Abstract
Earthworms can convert the organic phosphate compounds into ones available for plants. The arbuscular mycorrhizal fungi (AMF), which are symbionts that colonize plant roots, can promote the growth of host plants by absorbing and then providing phosphorus to plants. To investigate the effects of AMF and earthworms on pasture growth, with bahiagrass (Paspalum notatum) as the host plant, the earthworm Eisenia fetida, and two AMF species, Gigaspora margarita (Experiment 1) and Rhizophagus irregularis (Experiment 2), were used. There were four experimental treatments: control (C), earthworm addition (E), inoculation with AMF (M), and both AMF inoculation and earthworm addition (M+E). In the case of G. margarita, at 9 weeks, the dry weight, phosphate absorption, and nitrogen absorption of the bahiagrass were significantly larger with M treatment than with E or C treatments; it was largest with M+E treatment. In the case of R. irregularis, they were significantly larger with AMF inoculation. On the whole, the plant growth tended to be larger in the order: C, E, M, M+E. These results suggest that the growth of the grasses were promoted by AMF and earthworms coexisting in the soil rather than by AMF or earthworms alone, although the size of the effects were different, depending on the AMF species.
