A COMPARISON OF MICROBIAL ACTIVITY IN AN ONTARIO FOREST SOIL UNDER PINE, HEMLOCK, AND MAPLE COVER

Abstract

Soil samples, taken by horizons, were obtained from the University of Toronto Forest near Dorset under stands of maple, hemlock, and pine. Counts of bacteria, actinomycetes, and fungi made by the plate method indicated that in general the organic layer contained the largest population, and also that in the organic layer under conifers the fungi exceeded the combined counts of the other two groups, whereas under maple the bacteria predominated. Using the perfusion method, nitrification did not occur to any extent in these forest soil samples except when lime was added, and even then nitrification started very slowly unless a few crumbs of garden soil were added, presumably as a source of active nitrifying bacteria.