Microbial strategies to alleviate phosphorus deficiency in African smallholder farms: Inoculation and soil microbiome enhancement

Background Phosphorus (P) deficiency is a major constraint to agricultural productivity in African smallholder farms, where nutrient-poor soils and limited access to fertilizers prevail. Sustainable solutions, including the utilization of microbial processes, are essential for overcoming this challenge. Method This review synthesizes field evidence on microbial strategies to address P deficiency, focusing on microbial inoculants as well as on soil management practices that enhance natural microbiomes. Results While the reviewed field studies offer valuable insights into agronomic practices that influence microbial activity and community composition, quantifying the specific contribution of microbial processes to plant P nutrition remains a challenge. Evidence suggests that the turnover of microbial biomass and the subsequent release of P, together with the role of mycorrhizal fungi in extending the root system, may contribute more significantly to plant P uptake than the solubilization of inorganic P. Conclusions Future research should prioritize comprehensive field evaluations of microbial inoculants and employ suitable analytical tools to gain deeper insights into the mechanisms underlying microbial P mobilization.