Microsampling of rhizosphere soil and laboratory artifacts

A parallel analysis of the macrosamples of surrounding soil and microsample s of rhizosphere soil did not reveal the so-called rhizospheric effect. The data obtained showed that dilution significantly influences the results of determination of the number of soil microorganisms. The actual number of m icroorganisms revealed in soil samples greatly differed from the theoretica lly predicted values. The enumeration of microorganisms in soil microsample s by direct count and, especially, by the plating method with the use of co nversion coefficients based on the degree of sample dilution gave erroneous results.