Verifying the effect of acid precipitation on soil leachates: A comparison between published records and model predictions

A model for predicting the effects of acid precipitation on the acid (H⁺ + Al³⁺ + Fe³⁺- and base (Na⁺ + K + Ca²⁺ + mg²⁺)-cation losses from soils via leaching as function of time was verified by examining published results for one indoor and five outdoor lysimeter studies (with precipitation pH-values ranging from 2 to 6), and five watershed studies. In each case the predictions of the model were in acceptable (but not perfect) agreement with the observed acid and base cation losses. These studies were selected from other relevant studies because they nearly met the information requirements of the model. The prediction of the acid cation content of soil leachates is important for considering the generally negative effects of such cations (especially the dominating Al³⁺-ions) on plant growth and ground-, stream- and later water quality.