Chapter 19 

 SOIL FUNGI 



In studies of soil fertility much emphasis has been placed upon 

 mineral composition, and all too little attention has been given to 

 microbial composition of soils. Indeed Boussingault and Lew y 

 (1853) long ago showed that the nitrate content of soils, if left 

 fallow, increased, but the causal relation of biologic factors was 

 not recognized at that time, nor was it definitely established until 

 1877. Then Schloesing and Miintz (1877), in epoch-making 

 studies involving the purification of sewage, established the foun- 

 dations of nitrification and soil fertility, and their findings consti- 

 tute the basis for present-day knowledge of relationships between 

 biologic factors and soil fertility. An appreciation of these mat- 

 ters can best be gained from reading The Microorganisms of the 

 Soil [Russell et al. (1923)], Principles of Soil Microbiology 

 [Waksman (1927)], and Die microscopischen Boden-Pilze 

 [Niethammer (1937)]. 



A proper appraisal of the composition of soil must take into 

 account its content of microbes, including bacteria, protozoa, 

 blue-green algae, green algae, and fungi. It appears that Adametz 

 (1886) was the first to isolate fungi from the soil. No real interest 

 in the fungus flora of the soil was manifest, however, until nearly 

 20 years later, when Oudemans and Koning (1902) isolated and 

 described 45 species of soil fungi. Subsequent studies on this sub- 

 ject may be grouped into three essential types: (1) taxonomic, 

 those concerned with the kind and number of fungi in soils; (2) 

 biochemic, those dealing with the physiological activities of soil 

 fungi; and (3) epidemiologic, those dealing with soil-borne plant 

 and animal pathogens. 



TAXONOMIC STUDIES 



Methods. As might be anticipated, various techniques for iso- 

 lating and culturing soil fungi have been employed. Oudemans 



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