Impact of different soil-surface cover characteristics on runoff and soil erosion by water.

The effectiveness of soil-surface covers (e;g. geotextiles, rock fragments, mulches) in reducing runoff and soil erosion by water is often assessed only based on their cover percentage. However, some studies indicate that other characteristics, e;g. thickness, structure or vertical position of the surface covers in the soil toplayer, can also significantly influence their erosion-reducing effectiveness. Often rock fragments or mulches are partly embedded in the soil toplayer. Previous research indicates that the vertical position of rock fragments in the soil toplayer significantly affects hydrological and erosion processes (e.g. Poesen et al., 1990; Valentin en Casenave, 1992; de Figueiredo en Poesen, 1998). For rock fragments resting on top of the soil surface less runoff will be produced compared to the same percentage of rock fragments totally enmbedded in the soil surface. Therefore, a comparison of the erosion-reducing effectiveness of these rock fragments based only on cover percentage appears to be unsuitable. However, there is limited data available on the effects of these characteristics on the runoff and erosion-reducing effectiveness of surface covers. The objective of this postdoctoral research is to assess the influence of the vertical position of rock fragments in the soil toplayer on their erosion-reducing effectiveness using controlled laboratory experiments.

Keywords:Runoff, Infiltration, Interrill erosion, Rock fragments, Soil toplayer, Surface cover

Disciplines:Soil sciences, challenges and pollution, Agriculture, land and farm management