Regenerative Soil Management: Restoring Soil Health, Biodiversity and Ecosystem Functions for Sustainable Agriculture

The rhizosphere offers opportunities to improve crop resource acquisition and stress management, but successful manipulation of root-associated microorganisms remains less predictable than the mechanisms proposed to explain their benefits. This critical narrative review evaluates how host traits, soil physical and chemical conditions, resident communities and management jointly determine the performance of rhizosphere interventions. Literature covering 2012 to 27 July 2026 was selected through targeted scholarly searches, bibliographic verification and qualitative appraisal of causal inference, experimental realism and agronomic relevance. The synthesis distinguishes mechanisms demonstrated in simplified systems from microbial establishment, functional activity, harvestable yield and independently verified environmental benefits. Genetic and chemical studies provide convincing examples of host-mediated recruitment, microbial regulation of root development and community-dependent disease suppression. Recent field studies also demonstrate conditional benefits from mycorrhizal inoculation, bacterial consortia and altered nitrogen cycling. Nevertheless, colonisation does not consistently translate into crop response, positive biomass effects cannot automatically be interpreted as grain-yield gains, and molecular indicators do not establish nutrient transfer or carbon persistence. Apparent disagreements frequently arise from differences in inoculant quality, soil resource limitation, resident-community competition, crop developmental stage and the chosen comparator. A staged evaluation framework is developed around diagnosis, mechanism, ecological compatibility, field benefit and sustainability accounting. It favours host and habitat management where useful functions are already present, and targeted inoculation where a defined functional deficit and a compatible establishment niche can be demonstrated. Priority research should combine strain-resolved tracking and direct process measurements with factorial, multi-environment field trials, independent prediction tests and transparent economic assessment. Rhizosphere engineering is therefore best understood as context-dependent agronomic design rather than the addition of universally beneficial microorganisms. Its contribution to sustainable production will depend on identifying where interventions work, explaining where they fail and demonstrating that resource savings persist without transferring costs to soil fertility, environmental quality or farmers.