COMPARISON OF NITROGEN MINERALIZATION IN FOREST FLOOR MATERIALS USING AEROBIC AND ANAEROBIC INCUBATION AND BIOASSAY TECHNIQUES

Abstract
Nitrogen mineralization in five forest floors of differing morphological characteristics was compared using a greenhouse plant bioassay and laboratory aerobic and anaerobic incubations. Forest floors dominated by F materials mineralized more N and had higher k values than those dominated by H. Plant N uptake in the bioassay was highly correlated with N mineralized during the laboratory incubations across all forest floors but was 50–80% lower than predictions based on first-order kinetic parameters derived from the aerobic incubation. The relationship between bioassay plant uptake and predicted N mineralization differed among forest floors, indicating that the effect of plants on dynamics of the mineralizable N pool differs among organic matter types. Differences in N mineralization characteristics between forest floor materials suggest that forest floor morphology may provide a basis for assessing site quality. Key words: Nitrogen, anaerobic mineralization, aerobic mineralization, bioassay, forest floor