Assessing Relation of Soil Hydrophobicity and Soil Water Content and Determining Threshold Moisture of Organic Soil Samples

Soil water content is the most effective factor associated with the hydrophobic and hydrophilic changes in a soil. Water repellency in soils, is not a permanent feature; it can be reached in the dry season and reduced or eliminated in the wet season It can be said that in terms of moisture, there is a critical region that is defined as the threshold moisture content, where in lower moisture, the soil is repellent and in higher moisture, the soil is wet able. The purpose of this study was to investigate soil moisture variations on degree of hydrophobicity and determine the amount of threshold water content in soil samples of wetland around Shahr-e-Kord. In this study, some samples of Shahr- e-Kord wetland were investigated. After determining the initial moisture content of the soil, the soil hydrophobicity conditions were determined by determining the time of water droplet penetration (WDPT). Soil moisture variations were carried out using soil wetting and drying method, and in each step the soil hydrophobicity conditions were tested. Reducing water content in soil samples, led to a change in the degree of hydrophobicity in hydrophobic samples, in one soil hydrophilic soil sample, Reducing water content changed hydrophilic soil to hydrophobic soil. The threshold water content was also observed up to a maximum of 54% volumetric water content at a given point. Based on this, the higher moisture content of the threshold at this point indicates the higher soil potential for runoff generation. Soil analysis showed that soil organic matter had a positive correlation with threshold water content.