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.