A simple biomonitor for measuring ammonia deposition in rural areas

Summary Knowledge of the contribution of NH₃ to the total deposition of N in rural areas is sparse, because the determination of NH₃ deposition is costly and labour-intensive. A simple biomonitor consisting of barley plants grown in pots with an inert growth medium is therefore proposed for estimating total N deposition, including NH₃. The rise in total N of the plant-soil system reflects the deposition. The biomonitor was tested near a dairy farm. Different N contents in the green biomass reflected differences in deposition, and the deposition correlated very well with NH₃ levels in the area and in two background stations. The biomonitors were placed above the crop, the measurements thus representing total N at the edge of a plant community. In 1 month the deposition in the NH₃ plume was 8 kg N ha^–1.