Feedback of abuscular mycorrhizal fungi on interactions between maize/fababean and maize/barnyardgrass

【Objectives】 Arbuscular mycorrhizal fungi (AMF) plays an important role in contributing to plant growth in agro-ecosystems. Feedback of AMF communities pre-trained by different host plants and cropping types may influence the growth of subsequent plants, and intercropping system contributes to increase in yield and resource use efficiency. Therefore, understanding on feedback of AMF has a positive significance in elucidating yield increase in intercropping systems.【Methods】 Three isolates of AM fungi of Funneliformis mosseae, Rhizophagus intraradices and Claroideoglomus claroideum, three plant species of maize (Zea mays L.), fababean (Vicia faba L.) and barnyardgrass (Echinochloa crus-galli L.), and two intercropping systems (facilitation system of maize/fababean and competition system of maize/barnyardgrass) were established to investigate the feedback effects at the phases of two plant training and feedback.【Results】 Data showed that shoot biomass of maize decreased by 64.0% during training phase compared to monoculture in maize/barnyardgrass intercropping system, and the later increased shoot biomass of barnyardgrass by 47.8%. Maize and fababean respectively enhanced the shoot biomass of the plants by 21.7% and 38.3% based on the comparison between double plant cropping and monocropping. During the feedback phase, shoot biomass of maize, barnyardgrass and fababean increased by 602.3%, 80.6% and 21.1% respectively in monoculture system after inoculated with AMFs. In intercropping system, shoot biomass of maize increased by 613.1%, and shoot biomass of barnyardgrass by 80.7%, and shoot biomass of fababean by 21.4%. Monoculture maize exhibited a negative feedback, and the inoculation of AMF and intercropping with barnyardgrass or fababean relieved negative feedback in monocropping maize.【Conclusions】 The competition dominated in maize/barnyardgrass intercropping system compared to monoculture. Facilitation between maize and fababean enhanced the biomass of the respective plants. AMF inoculation increased the biomass of maize, followed by those of barnyardgrass and fababean. The inoculation of AMF, and intercropping with barnyardgrass or fababean relieved negative feedback of monocropping maize. In conclusion, AMF can relive negative feedback of maize and are attributed to the facilitation of maize/fababean intercropping system.