What does porosity in soil measure?

Porosity in soil measures the volumetric fraction of voids in the soil. Specifically, it quantifies the ratio of the volume of all the empty spaces (voids) in the soil to the total volume of the soil (which includes both the solids and the voids). This measurement is crucial in various engineering and environmental applications, as it directly influences water retention, soil aeration, and how well the soil can support structures.

Understanding porosity helps engineers predict how soil will behave under different conditions, such as drainage or loading. High porosity typically indicates that the soil can hold more water, making it important for agricultural and environmental considerations, while low porosity suggests denser soil that may compact more under load. The other options relate to different properties of soil that do not specifically measure the voids, but rather aspects like density, mass, or moisture content.