Mycorrhizosphere bacteria and plant-plant interactions facilitate maize P acquisition in an intercropping system

The intensive use of chemical fertilizer particularly phosphorus (P) to provide sufficient plant nutrients to meet the global food demand can deteriorate the quality of the ecosystem and are not affordable to farmers in low-resource environments. Additionally, low use efficiency of P in agriculture due to its low immobility in soil and rapid precipitation with soil minerals, which caused low bioavailable P content in soil. Therefore, a sustainable P use and management mode for cleaner agricultural production is an urgent issue to solve. Here we evaluated an alternative strategy to facilitate plant P nutrient availability with arbuscular mycorrhizal fungi (Rhizophagus irregularis) and their associated bacteria in cereal-legume intercropping based on a pot experiment. Plants were grown with or without Rhizophagus irregularis (AM) in pots against three different phosphorus levels and were inoculated with two bacteria strains (B). AMF root colonization and the influence of intercropping and microbial inoculation on plant growth and nutrient absorption were investigated. The findings showed that inoculated plants under the intercropping system produce the greatest plant growth responses and highest P uptake. The highest plant growth performance, soil P availability, and uptake were observed under the intercropping system with 30 kg P ha−1 (50% of the regular recommended P fertilizer rate) application. Further, we evaluated the influence of the microbial inoculation on mobilization of sparingly soluble phosphate. The results demonstrated a significant decreased in Al–P, Fe–P and Ca–P under the 30 kg P ha−1 fertilizer rate. Specifically, comparing with the control (Ctrl) there was 30.32% (AM) and 36.35% (AMB) reduction in Al–P, 44.53% (AM) and 45.11% (AMB) reduction in Fe–P, and 39.68% (AM) and 43.61% (AMB) decrease in Ca–P. These findings extend our knowledge regarding the significant role of plant-microbes symbiosis under intercropping system on sustainable crop production and nutrient (P) use efficiency.