Occurrence of polymerized silicic acid and aluminum species in two forest soil solutions with different acidity

We found a positive relationship between the occurrence of PS and the saturation degree with respect to secondary Al-silicates. Thus, we suggest that PS may even indicate precursors for the formation of secondary Al-silicates. In accordance with this concept, our results show that PS preferentially occurred in the upper B1 horizons, where low pH and high Al content may prevent its destruction.