A new instrument for the measurement of soil moisture suction

Current methods of determining soil moisture suction are outlined and their shortcomings identified. A new instrument is then described which will overcome a number of these problems by the use of a miniature pressure transducer, and minimum volume of water between the active face of the transducer and the porous stone. The instrument uses an Entran EPX-500 stainless steel miniature pore water pressure transducer, with a working range up to 3500 kPa, shrouded by a stainless steel sheath fitted with a porous stone. The mechanics of the instrument and its evaluation against known values of suction are outlined. Reliable measurements of suction were achieved up to 1500 kPa.