How does heavy rainfall cause erosion on unprotected dryland croplands?

On unprotected dryland croplands, heavy rainfall acts as a primary driver of soil erosion through two main mechanisms: physical impact and surface runoff.12

When raindrops strike soil that lacks the protection of vegetation, the force of the impact breaks the bonds holding soil aggregates together. This process can catapult soil particles into the air, effectively dislodging them from the surface. Furthermore, the force of large raindrops can cause soil compaction, creating a crust that reduces the soil's ability to absorb water.123

Once the soil structure is compromised, the resulting surface runoff carries the loosened particles away. This can occur as sheet erosion, where a thin layer of soil is removed uniformly, or as rill and gully erosion, where water concentrates into channels that carve deeper into the land. In dryland environments, where vegetation is often sparse, this loss of topsoil is particularly damaging, as it reduces the land's biological productivity and exacerbates the process of desertification.13245