『Abstract
　We investigated nitrogen leaching and input-output budgets from 12 small, upland headwater catchments with differing fractions of peat, heather and bare rock in SW Norway. A close relationship was found between annual inorganic nitrogen loss and the fractional cover bare rock explaining 74％ of the variation. It was not possible to distinguish between the N leaching from the peat and heather dominated catchments in this investigation. Nitrate loss was negatively correlated to the C/N ratio of the soil organic horizon. Lowest soil C/N ratios of the soil organic surface horizon occurred in catchments receiving the highest amounts of N deposition. Our data for Norwegian moorland are in agreement with previous investigations relating soil C/N ratio and N leaching in forest soils. Runoff from the catchments showed a seasonal pattern in NO3^- concentrations. The low values during the summer are presumably due to increased biological activity (plant uptake and immobilization by soil microbes). The winter and spring NO3^- concentrations in 2001 in all catchments were much higher than in 2000, perhaps due to soil freezing.

Keywords: acid deposition; ammonium; bare rock; heather; moorland; nitrate; peat; small catchment; total organic nitrogen; upland 』

1 Introduction
2 Material and methods
　2.1 study sites
　2.2 Geology and soils
　2.3 Meteorology, hydrology and atmospheric deposition
　2.4 Runoff and stream water chemistry
3 Results
　3.1 Hydrology and temperature
　3.2 seasonal variations in runoff
　3.3 N input/output budgets
　3.4 Regression analysis
4 Discussion
　4.1 N retention and losses - differences between the study catchments
　4.2 Small scale variations - the significance of land cover
　4.3 Climatic controls on nitrogen leaching
　4.4 Organic versus inorganic N
5 Conclusions
Acknowledgments
References