Application of mineral phosphorus fertilizer influences rhizosphere chemical and biological characteristics

Soil microorganisms directly participate in phosphorus (P) cycle, which in turn affects crop yield and quality. However, how biological and chemical parameters respond to mineral P fertilizer application rates in rhizosphere soil remains unclear. Here, a pot experiment was conducted to investigate the effects of different mineral P fertilizer application rates (0, 60, 120, and 300 kg P2O5 ha−1) on soil chemical properties and bacterial community in maize rhizosphere in a Mollisol. With increasing P fertilizer rates, soil organic carbon concentration decreased, while soil Olsen P and inorganic P and organic P (Po) fractions concentrations increased. High-throughput 16S rRNA gene sequencing showed that the relative abundances of some beneficial bacteria (Anaerolinea, Anaeromyxobacter, Kaistia and Rhodobacter) significantly increased with reduced P fertilizer rates, and meanwhile those of other beneficial bacteria (Mesorhizobium, Microvirga, Rhizobacter and Skermanella) significantly decreased under high P fertilizer rates. Redundancy analysis (RDA) showed that labile Po was the main driver of the differences in bacterial community structure. Bacterial community diversity and composition significantly and indirectly affected maize yield via octacalcium-bound P, occluded Fe/Al-bound P, labile Po, and moderately labile Po. The results suggested that reducing P fertilizer rates can promote beneficial bacterial growth and increase bacterial community diversity.