Atmospheric deposition or flux of total reactive nitrogen (N) to the Earth’s surface, calculated for example as kilograms N per hectare and year (kg N ha-1 yr-1). Reactive N from the atmosphere can be deposited as gases (= dry deposition) and in precipitation (= wet deposition). Total reactive N includes oxidised N compounds as well as reduced N compounds. Oxidised compounds are here mainly nitrogen oxides (NOx; gases) and nitrate (NO3-; in precipitation). The main reduced compounds are ammonia (NH3; gas) and ammonium (NH4+; in precipitation)