Bacterial Flora of the Soil

On the other hand, it has been found that these bacteria become less numerous as we go deeper into the soil, disappearing almost entirely at a depth of 3 to 4 meters  

These figures, however, are by no means absolute, since they are modified by the large number of organisms that live in the ground, such as insects, larvae, earth-worms, etc., as well as by the roots of plants, which, from the fact of their very deep penetration into the soil, favor the dissemination of bacteria, and at the same time influence the development of the latter by slightly changing the substrate throu their secretions. 

The importance of micro-organisms in the transformations taking place in the soil is evident from the following experiment of Miintz and Coudon, who have shown that if dried blood is added to a slightly calcareous earth, which is then sterilized at 120°, its inoculation with soil bacteria causes the appearance of considerable quantities of ammonia  

Different lots of earth. Initial content in NHs per zoo g. earth. Alter 70 days content in NH, per too g. earth. Ammonia formed per zoo g. earth. 

Inoculated with Mucor racemosus. Fusaritim MUntzii. 16.3 +3-5 27.2 

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