Studies of the effect of simulated acid rain on the ecological equilibrium of the soil system .1. Outline of the field experiment and reaction of soil pH to exposure to simulated acid rain

A six-year field experiment on simulated acid rain was performed. The soil was treated with sulphuric acid solutions of pH 2.5 and 1.4. After 11 months of the experiment, soil pH significantly decreased, reaching a level depending on the treatment system. In the case of the lowest acid concentration, soil pH was reduced from the initial value of 6.8 to the value of 6.0; in the case of the intermediate variant, pH decreased to 5.6, whereas at the highest acid concentration it decreased to 5.0. The differences between soil acidity in the individual variants persisted to the end of the experiment. Up to the end of the fifth experimental year, the pH of the soil continued to decrease, while in the last year the pH value increased, irrespective of the soil treatment regime.