Exudate pulses throughout the entire growth period trigger the increase in maize phosphorus use efficiency by modifying soil keystone microbial taxa

Exudates are the medium through which plants adapt to complex soil environments, however, the mechanisms of how different types of root exudates increase maize yield and phosphorus (P) use efficiency (PUE) throughout the entire growth period remains unknown. In this study, we designed an experiment to examine the effects of continuous addition of exudate substances on maize growth and P uptake over the entire growth period. The addition of succinic acid, luteolin, and inositol significantly increased maize biomass, particularly root biomass. Specifically, the treatment with added succinic acid increased maize yield by 11.6% and PUE by 8%. Additionally, we found that different exudate substances significantly altered the soil bacterial and fungal communities, thereby increasing soil P bioavailability. The microbial co-occurrence networks revealed that Actinobacteriota and Proteobacteria keystone ASVs, enriched by the addition of succinic acid, luteolin, and inositol, were significantly associated with maize P uptake. Furthermore, at the V12 stage (Twelve leaves unfolded), the addition of exudate substances significantly increased alkaline phosphatase activity, and at the R6 stage (Maturity), soil available P content was significantly elevated, enhancing soil P bioavailability. These findings provide evidence for future exploration of the interaction mechanisms between plants and soil microbes and optimizing nutrient management strategies in farmland.