Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-25T08:36:44.905Z Has data issue: false hasContentIssue false

A Comparison of two Agar Media for Counting Soil Micro-Organisms

Published online by Cambridge University Press:  27 March 2009

H. L. Jensen
Affiliation:
Department of Bacteriology, Rothamsted Experimental Station, Harpenden, Herts

Extract

1. Eighty counts of soil bacteria and actinomycetes, made on mannite-asparagine agar and dextrose-casein agar, showed that the latter medium gave significantly higher numbers of bacteria in 76 per cent. of cases, and significantly higher numbers of actinomycetes in 60 per cent. of cases.

2. On mannite-asparagine agar the values of χ2 of the bacterial counts were as a whole in agreement with expectation. The counts of actinomycetes colonies on this medium showed a tendency to subnormal variation.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1931

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Fisher, R. A.Statistical Methods for Research Workers (1930), 3rd ed. Oliver and Boyd.Google Scholar
(2)Fisher, R. A., Thornton, H. G. and Mackenzie, W. A.On the accuracy of the plate method of estimating the density of bacterial populations (etc.). Ann. Appl. Biol. (1922), 9, 325; Rothamsted Memoirs, 11.CrossRefGoogle Scholar
(3)Rao, M. G. and Subramanyan, V. Studies on soil Actinomyces. Part III. Standardisation of a plate method of counting soil Actinomyces. J. Indian Inst. Sci. (1929), 12A, 253.Google Scholar
(4)Smith, N. R. and Worden, S.Plate counts of soil micro-organisms. J. Agric. Res. (1925), 31, 501.Google Scholar
(5)Thornton, H. G.On the development of a standardised agar medium for counting soil bacteria (etc.). Ann. Appl. Biol. (1922), 9, 241; Rothamsted Memoirs, 11.CrossRefGoogle Scholar
(6)Thornton, H. G. and Fisher, R. A.On the existence of daily changes in the bacterial numbers in American soils. Soil Sci. (1927), 23, 253; Rothamsted Memoirs, 13.CrossRefGoogle Scholar
(7)Waksman, S. A.Microbiological analysis of soil as an index of soil fertility. II. Methods of study of numbers of micro-organisms in the soil. Soil Sci. (1922), 14, 283.CrossRefGoogle Scholar
(8)Waksman, S. A.Microbiological analysis of soil as an index of soil fertility. III. Influence of fertilisation upon numbers of micro-organisms in the soil. Soil Sci. (1922), 14, 321.CrossRefGoogle Scholar