Pressure membrane apparatus is used to measure matric potential moisture content relations at potential values as low as

Pressure membrane apparatus is used to measure matric potential moisture content relations at potential values as low as 100 bar. Application of specific potential to set samples, their soil water contents are determined gravimetrically.
Saturated soil samples are placed on a semi-permeable cellophane membrane with microscopic pores. This membrane allows the passage of water from the sample but retains the air pressure applied to the upper surface of the membrane.