Comparison of the Effects of Wet N Deposition (NH_4Cl) and Dry N Deposition (NH_3) on UK Moorland Species

Increases in N deposition (wet and dry) have been associated with a decline in semi-natural plant communities, adapted for growth on nutrient poor soils in the UK and Europe. The impacts of N deposition applied as either wet NH_4^+ or gaseous NH_3 on vegetation (7 species) from acid moorland in SE Scotland were compared in a dose-response study. Wet N deposition at 0, 8, 16, 32, 64, 128 kg N ha^−1 y^−1 was applied as NH_4Cl, and dry deposition as gaseous NH_3 (2, 6, 20, 50, 90 µg NH_3 m^−3) under controlled conditions in open-top chambers. A strong linear dose-response relationship (p