This procedure is performed on botanical materials (plant and feed) and miscellaneous samples such as manure to determine the moisture content of the sample as submitted.
Moisture is evaporated from samples in a forced-air oven at 55-60°C and Partial Dry Matter is determined gravimetrically as the residue remaining after oven drying. Some moisture remains in the sample because drying at this temperature does not remove all water. Drying at higher temperatures (greater than 60°C) causes chemical changes in the sample that affect subsequent testing. The Dry Matter test should also be requested if the total moisture content of the sample following drying at 105°C is required.
Partial drying of certain samples such as manure may not be compatible with subsequent analysis for constituents that might be volatilized or chemically or biologically transformed during drying.
NFTA method 18.104.22.168, Partial Dry Matter Using Forced-air Drying Ovens.