Comparison of Al speciation and other soil characteristics between meadow, young forest and old forest stands

Generally, in all studied stands majority of Al in aqueous extract is in the Al(X)1+ form, which indicates that a large amount of mobile Al is bound in organic complexes. It suggests that actual toxicity is rather low. On the other hand, we have proved that majority of KCl-extractable Al exists in Al3+ form. Thus we can conclude that disturbance of existing equilibrium may cause massive release of highly toxic Al3+ from soil sorption complex to the soil solution, and consequently it can endanger the whole ecosystem. Moreover, continuous soil acidification accelerated by anthropogenic factors leading to Al mobilization represents a chemical time bomb.