Influence of Different Vegetation’s on Characteristics of Mollisols at North Western Iraq
Study area was located at Shiladezi complex, Duhok governorate,Kurdistan Region, Iraq. Climate was warm to temperate in summer, and cold rainy in winter. Topography of study area was undulating to mountainous and forest vegetation in the area was oak trees previously. Parent material of study soils was calcareous and seven pedons were dug depending on the topography and vegetation cover. Generally field description of study pedonsshowed contrasting in morphological properties and this belongs to the effect of landscape, land use, and microclimate through affecting on the intensity of pedogenic processes. The results emphasized, all study pedons were development and containing master horizons (A, B, and C) with exception pedon (5) consider un-development and including (A and C) master horizons. Morphological results about soil development proved by physical and chemical criteria (ClB/ClA and CaCO3B/CaCO3A) and both of them indicated to development of study soils in all pedons regardless pedon (5). Texture of the study soils were ranged between silty clay to loamy. Soil structure was crumb or granular at surface horizons as whereas in subsurface horizons was blocky or prismatic. The results showed dominance of dark color for most study soils and the dark red color of studied pedons belongs to the effect of parent materials and sesquoxides in study location. Implications explained differences in surface horizons thickness with difference in pedon position that reflects the effect of pedogenic processes particularly sedimentation process moreover; land use and topography affect the surface horizon thickness. There is a variation in some morphological properties and this is due to the effect of slope degree and the differences in vegetation cover. The dominance pedogenic processes in study soil are illuviation, eluviation, melanization, leucinization, lessivage, and humification. The study soils in all pedons with exception pedon (5) were classified as Mollisols, Xerolls, Haploxerolls, Typic Haploxerolls, whereas in pedon (5) soil was classified as Inceptisols, Xerepts, Haploxerepts, Humic Haploxerepts.It can be concluded that soils in study pedons were development and tend to be fine texture in addition soil structure in surface horizons was granular or crumb and in sub-surface horizons was angular or sub-angular blocky with dark color as well as dominance of mollic and argillic diagnostic horizons.
Keyword - Mollisols, Pedons, Soil Development, Soil Morphology, Soil Texture, Soil Structure, Horizons.