillonite.