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Also known as: Moisture pressure
The equivalent negative pressure in soil water. It is equal to the pressure applied to soil water to achieve hydraulic equilibrium, through a porous permeable wall or membrane, with a pool of water of the same composition. The pressures used and the corresponding percentages most commonly determined are as follows
- Fifteen-atmosphere percentage
- The percentage of water contained in a saturated soil subjected to an applied pressure of 15 atmospheres until it is in equilibrium.
- One-third-atmosphere percentage
- The percentage of water contained in a saturated soil subjected to an applied pressure of 1/3 atmospheres until it is in equilibrium.