Erodibility Indices Compared to Measured Values of Selected Trinidad Soils

Abstract

Abstract The most suitable erodibility index for tropical soils has not been determined. This study was therefore carried out with 10 selected Trinidad soils to compare three erodibility indices previously used with soils in different parts of the world. The erodibility of the soils was determined by the USDA Erodibility Nomograph, the Australian Erodibility Index, and the Modified Raindrop Technique and their suitability evaluated by comparison with the erodibility measured directly on four of the 10 soil types in the field. The USDA Erodibility Nomograph correctly predicted the erodibility class of the four soil types; the Australian Index in two of the four soil types; and the Raindrop Technique did not prove to be a suitable method. The number of drops required to break the soil aggregate in the Raindrop Technique depended on the wetting and drying history of aggregate. The erodibility of the four soil types determined by the Nomograph were all classified as slight.