Can Beneficial Microorganisms Reduce Phosphorus Application Rates in Common Bean (Phaseolus vulgaris L.) Cultivation in Sandy Soils?

Beneficial microorganisms enhance phosphorus (P) use efficiency in common bean, compensating for its shallow root system. Integrating biological approaches with reduced P rates optimizes plant growth, improves yield, lowers costs, and advances sustainable agriculture. This study aimed to assess the effects of seed inoculation with Trichoderma harzianum and/or Bacillus amyloliquefaciens associated with reduced P fertilization on common bean (Phaseolus vulgaris L.) agronomic and nutritional performance. The experiment was conducted under greenhouse conditions using a Quartzipsamment Entisol soil. Inoculation with B. amyloliquefaciens or T. harzianum, regardless of the P rate, as well as co-inoculation under the full phosphorus rate, increased grain yield by 64.4%, 31.9% and 49.4%, respectively, compared with the non-inoculated control under the full phosphorus rate. Regarding total phosphorus accumulation, inoculation with T. harzianum increased P accumulation by 90%, and co-inoculation increased it by 72%, compared with the non-inoculated control. The use of B. amyloliquefaciens and T. harzianum in common bean cultivation can enhance nutritional status (57% for total N accumulation, 40% for P, 93% for K, 33% for Ca, 31% for Mg, 50% for S) and grain productivity (44%), even with a 40% reduction in phosphorus fertilization in sandy soils with very low P availability, under greenhouse conditions.