Surface - atmosphere exchange of ammonia over grazed pasture

This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.<br/>Ammonia exchange fluxes over the grass pasture of a research farm for dairy cattle breeding at Zegveld (the Netherlands) were measured continuously from July 1992 until July 1994. The main objective was to investigate the long term values and general patterns of the net contribution to atmospheric ammonia provided by exchange with such pastures. This is important for assessments of the export of ammonia from emission regions to natural areas that are sensitive to eutrophication and acidification.