Soil Characteristics and Aggregate Stability
Yves Le Bissonnais
Abstract
In this chapter, the main soil properties affecting aggregate stability and erosion are reviewed. Then the relationship between aggregate breakdown and erosion is discussed. The main primary soil properties influencing aggregate stability and erosion have been relatively well known since the early works of Yoder, Henin and Ellison. In Africa, working with various sandy soils, Obi et al. found that runoff and erosion were best predicted by sand percentage with a negative relationship. Clay mineralogy influences erosion processes, but the effect is difficult to assess because soils most often contain a mixture of clay minerals. Organic matter is one of the most important and well-known aggregate stabilizing agents in soils. The nature and amount of exchangeable cations influence erosion through their effect on the clay dispersion/flocculation processes. In summary, there is good evidence for the positive effect of sesquioxides on aggregate stability for tropical and lateritic soils.