The PGPB paradox: A critical review of field performance and practical constraints in agriculture

Abstract

While PGPB have historically been applied in agriculture, their formal recognition in the last century has driven intensive research into their role as sustainable tools for improving crop yield and stress tolerance. As they are primarily sourced from wild or native environments, the widespread enthusiasm has led to heightened expectations surrounding their potential, often based on the assumption that biological solutions are inherently safer and more effective than synthetic inputs. However, despite their popularity, increasing reports of inconsistent or limited performance under real-world, field conditions have raised critical questions about their credibility as biofertilizers and biocontrol agents. This commentary critically evaluates the reasons behind the limited success of PGPB in field settings, based on the latest scientific evidence. Particular focus is placed on the microbial conflict in the rhizosphere, the inability of PGPB inoculants to adapt in complex environmental conditions, limitations in modern agricultural practices, formulation challenges, and regulatory gaps. The paper recommends the need for a paradigm shift in PGPB research and deployment strategies to better align laboratory successes with the challenges and outcomes seen in actual field conditions. Such an approach is vital for reducing over-reliance on underperforming technologies and promoting more resilient, context-specific solutions for sustainable agriculture, especially in under-resourced regions.

Keywords: Field failure; PGPB; Rhizosphere; Soil microbiome; Sustainable agriculture.