Soil may be considered a porous three phase system composed of air, water, and solids. The relative distribution of these three components is important to understanding the hydraulic properties of the soil. Bulk density is the ratio of the mass of soil to its total volume (solids and pores together). Bulk density as recorded in STATSGO is a total, or wet, bulk density which is a measure of the total mass of a moist soil per unit volume. Bulk density is often an input variable in pedotransfer functions used to obtain soil hydraulic properties.

4/19/99