Wet deposition of nitrate and ammonium can be measured at the same time as sulphate and pH using a standard precipitation collector used by ECN (Sykes and Lane, 1996) and the acid deposition monitoring networks and is cost effective on this basis. It also allows an assessment of the ratio of oxidised (nitrate) to reduced nitrogen (ammonium). Acid deposition has been declining in recent years – by more than 50% over large areas of the UK between 1985 and 1999 (NEGTAP, 2001) – and detecting the anticipated recovery of soils and plant communities is.
