Keywords: Infrared spectroscopy; clay mineral; discriminant analysis

Abstract

Five soil sites were selected in the Middle Euphrates region, represented by the governorates (Diwaniyah, Najaf, Babel, and Muthanna), for soils of different agricultural exploitation (rice, vegetables, wheat, and palm trees), in addition to an unexploited agricultural soil. The soils were distinguished by having the same topography and climatic conditions and similar texture in order to study the weathering of mica minerals by using the infrared technique. The appearance of the absorption spectrum at the frequency of 3550 cm-1, with medium broadening in the unexploited agriculture soil (Muthanna), indicated a gradual transformation of mica towards di-octahedra minerals, and reflected the increasing substitution of Al+3 in tetrahedral sheet in these soils. The results of the examination of clay particles in soils exploited for cultivation of rice (Diwaniyah) showed that the absorption spectrum at the wavelength of 1642 cm-1 represents the absorption of zeolite water, while the presence of absorption spectra at the frequencies of 796, 1036, 3418, and 3616 cm-1 indicated the presence of mica minerals in all rice soils, also the presence of the broad absorption spectrum band at the frequency of 3418 cm-1, which was accompanied by the presence of the spectrum band at the frequency of 1036 cm-1.