The role of detrital quantity and quality in forest floor N leaching was investigated in a litter manipulation experiment at a deciduous forest under chronic N deposition. Dissolved inorganic nitrogen (DIN) comprised the bulk of nitrogen leaching from the control except a short period following autumn litterfall. The dominance of DIN was strengthened by litter exclusion, whereas the addition of glucose or fresh litter led to a small increase in dissolved organic nitrogen (DON) and either a temporary or gradual reduction in NO3- release, respectively. Changes in soluble organic C and microbial C in the forest floor implied that increased availability of C sources might have enhanced microbial immobilization of DIN, either temporarily following glucose application or over the longer term following litter addition. The results suggest that detrital quantity and quality can play a crucial role in determining the balance between DIN and DON in N-enriched forest soils.
Bibliographical noteFunding Information:
We thank Uwe Hell for assistance in field sampling and Petra Dietrich, Kerstin Moser, and Bettina Popp for chemical analysis of our leachate samples. This research was funded by the German Ministry of Education, Science, Research, and Technology (grant no. BEO-51-0339476C) and the German Academic Exchange Service (DAAD).
- C limitation
- Dissolved inorganic nitrogen
- Dissolved organic nitrogen
- Forest floor
- N saturation