Dry deposition of atmospheric ammonia at Rothamsted in 1976 and 1977

Summary Soils at Rothamsted receive approximately 4 kg NH 3 -N/ha/year through dry deposition of atmospheric ammonia. The value is low compared with other nitrogen input processes and reflects the low concentrations of ammonia in the atmosphere. Rainfall is a major factor limiting dry deposition as it removes large amounts of ammonia from the atmosphere. Dry deposition of ammonia is a relatively unimportant source of combined soil nitrogen compared with other natural and artificial sources.