Porosity is the ratio of the volume of all the pores in a material to the volume of the whole. Porosity or pore space refers to the volume of soil voids that can be filled by water and/or air.
Porosity is calculated as a percentage of the soil volume with inputs:
`V_p` - Volume of Pores
`V_"total"` - Total Volume of sample
Compaction, Porosity and Soil Temperature. http://www.swac.umn.edu/classes/soil2125/doc/s6chp3.htm [Retrieved Sept 23rd 2015]