Hostname: page-component-cc8bf7c57-5wl6q Total loading time: 0 Render date: 2024-12-11T22:57:59.661Z Has data issue: false hasContentIssue false
  • English
  • Français

Observations on soil protozoa

Published online by Cambridge University Press:  27 March 2009

D. Ward Cutler
D. Ward Cutler
Affiliation:
(Rothamsted Experimental Station, Harpenden.)
Get access Rights & Permissions [Opens in a new window]

Extract

1. It has been shown that the direct counting method for soil protozoa devised by Kopeloff and Coleman for use in liquid media gives results entirely comparable with those obtained by a dilution method.

2. The factors governing the relation between the protozoa and the soil particles are those of surface action, and the capacity of various substances, sand, soil and clay, for retaining these organisms is specific and constant.

3. Coarse sand is capable of withdrawing per gram approximately 145,000 amoebae and flagellates per c.c. from a suspension of any strength. Fine sand withdraws approximately 980,000 per c.c: soil and partially sterilised soil 1,650,000, ignited soil 1,500,000 and clay 2,450,000.

4. These figures are constant for given material and organisms and are independent of the concentration of the suspension, the time of action, or whether the suspension contains cysts or active forms of the amoebae and flagellates investigated. Also the action is the same when the experiment is performed with a suspension of living or dead organisms.

5. Experiments with the ciliate—Colpoda cucullus—show that coarse sand per gram retains 27,000 per c.c.; fine sand per gram 185,000 per c.c; soil and partially sterilised soil 280,000 per c.c; ignited soil 270,000 per c.c. and clay 450,000 per c.c.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 9 , Issue 4 , October 1919 , pp. 430 - 444
Copyright
Copyright © Cambridge University Press 1919

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.Martin, C. H. and Lewin, K. R., Journ. Agric. Science, 7, 1915.CrossRefGoogle Scholar
2.Goodey, T., Roy. Soc. Proc., 88, 1915.Google Scholar
3.Kopeloff, N., and Coleman, D. A., Soil Science, 3, 1917.CrossRefGoogle Scholar
4.Kopeloff, N., Lint, H. C., and Coleman, D. A., Cent. f. Bakt. Bd 45, 1916.Google Scholar
5.Russell, E. J. and Golding, J., Journ. Agric. Science, 5, 1912.Google Scholar
6.Russell, E. J., and Appleyard, A., Journ. Agric. Science, 7, 1915CrossRefGoogle Scholar