Arbuscular mycorrhizal (AM) fungi are an important determinant of plant performance, and conversely their community composition greatly depends on host plants and their neighbors. Understanding how the interaction of host plants and their neighbors affects AM fungal communities in afforested zones is of primary interest in forest ecology. This study was conducted at a 10-year old long-term experimental site established on the Loess Plateau to evaluate the effects of different afforestation types on soil erosion, and roots and rhizosphere soils were sampled in monocultures and mixtures of black locust (Robinia pseudoacacia) and oriental arborvitae (Platycladus orientalis) to define soil propertied, AM fungal colonization level, spore density and communities.
Results/Conclusions
Oriental arborvitae, as the neighbor of black locust, reduced soil water, NO3-N and alkaline phosphatase activity, and increased soil Mn level compared with black locust monoculture; and black locust, as the neighbor of oriental arborvitae, increased soil water and NO3-N levels, but decreased catalase activity compared with oriental arborvitae monoculture. Neighboring oriental arborvitae only affected AM fungal community in black locust rhizosphere. For oriental arborvitae, however, growing in a mixture with black locust changed AM fungal colonization, sporulation and communities in the roots and rhizosphere. In particular, neighboring black locust modified the rhizosphere- and root-inhabiting AM fungal pool through improving soil NO3-N and water contents and reducing soil catalase activity, and the modification in the root AM fungal resource, especially the Glomus and Rhizophagus genera, further affected AM fungal colonization and sporulation under oriental arborvitae. All the results presented here suggest that both hosts and neighbors can largely affect AM fungal attributes mainly through changing soil nutrient levels and enzyme activity, whereas the reciprocal effects are not always symmetric.