Paragraph 2 PRINCIPLE
2.1
Solid fertilisers: the preparation of a final sample received at the laboratory is a series of operations, usually sieving, grinding and mixing, carried out in such a way that:—
(a)
the smallest amount weighed out laid down by the methods of analysis is representative of the laboratory sample; and
(b)
the fineness of the fertiliser has not been changed by the preparation to the extent that its solubility in the various extraction reagents is appreciable affected.
2.2
Fluid fertilisers: the final sample is mixed by shaking to ensure that any insoluble matter, particularly crystalline material, is thoroughly dispersed before each test portion is taken.