What occurs when rainfall or irrigation exceeds the absorption rate of soil?

When rainfall or irrigation exceeds the absorption rate of soil, runoff occurs. This phenomenon takes place when the soil becomes saturated and can no longer take in additional water, resulting in excess water flowing over the surface of the land. Runoff can transport water along with soil particles, fertilizers, and other contaminants into water bodies, which can lead to problems like water pollution and soil erosion.

Leaching, while similar, refers specifically to the process where water dissolves and carries away substances from the soil profile, often in deeper soil layers rather than on the surface. Evaporation is the process by which water is converted from liquid to vapor, and transpiration involves the release of water vapor from plants into the atmosphere. These processes are related to the water cycle but do not directly address what happens when water exceeds the soil's absorption capacity. Thus, runoff is the correct term that describes the occurrence when there is excess water that cannot be absorbed.