Fluxes of NO3-, NH4+, NO, NO2, and N2O in an Old Danish Beech Forest

摘要: The fluxes of the major nitrogen compounds havebeen investigated in many ecosystem studies over world.However, only few has attention been drawn to theimportance minor gaseous compoundsto complete cycle. In Denmark a detailed study onthe cycle an old beech forest implementedin 1997 at Gyrstinge near Soro, Zealand. includesthe gases NO, N2O and water mediatedtransport NO3- NH4+. Measurementsof are performed withmicro-meteorological methods (eddy-correlation gradient)and with chambers. Water mediated encompass rain,throughfall, stem-flow leaching from root zone. Thehydrological model is verified by TDR measurements. findings show that total N input tothe floor throughfall stemflow was 25.6 kg Nha-1 yr -1, open field wet deposition withprecipitation 19.0 ha-1 -1. internalcycling measured as turnover oflitterfall plant uptake 100 -1and 14 respectively. ofthe NO were minorimportance for forest, NOxemission being <1 -1 N2Oemission soil 0.5 withno significant difference between dry soils.Concentrations NH4+ thesoil solution beneath rooting zone very small andconsequently almost negligible. It isconcluded mass balance this beechforest mainly controlled andwet large internal fast litterturnover. which currently exceeds critical loadby 5 -1is accumulated no nitrateleaching occurring.