|Matzner, E: Factors controlling Al-activity in soil solution in an acid forest soil of the German Solling area, Z. Pflanzenernährung Bodenkunde, 155, 333-338 (1992)|
The forests of the Gcrmvl Solling area arc heavily impacted by acidic deposition. Analysis of soil solutions derived froin suclion lysimelers in the field reveal strong vertical gradients of Al-activity in the soil solution and increasing activity with soil depth. Temporal pattern of Al- activity in soil solutions under field condilions cannot easily be predicted by equilibrium models using AI(OH)j dissolution. Percolaling disturbed soil samples under laboratory conditions with artificial acid soil soluiions undemturaied to AI(OH), solids resulted in high rates of A1 release in the 30-40 cm layer and revealed AI(OH), as a possible Al-activity controlling solid. The laboratory findings are not in coincidence with field observations. This discrepancy with respect to [he regulation of Al activity in the 3040 cm layer is attributed 10 the effect of soil SINC~U~~ and the interaction of rnacropores and micropores under field conditions. A1 activity of the soil solution in the 0-10 cm layer seems lo be regulated by exchange reactions with organic substances.