Cropping and the diversity and function of bacteria in Pahokee muck

Abstract

The role of the soil bacterial populations of Pahokee muck in glucose and succinate oxidation, the bacterial diversity of this soil, and specific catabolic capacities of the bacterial isolates from Pahokee muck were examined. Measurement of 14CO 2 evolution from glucose and succinate in the presence of protein synthesis inhibitors suggested that the soil bacteria were responsible for 57–60% of this respiration. The bacterial diversity ( H') of soils from fallow, sugarcane ( Saccharum spp) and St Augustinegrass ( Stenotaphrum secundatum (Walt) Kuntz) fields were 2.76, 3.49 and 3.75. respectively, but rarefaction analysis of the data indicated that the diversities were not significantly different ( χ = 0.05). Analysis of the distribution of the isolates amongst the 21 phena from the three soil sample sites indicated that the structures of the bacterial communities of the cropped and fallow soils were very similar. These data suggest that the potential catabolic activities of the soil bacteria were the same in the soils from the fallow, sugarcane and grass fields. Differences in the environmental factors and population densities were responsible for the different enzymatic and respiratory activities observed in freshly-collected soil samples.