Effects of endogeic earthworms on soil processes and plant growth in coniferous forest soil

The effects of the endogeic earthworm, Aporrectodea caliginosa tuberculata (Eisen) on decomposition processes in moist coniferous forest soil were studied in the laboratory. The pH preference of this species and its effects on microbial activity, N and P mineralization, and the growth of birch seedlings were determined in separate pot experiments. Homogenized humus from a spruce stand was shown to be too acid for A. c. tuberculata. After liming, the earthworms thrived in the humus and their biomass increased (at pH above 4.8). In later experiments in which the humus was limed, the earthworms positively influenced the biological activity in humus and also increased the rate of N mineralizati…