Influence of external factors on the composition of the soil microflora.

The changes in the soil microflora as a result of introducing various organic substances (gelatin, chitin, cellulose and beech sawdust) into the soil were studied. The work was supplemented by electron-microscopic observations. Substantial shifts in the quantitative composition of the microorganisms take place only in the case of compounds easily accessible to them. Certain substances induce changes in the ratio of the groups comprising the soil micropopulation.