Distribution of Soil Iron Oxides along Catena at Two Different Locations, in Erbil Province, Northern Iraq

Two locations selected in Erbil province, Northern Iraq. Three pedons were dug in each location on catena and twenty-three soil samples were collected for determine physical and chemical propertie. Increasing iron oxide causes coating of clay particles and decreasing the specific surface area in turn decreasing the ability of soils for adsorbing cations on it surfaces that causes decrease of cations concentration and cation exchange capacity. Conversely, high percentage of iron oxides that is act as cementing agent of soil particles and changing their sizes expectedly, in this way increase sand particles more than silt and clay particles. Total free iron oxides irregularly distributed and vibrated between increasing and decreasing. Generally, total iron oxides percent was relatively increased towards down of catena and highly related with parent material, topography, climate and vegetation cover additionally, related with the following soil forming processes, leaching, weathering, erosion, eluviations and illuviation. Increase iron oxides in study soils indicated to, increase soil development. Results of active ratio indicated to, soil development was increased towards down slope of catena. The objectives of this paper are study the soil characteristics and development of the pedons on catena and study the pathway of iron oxides distribution in pedons on catena. (paper)