Division 1.6.1 Apparatus

Test containers made of chemically inert material are used. They should be of a suitable capacity in compliance with the procedure used for incubation of soils, i.e. incubation in bulk or as a series of individual soil samples (see section 1.7.1.2). Care should be taken both to minimise water loss and to allow gas exchange during the test (e.g. the test containers may be covered with perforated polyethylene foil). When volatile substances are tested, sealable and gas-tight containers should be used. These should be of a size such that approximately one quarter of their volume is filled with the soil sample.

Standard laboratory equipment including the following is used:

• agitation device: mechanical shaker or equivalent equipment;

• centrifuge (3000 g) or filtration device (using nitrate-free filter paper);

• instrument of adequate sensitivity and reproducibility for nitrate analysis.