This procedure is performed on soil samples that are either field-moist, or have been air-dried or oven-dried at 55-60°C and ground, to obtain the dry matter content on a mass basis. The method quantitatively determines the dry matter content based on the gravimetric loss of free water associated with heating to 105°C for a period of three hours for pre-dried samples and 16-24 hours for field-moist samples. The method does not remove molecularly bound water.
NOTE: Some minerals similar to gypsum lose water of crystallization at a temperature of 105°C. This method is not appropriate for soils samples with a high organic matter content (>10% (m/m)), for example peaty soils.
Sample amount requested: Pre-dried material – 30 g; Field-moist material – 50 g
Questions concerning limited sample size can be answered by the UC Davis Analytical Laboratory.
ISO 11465:1993 Soil quality – Determination of dry matter and water content on a mass basis – Gravimetric method
