1. This method is applicable to all fertilisers where a correction for moisture is necessary.
2. The sample is dried to constant weight in an oven at 100°C. The loss in weight corresponds to the moisture content of the sample.
3.—3.1 Suitable containers with lids ensuring air tight closure; the dimensions should allow the sample to be spread at about 0.3 g per cm2.
3.2 Electrically heated oven, suitably ventilated and capable of being maintained at 100±2°C.
4. See Method 1.
5. Weigh to the nearest 0.001 g, 5 g of the prepared sample and transfer to a previously weighed container (3.1). Place the uncovered container and the lid in the oven (3.2) for 2 to 3 hours. Replace the lid on the container, remove from the oven and allow to cool in a desiccator and weigh. Reheat for another hour, cool and reweigh. If the difference in weight exceeds 0.01g continue the heating and cooling procedure until a weight constant within 0.01 g is attained.
6. Calculate the total loss of weights and express it as a percentage of the original weight.