Studies on the Relationship of Microbial Biomass to Primary Production in Three Spruce Forest Soils

Using a physiological method for measurement of microbial biomass in soils and production data from three spruce stands in the German IBP study site in Soiling, an attempt was made to relate yearly primary production values to the average quantities of microbial biomass in the organic matter layers (L + F + H) of the forest floors.

The Picea abies stands chosen for study were 39, 87 and 115 years old and contained a yearly average of 5.7, 2.6 and 2.1 mg microbial biomass carbon gdwt organic matter⁻¹. Evaluated on a m² basis, a direct correlation between primary production and microbial biomass in the organic layers was not evident, however, when the production capacity (above ground productivity per unit weight standing crop) was compared to the microbial biomass m⁻², a correlation could be established.