Impact of Soil Water Repellency on Hydrological and Erosion Processes; A Review

Soil water repellency was first reported in the first half of the 20th century for peat soils. Depending on the severity of water repellency, a water repellent soil will resist water penetration during seconds to hours or even days. This has detrimental effects on surface and subsurface flow processes such as increased runoff, erosion, and preferential flow. The present study was conducted with the aim of investigating the effects of Soil water repellency on hydrological and erosion processes in order to identify gaps in the existing investigations. Major survey gaps remained, including the dissociation of the symptoms of water repellency on soil erosion such as the existence of a soil crust and little knowledge of the temporal patterns of water repellency and their hydrological outcomes. Understanding the mechanisms of water repellency is relevant to the separation of different causal chains as well as the adjust runoff coefficients in different water repellency areas. Soil water repellency can be caused by a variety of compounds and processes and generally occurs after a period of drying weather. Under such conditions, the soil can change from a wettable to a water-repellent state when dried below its critical soil water content. Soil water repellency is found to occur in different soils worldwide, ranging from coarse to fine-textured. Water repellency in soils can result in losses of plant-available water, reduced agricultural crop production, and deterioration of turf quality on sports fields