Effects of experimental acidification and liming on soil organisms and decomposition in a Scots pine forest

The effects of artificial acidification and liming on soil organisms and decomposition rates were determined in a field experiment in a pine forest podzol. Acidification lowered the decomposition rate of both needle and root litter, whereas liming had less effect. FDA-active fungal lengths as well as bacterial numbers and cell size decreased in the acidified plots compared to the control. Liming had no marked effect on the microorganisms. There were significant changes in the functional characteristics of the bacterial population due to the acid treatment as determined by factor analyses. The abundance of enchytraeidae decreased drastically both in the acidified and the limed plots. The acidification caused an increase in numbers of collembola, which was entirely due to an increase in abundance of Tullbergia krausbaueri. The number of mites was unchanged but Trachytes sp. and Oppia obsoleta ad decreased in the acidified plots. The pH of the soil was only slightly lowered by the acid treatment, while liming increased the pH considerably.