Effect of inoculation of AMF on plant growth and phosphorus utilization in intercropped maize under chamber phosphorus addition on red soils in Dianchi Watershed

Arbuscular mycorrhizal fungi (AMF) promotes growth of plants and increases utilization of phosphorus (P) and other nutrients of plants. Intercropping is an effective way promoting use efficiency of resources in both time and space. As the shortage of soil phosphate in different regions around the world worsens, more researches have focused on intercropping or mycorrhizal technology to strengthen soil P utilization and increase crop yield. Irrespectively, little has remained known about the effects of combined AMF inoculation and intercropping on plant growth and P utilization in sloping soils in Dianchi watershed. Plant growth and P utilization of maize (Zea mays L.) intercropped with soybean (Glycine max L.) or monocultured in red soils were investigated through the addition of different amounts of P to compartment chamber and different treatments of AMF inoculation in a root growth chamber. Three different P additions no P (P0), organic P (soy lecithin, OP50) and inorganic P (potassium dihydrogen phosphate, IOP50) with 50 mg(P)kg^-1 of soil, respectively and two AMF treatments no AMF (NM) and Glomus mosseae inoculation (GM) were set up. The results showed that among the composite treatments, both the shortest root length and largest shoot biomass of maize occurred under the GM-IOP50 intercropping treatment. For OP50 treatment, AMF infection rate of intercropped maize was significantly higher than that of monocultured maize. Regardless of P addition under intercropping, maize shoot biomass was obviously higher for GM treatment than for NM treatment. Then maize root biomass and plant height were significantly higher under GM treatment than under NM treatment. Root biomass was also highest under GM-OP50 intercropping treatment. For GM inoculation treatment, biomass for P0, IOP50 and OP50 intercropping treatments increased respectively by 45.98%, 111.33% and 33.56% over that of the corresponding mono-cropping treatments. With or without the addition of P under mono-cropping, P content in maize shoot was significantly higher for GM treatment than for NM treatment. Also irrespective of the mode of planting and addition of P, P content in maize root was significantly higher for GM treatment than for NM treatment. Regardless of P addition treatment, P uptake of maize shoot under intercropping with GM inoculation treatment was higher than that of the other treatments. Then shoot P uptake under IOP50 treatment was significantly higher than that under OP50 treatment. Under GM intercropping treatment, the specific absorption rate of P by maize root was significantly higher for IOP50 intercropping treatment than for OP50 intercropping treatment. Thus AMF inoculation, P application and intercropping modes respectively promoted plant growth to a certain extent. GM-IOP50 intercropping treatment performed best in terms of shoot growth and P uptake, which effectively strengthened P use in red soils in Dianchi Lake Basin.