Abstract: 【Objective】 Arbuscular mycorrhizal fungus (AMF) is one of the most important soil beneficial microbe in natural ecosystem. It can effectively promote the nutrition absorption of plants and also regulate the interspecific relative competition ability and nutrition competition ratio between plants by redistributing water and nutritive elements between host plants at the intercropping level. To study the effect of AMF inoculation and different intercropping patterns on the interspecific relative competition ability and nitrogen (N) competition ratio between intercropping maize (Zea mays L.) and soybean (Glycine max L.) growing on the purple soil, and provide a scientific basis for the regulation of nutrient resource utilization and competitive effect between crops. 【Method】 A pot experiment with three different intercropping patterns (no separation, nylon net separation, plastic-film separation) and different AMF treatments [no AMF (NM), Glomus etunicatum inoculation (G.e)] was conducted to analyze intercropping plant growth and N nutrition status, which in order to quantify the effects of AMF treatments and intercropping patterns on the interspecific competition ability and N competition ratio between maize and soybean. 【Result】 The results showed that under the same intercropping conditions, maize always had a stronger competitive advantage, soybean showed a competition disadvantage. The interspecific competition ability and N competition ratio between maize and soybean under G.e-no separation treatment both were the highest. Whether AMF inoculation or not, N concentration, N uptake and the root biomass of maize plants were all in the order of no separation pattern nylon net separation pattern plastic-film separation pattern, while soybeans showed an opposite trend. In comparison with NM, AMF inoculation significantly promoted the interspecific competition ability and N competition ratio between maize and soybean, so that shoot and root biomass of maize was increased by 20.48% and 23.33%, respectively, under no separation patterns, and shoots and roots N uptake were also improved by 64.20% and 34.61%, respectively. For soil available N content, G.e-no separation treatment significantly improved N uptake of maize and soybean in intercropping of maize and soybean, and decreased soil available N content, which reduced soil N residue. 【Conclusion】 In conclusion, different competitive ability of maize with soybean was different in all intercropping patterns, but maize was always in a stronger competitive advantage than soybean. AMF inoculation also improved the interspecific competition ability and N competition ratio of maize to soybean significantly. These revealed that AMF played an important ecological significance in regulating resource utilization between different plants and maintaining the diversity of the crop plants in farmland.

Key words: arbuscular mycorrhizal fungus, intercropping patterns, purple soil, interspecific competition, maize, soybean