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Competency Area 2: Soil hydrology AEM

PO 9. Describe the water budget for a soil profile.

The water "budget" for a soil profile refers to the water additions, subtractions, and the amount of water stored or remaining in the soil. The hydrologic cycle component which adds water to the soil is Infiltration, and Evapotranspiration processes are components of water removal.

Within a particular volume of soil, such as the plant root zone, is the soil water, the amount of water that the soil volume can store. The available soil water holding capacity refers to the amount of water the soil can hold, that is considered available to plants for evapotranspiration purposes.

Any excess water which infiltrates, and which cannot be retained as the soil water becomes deep percolation, the water that moves downward through the soil profile below the root zone; or if the downward movement is restricted, it's subject to interflow, the horizontal movement of water out of the soil volume. The interflow and deep percolation components produce the seepage flow.