SOIL MICRO-POPULATION STUDIES IN CONTINUOUS FIELD EXPERIMENT WITH EXCLUSIVE FARM-YARD MANURING OR EXCLUSIVE MINERAL FERTILIZATION
Especially convenient conditions for such investigations are created by stationary experiments of many years, standing.
Research work on determination of fungi groups under various ecological conditions has been carried out for many years at the School of Agriculture in Grignon (France). Data obtained in those investigations by Montegut and Guillemat [7, 8, 14] showed that specific changes in the groups of fungi were influenced by various ecological factors. The main factors are: soil type, pH, moisture, temperature and organic matter content.
It was stated by a number of investigators that as humus content in soil grew, the quantity of rot-root fungi diminished. The explanation given by Schönhar  is that in soils with higher humus content fungi antagonists of rot-root fungi are more numerous.