Nitrogen uptake facilitation in soybean/maize intercropping system inoculated with rhizobium and arbuscular mycorrhizal fungi

Pot experiments with different root barriers between maize and soybean were carried out to investigate the effects of rhizobium, arbuscular mycorrhizal fungi and interaction of rhizobium and arbuscular mycorrhizal fungi on nitrogen uptake in a soybean/maize intercropping system. The results show that under the dual inoculation with Glomus mosseae and soybean rhizobium SH212, biomasses, nitrogen contents of soybean and associated maize are significantly increased. On the average, the nitrogen uptakes by soybean/maize intercropping system inoculated with both microorganisms are increased 22.6%, 24.0% and 54.9% compared to those of the inoculated with arbuscular mycorrhizal fungi, rhizobium and control respectively. Soybean facilitates nitrogen uptake of the intercropping maize. Arbuscular mycorrhizal colonization of the intercropping maize and nodule numbers of the intercropping soybean are increased significantly. These are the main reasons that net increases of nitrogen uptake by maize under the mesh barrier and no barrier treatments are 1.8 and 2.6 times than that of the control. And the net increases of N uptake by maize under the dual inoculation treatments are 1.3 and 1.7 times than that of the control respectively. These results suggest that the inoculation with both microorganisms in the intercropping system could improve soil nutrition efficiency and enhance productivity of the intercropping system by the synergy effects of rhizobium and arbuscular mycorrhizal fungi.