What is soil erosion?

How rainfall causes soil erosion

Although it may seem harmless, the impact of a raindrop falling onto bare soil can be surprisingly powerful. When thousands of raindrops strike the ground during a storm, they break apart soil aggregates and dislodge individual soil particles.

As rainfall continues, water begins to flow across the soil surface (Movie 1). This moving water transports the detached particles downhill, gradually removing fertile topsoil and reshaping the landscape. Depending on the amount of water, the slope, and the condition of the soil, this process can range from a thin sheet of water washing away soil evenly to the formation of small channels and deep gullies.

In summary, water erosion occurs when rainfall detaches soil particles and surface runoff transports them to new locations. Together, rainsplash and overland flow are responsible for much of the soil erosion observed in agricultural and natural landscapes around the world.

Watch how a rainstorm event can lead to intensive soil erosion in this video created by Jannes Stolte, NIBIO.