Soil solutions and surface water analysis in two contrasted watersheds impacted by acid deposition, Vosges mountains, N.E. France: interpretation in terms of Al impact and nutrient imbalance.

Two acid watersheds in the Vosges mountains (N.E. France), one with a podzol, the other with an acid brown soil, were monitored by analysing soil solutions and two related springs for total chemistry and Al speciation. High concentrations of inorganic Al did not occur in the podzol upper horizons but were evident in the corresponding spring, together with low concentrations of Ca. In the acid brown soil area, high concentrations of inorganic Al occurred in the leaching water draining the upper soil horizons, but not in the undrained water nor in the spring, the latter exhibiting rather high Ca content. In both watersheds, needle yellowing in conifers could be observed and might be ascribed to Mg deficiency rather than to Al toxicity.