Key Stage 3 (KS3) Geography Practice Test

The term that describes the change in available water in soil due to saturation over time is soil moisture. Soil moisture refers to the amount of water held in the soil, which is essential for plant growth and the overall health of ecosystems. Over time, soil can become saturated with water, particularly after heavy rainfall, leading to a change in the levels of water available to plants.

In contrast, infiltration is the process through which water enters the soil from the atmosphere, typically after precipitation. Percolation refers specifically to the downward movement of water through soil layers, which affects groundwater levels, but it does not capture the overall change in water available in the soil. Groundwater refers to water stored underground in aquifers, which is different from the water present in the soil profile. Thus, soil moisture specifically addresses the water held in the soil due to saturation.