The role of Athyrium distentifolium in reduction of soil acidification and base cation losses due to acid deposition in a deforested mountain area
The tall fern (Athyrium distentifolium Tausch ex Opiz) forms large stands in many deforested sites in Central European mountains. In the present study, we want to demonstrate that the effect of ferns on the leaching of nutrients is the same at low and high nitrogen (N) deposition. Free-tension lysimeters with growing ferns, and some with bare forest soil were installed in field conditions in 2006. We monitored the chemistry of lysimetric water at ambient and enhanced (plus 50 kg N ha-1) levels of N deposition during five growing seasons. Results indicate that during the growing seasons ferns slightly decreased of acidity and conductivity of lysimetric water and substantially reduced losses of base cations (Ca2+ and Mg2+). The concentration of leached base cations was three to seven times higher from bare forest soil than from lysimeters with ferns. Higher N accumulation in fern biomass coincides with lower contents of leached N in lysimetric water. The reduced losses of base cations were due to the ability of Athyrium to absorb and accumulate nutrients in large amounts in living biomass and in dead undecomposed plant matter and particularly in below-ground biomass.