| The effects of several silvicultural practices on soil microbial functional diversity and community structure were assessed using sole-carbon-source utilization (SCSU). Microorganisms were extracted from soil samples and inoculated into Biolog gram-negative microplates. Optical density values were analysed by principal component analysis (PCA) and diversity indices calculated.; Soils from clear-cut, clear-cut followed by prescribed burning, clear-cut followed by scarification or uncut control plots were examined. PCA resolved the microbial communities from the organic and mineral soils. Organic soil samples exhibited higher functional diversity than those from mineral soil. Scarified plots treated four years earlier showed lower functional diversity when calculated only using carboxylic acids as the carbon source.; Two plots, clear-cut alone and clear-cut followed by prescribed burning were contrasted. Organic and mineral soil samples from the burned plot showed lower microbial functional diversity when pooled samples, but not individual samples, were examined.; The effects of fertilization (Osmocote) and vegetation control by herbicide (Vision{dollar}rmsp{lcub}TM{rcub}){dollar} application were studied. Control plots and those receiving fertilization alone contained similar microbial communities. Vegetation control, particularly in combination with fertilization significantly altered the microbial community as evidenced by PCA and lower levels of diversity.; Soil microbial functional diversity was determined to be lower in a short-rotation intensive-culture plantation than a grass field and both were lower than an adjacent, mature red pine (Pinus resinosa) plantation. PCA resolved the red pine plantation from the other two sites.; Soil microbial functional diversity was also assessed along an 800 km climatic gradient between Prince Albert, Saskatchewan and Gillam, Manitoba, Canada. Microbial functional diversity decreased with increasing latitude and correlated positively with measures of atmospheric temperature and pH. Colour development rank plots were consistent with a trend of increasing environmental harshness moving north along the transect.; Soil acid phosphatase, alkaline phosphatase and arylsulfatase activities were examined in clear-cut, clear-cut followed by prescribed burning, clear-cut followed by scarification or uncut control plots. Burned plots showed lower soil enzyme activities 4 years after treatment. In a separate experiment, acid phosphatase activity was inversely related to soil pH, log of fire intensity, total surface fuel consumption and total fuel consumption. |
