Soil water repellency: Origin, assessment and geomorphological consequences

The study of soil water repellency has received increasing attention by the scientific community in recent years since it has been found to be a much more widespread property than previously thought and significant impacts on soil hydrological processes and erosion have been identified. In addition to these, soil water repellency has many other important consequences for soil functioning, fertility and ecological processes. As a result, researchers focusing on soil water repellency include not only soil scientists, but also those from other disciplines, such as ecologists, physicists, geomorphologists and engineers. Because of its importance and the relative ease of its detection, its study is becoming increasingly recommended to be included as part of standard soil analyses and for soil conservation and restoration works.One of the major research topics in the study of water repellency is the prediction of its occurrence through its relationship with key soil properties such as texture, organic matter content and chemical characteristics, acidity, mineralogy of the clay fraction and microbiology. Relationships between soil water repellency, soil management, water content and temperature have also been a major focus. In this introduction to this special issue, we aim to summarize, evaluate and set in context some of the latest advances, new ideas and trends that are presented by the papers in this special issue and identify the remaining key gaps in the current research on soil water repellency.