Risk of damage to crops in the direct neighbourhood of ammonia sources.

In the Netherlands ammonia is emitted from several thousand sources (animal buildings, manured pastures, slurry storage facilities, etc.). Obviously, the ammonia concentrations are higher close to the source, but at this short distance vegetation has no special value in terms of nature conservation, as it mostly consists of ammonia-resistant agricultural crops. However, three crop categories include relatively sensitive species (fruity culture, glasshouse crops and arboriculture). This paper presents an estimation of the risk of ammonia damage to sensitive crops as related to the distance to the source, based on the mean and variation in emission, dispersion, regional background concentration, landscape characteristics and plant sensitivity. Some attention is paid to damage of natural vegetation and to risk-reducing measures (elevation of emission point, wind fence around the source). The goal is to provide information for regional and local officials and farmers who are dealing with risk evaluation, claims for damages, and environmental policy matters like stable reallocation