Effect of mycorrhizal inoculation on growth and phosphorus accumulation of intercropped maize on purple soil

Arbuscular mycorrhizal fungi (AMF) plays a critical role in phosphorus (P) cycle in the soil-plant system. AMF can reduce P fertilization amount through improving utilization ratio of P fertilizer and activating soil P availability. Intercropping system of different crops also increases nutrient uptake and utilization efficiency compared with monoculture system. AMF inoculation in intercropping system to reduce soil P loss has become a research hotspot. However, the beneficial effects of combination of AMF and intercropping on plant growth and P accumulation have not been fully understood on the purple soil. In this study, growth and P accumulation of maize (Zea mays L.) intercropped with soybean on purple soil was studied through a pot cultural experiment under different root separation ways and AMF inoculation. Three inoculation treatments no AMF (NM), Glomus mosseae inoculation (GM), G. etunicatum inoculation (GE) and three roots separation ways (no separation, nylon net separation, plastic-film separation) were set up. The study may provide a theoretical basis for exploring P nutrient use efficiency of intercropping system with AMF technology. Results showed that differences in AMF colonization rate of intercropped maize among different roots separation ways were not significant under GM treatment, while AMF colonization rate was significantly highest under plastic-film separation and G. etunicatum inoculation (GE treatment). Different AMF treatments showed different effects on intercropped maize growth. GE and GM treatments under three roots separation ways showed obviously different advantages. Compared to NM treatment, GM treatment increased dry biomass and plant height of intercropped maize, improved P uptake under no roots separation; while GE treatment increased dry biomass, improved P uptake under nylon net separation of roots. Furthermore, P uptake amount of intercropped maize under AMF inoculation treatments were higher than no AMF inoculation treatments. The shoots dry biomass of intercropped maize was lower under roots separation treatments than not separation treatment, roots dry biomass showed opposite trend. Whether inoculating AMF or not, root P content and uptake were significantly higher under roots separation with nylon net, while root P uptake efficiency was significantly higher under combination of no roots separation and G. mosseae inoculation than under root separation. In conclusion, AMF inoculation could promote plants growth and roots P accumulation, and showed greater advantages under nylon net separation. Nylon net separation of roots significantly improved growth of maize. The treatment of GE inoculation plus roots separation with nylon net was the best one for intercropped maize growth and P accumulation, which could effectively control P loss from slope farmland in the Dianchi Lake Basin.