This document specifies laboratory methods for determination of the soil water-retention characteristic.
This document applies only to measurements of the drying or desorption curve.
Four methods are described to cover the complete range of soil water pressures as follows:
a) method using sand, kaolin or ceramic suction tables for determination of matric pressures from 0 kPa to -50 kPa;
b) method using a porous plate and burette apparatus for determination of matric pressures from 0 kPa to -20 kPa;
c) method using a pressurized gas and a pressure plate extractor for determination of matric pressures from -5 kPa to -1 500 kPa;
d) method using a pressurized gas and pressure membrane cells for determination of matric pressures from -33 kPa to -1 500 kPa.
Guidelines are given to select the most suitable method in a particular case.