Impact of land form Position and Soil Properties on Soil pore Distribution in Hilly Regions of Koohrang

According to importance of soil moisture for vegetation cover and plant growth in semiarid area such as central Iran especially under rain fed conditions. The knowledge about the soil porosity for supporting the available water is informative. Micro morphology as an applied science describes, interprets and measures the components, features and fabrics of soils The objective of this paper is to determine the most important soil properties on soil pores distributions in vertisols in hilly regions of west of Iran. The studied area was located in Koohrang district in Chaharmahal and Bakhtiari Province. The results of micro morphological studies revealed that there is a significant relationship between soil organic matter and total porosity. The total porosity was significantly correlated positively with the soil organic matter and negatively with the bulk density. Moreover, the total soil porosity was decreased within the soil depth in consistence with increasing bulk density and compactness. Also, the soil porosity was decreased along the hillslope from summit to toeslope induced by increasing bulk density. The results also showed that application of image analysis using Photoshop software provide valuable information for soil porosity and pore size classification. Our findings also showed that the soil physical and chemical properties are affected by slope position. The translocation of fine materials such as fine clay from upslope to downslope has led to accumulation of fine and expandable clays in down slope and consequently vertic properties have been generated in the studied area.