The Use of Infrared Technique in the Study of Mica Weathering in the Rhizosphere Soil and Bulk Soil Under Different Plant Covering.


Three soil sites are chosen in the holy governorate of Kerbala / Al-Husseiniya region, for three types of trees (Morus, palm, and Citrus aurantium). Soils are characterized by similar texture, parent material, topography, climatic conditions and equal rainfall, in order to study the effect of biochemical activities in rhizosphere on weathering of mica and compare it with Bulk soil, by using of infrared technology. Results of IR spectrum inspections for Bulk soil show that the absorption spectra at wave length 1500-1650 cm-1 representing a zeolite water, with varying degrees of widens, reflecting the variation in degrees of clay minerals hydrolysis in these soils. In general the rhizosphere clay of Morus trees show the widest range of this absorption spectra, followed by the rhizosphere clays of Palms and Citrus aurantium trees respectively. The results show a presence spectrum of 3000-3800 cm-1 representing the substitution of Al3+ for Si4+ in tetrahedra sheet of mica, and the increasing width of this spectrum reflect more substitution of Al3+ for Si4+. Results show that the lowest width of this spectrum is found in rhizosphere soil of Morus trees, reflecting a high proportion of smectite in this soil. The low abundance of 1500 - 1650 cm-1 spectrum in Bulk soil of all trees, indicates the low degree of hydrolysis of the clay minerals in these soils. Also, the result show that the narrow spectrum range 1000 - 1050 cm-1, is found in all Bulk soils, which confirms the decline of transformation process of mica towards the 2:1 minerals in these soils.