Tensiometers for Measuring the Capillary Tension of Soil Water1

ex,,p, ressions, such as "so!! pull", "saugkraft des Bodens , and force de suction du sol , have been used in the literature to refer to the security with which water is held by soil. With the development of a clearer understanding of the physical relationships involved, this property of soil began to be associated with the condition of the soil moisture, thus leading to the use of such terms as capillary potential, capillary pressure, sudtion pressure, pressure deficiency, and tension or capillary tension. Referred to atmospheric pressure as the zero reference, the pressure in water in an unsaturated soil is negative and it will occasionally be desirable to use the term tension or capillary tension as a name for this negative pressure, a