Aims Mycorrhizal fungi can re-distribute nutrients among plants through formation of underground common mycorrhizal networks and therefore may alter interspecific plant competition.However,the effect of ectomycorrhizal(EM)fungi on interspecific plant competition in subtropical forests is poorly understood.In this study,we investigated the effects of EM fungal identity and diversity on the outcome of interspecific competition of plant species in relation to different successional stages in a Chinese subtropical forest.Materials and Methods This study selected four woody plant species,i.e.a pioneer tree Pinus massoniana,a late-pioneer tree Quercus serrata,a midsuccessional tree Cyclobalanopsis glauca and a late-successional tree Lithocarpus glaber in a Chinese subtropical forest.The outcomes of interspecific competition were investigated in the seedlings of three plant pairs,i.e.between Cy.glauca and Pin.mas-soniana,between Q.serrata and Pin.massoniana,and between Li.glaber and Q.serrata in a pot experiment.In the Cy.glauca-Pin.massoniana combination,plants in monoculture and two-species mixture were uninoculated or inoculated with EM fungi Paxillus involutus,Pisolithus tinctorius,Cenococcum geophilum,Laccaria bicolor and a mixture of these four fungal species.In the Q.ser-rata-Pin.massoniana and Li.glaber-Q.serrata combinations,plants in monocultures and two-species mixtures were uninoculated or inoculated with EM fungi Pis.tinctorius,Ce.geophilum,La.bicolor and a mixture of these three fungal species.EM root colonization rate and seedling biomass of each plant species were measured,and the outcomes of interspecific competition were estimated using competitive balance index after 6-month cultivation.Important Findings All EM fungal inoculation significantly promoted a competitive ability of the mid-successional tree Cy.glauca over the pioneer tree Pin.massoniana compared with the uninoculated control treatment,and the extent to which EM fungi affected the outcome of interspecific competition was dependent on EM fu
Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affe
