Paper Title
Fabric and Micro-morphological Characteristics Study of different Rainfall Intensities Impact on Soil

Rain can break down soil aggregates and lead to formation of structural crusts, which effect on seed germination and soil water infiltration. In this research work, the impact of different rain intensities on micromorphological characteristics was studied. Experiments for simulating rainfall-runoff were carried out in different rain intensities (20, 37 and 47 mm/hour) on five soil samples with different physical and chemical properties and after the exit of gravitational water, the undisturbed soil samples were prepared by Kubina boxes. Then the soil samples thin sections were provided and studied with polarized microscope. Micromorphological characteristics of upper and lower parts of the crust were studied under different rain intensities with Image Tool3. Results indicated the main changes in upper and lower parts of crusts by different rainfall intensities and down ward movement of particles caused clay accumulation in 1.5 to3cm of crusts. Also intensity of 47 mm/hours produced a strong suspension and a Hallo pedofuture formation around the sand particles and Tuff. The classification of each slide, in two upper and lower parts with 0-1.5cm and1.5-3cm thicknesses, implied the existence of structural and void shape changes in soil fabric. Quantitative comparison and classification of three Voids Ferret Diameter data (30micron, 30-100 micron and >100 micron) with image tool analysis (UTHSCSA Image tool soft-ware and Image J(1.34s) and statistical analysis of data variance with five replication in Factorial Split- Split plot design variance analysis of databy MSTAT-C software indicated that there were significant differences at 5% level between the effect of soil type, rainfall intensity and Ferret diameter data in upper and lower part of crusts. Keywords: Crust, Image analysis, Micromorphological characteristics, Rain intensity.