ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The influence of several environmental factors on microbial activity in soil was measured by CO2 evolution, substrate disappearance, formation of intermediates, and changes in pH. Although good correlation was obtained between these parameters, microbial activity was not directly correlated with the numbers of bacteria and fungi estimated by dilution plating. Possible explanations for this are presented. The results obtained indicated that the decomposition in soil of even a simple substrate, such as glucose, is complex. The kinetics of glucose decomposition appeared to be composed of a series of first-order reactions, presumably resulting from the rate-limiting influence of nitrogen, phophorus, other elements, and space for development, respectively. Although the concentration of inorganic nutrient elements limited the rate of glucose decomposition, it did not affect the extent of decomposition. The influence of each of the limiting factors was discussed. No inhibitors of microbial activity were detected in the soil after 69 days of incubation with glucose. Some inhibition was noted when high levels of glucose and minerals were added, presumably the result of hypertonic osmotic pressures and/or toxicity of glucose. The diffusion rate of liquids through the soil was rapid, but that of gases was not, and some anaerobic breakdown of glucose occurred. A limitation of available space for development of sequential microbial populations was inferred, and the implications of this as an ecological factor were discussed. The results of this study indicated that the techniques of the pureculture microbiologist can successfully be applied to soils, and that factors which limit microbial activity in pure culture are also operative in soil.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00422050
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