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. Porosity is a measure of the volume of air and water-filled pores in the soil. The STATSGO database does not contain a direct measure of soil pore space. However, a value for porosity can be calculated from the bulk density (BD) and particle density (PD), the ratio of the mass of all solid particles to the volume of the solids.

4/19/99