Water Repellent Soils: A State-of-the-Art

摘要

Water repellency in soils has worldwide implications. In some cases, special management problems are created; but in other situations, the principles of water repellency have been used to humankind's advantage. Most problems arise because of poor infiltration, difficulties in establishing plants, increased runoff and erosion, and plant diseases. An especially acute problem in southern California is the relationship between these soils and the high rates of runoff and erosion on freshly burned watersheds. Water repellent substances have been beneficial in harvesting water and reducing evaporation losses. These same substances provide a practical method of improving soil structure and aggregate stability. Much is known about the physics of water movement through these soils and the role of fire in their formation. This knowledge has not been formulated into management guidelines, although some general recommendations are available. Large gaps exist, however, in understanding the long-term role this soil condition has in the dynamics of forest, brush, and grassland ecosystems. As our knowledge of this discipline expands, more intelligent management of this soil property will evolve in both wildland and cultivated ecosystems.