[Methodical studies on determination of the number of micro-organisms in Cuban soils].

In four Cuban soils (ferrallitic soil, non-calcareous and calcareous brown tropical soil, and fersiallitic sandy soil) the suitability was tested of 7 dispersion solutions and of 4 culture media for determining the total number of bacteria, fungi and actinomycetes. The results were as follows: (1) The dispersion solution and the culture medium most suitable for the most comprehensive determination of the number of microbes is dependent on the physical and chemical soil properties. (2) The optimum combination of dispersion solution and culture medium was found for the various soils as follows: -Na-pyrophosphate in the soil extract and concentrated agar bouillon, respectively, for ferrallitic soils, -Na-K-tartrate solution and concentrated soil extract, respectively, for non-calcareous brown tropical soils, -Na-pyrophosphate solution in water and concentrated bouillon or soil extract, respectively, for calcareous brown tropical soils, -soil extract as a dispersion solution and as culture medium in fersiallitic sandy soils.