Comments N196

Japan, June 7, 2002

In Japan, Macfadyen method is usually used to sample mesofauna such as Collembola and Acarida, however, there are no standard principles or procedures in the method on extraction apparatus, extraction time and temperature and so on. We agree that these mesofauna are regarded as indicators of soil environment. We have one evaluation method proposed by Dr. Junichi Aoki for this purpose, however, it has not become Japanese standard yet. It is important to select the species as the right indicators. As the N196 states, the species should be roughly identified and its biomass should be evalated.

The descriptions in the proposal itself are approximately agreeable except for the following points.

(1) For standardization, the size of extraction apparatus (Macfadyen apparatus), its material, the position of heat (light) source, and so on should be clearly defined, i.e., by using figures or illustration.

(2) It is necessary to have a manual which precisely describes the extraction conditions in detail. The conditions are such as the size of heat source, the distance from the heat source, soil amount to be extracted, and etraction time.

(3) We recommend a core sampler of either metal container of 50mm x 50mm x 50mm, or metal cylindrical one of 2000 mm2 x 50mm. It should not be limited only to the sampler of 400mm length and 25mm radius described in the proposal.

(4) Formalin should not be used as an fixing agent of the extracted fauna, because it gives risk to the health of person who carries out the method.

(5) No matter which sampling method is chosen, the final document should include some standard on biomass and kinds of Collembola and Acarida in an standard soil at a typical place and climate.

(6) It does not seem to be practical to have 10 minites of extraction time.