The fate of 15N-labelled nitrogen deposition in coniferous forest ecosystems

摘要: Abstract As part of four European ecosystem manipulation experiments in coniferous forests, field-scale 15N tracer have been carried out. The involved a year-long addition 15NH4+ and/or 15NO3− to throughfall at experimental plots with different N inputs. fate this applied the important ecosystems pools (trees, ground vegetation, forest floor and mineral soil), as well drainage was measured. About 10–30% added taken up by trees 10–15% retained soil. Both retention efficiencies were found be constant input. organic layer relatively high (20–45% applied) low inputs (0–30 kg ha−1 yr−1) but (10–20%) (30–80 yr−1). An inverse relationship between input loss found: losses increased function These results suggest that exceed capacity microbial population retain throughfall-N layer, result leaching increases.