Moisture content of soil in % of dry weight.
The volumetric soil moisture content or simply soil moisture content is defined as the volume of water that can be removed from a volume of soil by drying the soil at 105°C. It may be expressed as a percentage or a fraction. The porosity of the soil (the relative volume of pores in a soil sample) represents the maximum soil moisture content.
Water content can be tested according ASTM D 2216-92 by determining the mass of the wet soil specimen and then drying the soil in an oven 12 - 16 hours at a temperature of 110°C. Values can vary from essentially 0% (near surface rubble, gravel or clean sand) up to 1200% (organic soil like fibrous peat).