Biological Properties of Some Prince Edward Island Soils: Relationship Between Microbial Biomass Nitrogen and Mineralizable Nitrogen

The mineral N flush, a measure of microbial biomass N, and the N mineralization potential (N o ) were determined in eight representative agricultural soils (Humo-Ferric Podzols and Gray Luvisols) of Prince Edward Island. The acidic (pH 5.0–5.8) soils, varying in texture from loam to loamy sand had an organic C range of 0.75–2.74%. Both mineral N flush (4–38 μg N g −1 soil) and the percentage soil organic N in the mineral N flush (0.4–2.0%) were relatively low compared to other studies. This observation was related to the generally low pH range of these soils. Potentially mineralizable soil N (N o ) ranged from 44 to 247 μg N g −1 and accounted for 4.5–13.3% of the total soil organic N. The N o was closely related to the mineral N flush (r 2 = 0.94) but poorly related to percent organic matter (r 2 = 0.26) or organic N (r 2 = 0.38). The results indicate that for these soils of similar properties, with low levels of residual mineral N, the mineral N flush could be utilized as an indirect measure of the soil N mineralization potential.