What effect does clay have on soil erodibility?

Clay particles have a significant impact on soil erodibility due to their physical and chemical properties. These small particles are cohesive, which means they tend to stick together, forming aggregates that resist water and wind erosion. When clay is present in soil, it contributes to the soil's structure and stability, making it less susceptible to erosive forces.

Furthermore, the fine nature of clay allows for better water retention, which can mitigate surface runoff—the primary driver of erosion. The presence of clay can also enhance the soil's nutrient retention capabilities, creating a healthier environment that further stabilizes the soil.

In contrast, soils with high sand or silt content typically have greater erodibility because they lack the binding properties of clay, making them more vulnerable to erosion by wind and water. Thus, the correct answer highlights how clay's cohesive properties and influence on water retention and soil structure contribute to decreased soil erodibility.