What measure indicates how fast water can move downward in a specific soil?

Permeability is the measure that indicates how fast water can move downward in a specific soil. It describes the ability of soil to transmit water and air through its pores and is a critical factor in understanding soil drainage and water management. Soils with high permeability allow water to flow through them more quickly, while those with low permeability retain water for longer periods.

In contrast, absorption rate reflects how quickly water can be absorbed by the soil rather than how quickly it can move through it. Retention capacity denotes the soil’s ability to hold water, and porosity refers to the volume of pores or spaces in the soil that can contain air or water. While all these properties are related to how soil interacts with water, permeability specifically quantifies the rate of water movement through the soil profile.