| Abstract: | Abstract A comparison was made between three acidified, simulated rain treatments which have been used to assess the impact of acid rain on soil chemical and microbial processes. There were significant differences in effects on chemical and microbial characteristics of soil exposed to the three treatments due to differences in the rate of H+ ion application, even though the total quantity of protons supplied was the same in each case. An input of 30 cm of simulated rain of pH 3.0 over 6 months increased microbial activity and caused only slight changes in soil pH and soil nitrogen status. Treatments in which the rate of H+ input was accelerated by increasing solution volume, or acidity, inhibited microbial activity and caused soil chemical changes in excess of those produced by the more gradual yet equivalent H+ loading. We conclude that the effects of short‐term, accelerated acid treatments cannot be used to realistically forecast long‐term impacts of acid rain. The results of such experiments may be useful in identifying processes or parameters for studies of longer duration. |
