Global adoption of organo-mineral fertilisers: environmental and policy insights

This review compares organo-mineral fertiliser (OMF) adoption across regions and quantifies agronomic, environmental, economic, and policy outcomes. Regional drivers and barriers to adoption are identified to inform sustainable fertiliser strategies. A systematic analysis of 75 peer-reviewed studies (2010–2023) assessed nutrient losses, greenhouse-gas emissions, crop yields, and soil-health indicators. Life-cycle assessments and policy evaluations were integrated to enable comparison across agro-ecological zones and income levels. Precision-placed sludge-derived OMFs in high-income settings reduced nitrate leaching by ≈ 15 kg N ha⁻1 yr⁻1 while sustaining cereal yields. Field trials with biochar-enriched OMFs reported potassium-leaching decreases of ~ 50–77% and ~ 18% lower greenhouse-gas emissions; maize yields increased by ~ 20–30% under tropical trial conditions. Programmes combining biochar/struvite OMFs with precision application reported nitrous-oxide decreases of ~ 7–10%. In low-income settings, reported maize-yield gains with community-managed compost-plus-mineral packages are ≈ 25–40%, with accompanying improvements in soil organic carbon and water retention; poultry-manure-urea OMFs were associated with grain gains at lower cost in the cited trials. Internet-of-Things-guided nutrient delivery raised fertiliser-use efficiency by ~ 20% yet remains cost-prohibitive for many smallholders. Carbon-credit and nutrient-trading pilots were associated with improved project bankability where monitoring systems function. Heavy-metal contents in phosphogypsum-based OMF pellets and dust-explosion risks during biochar processing were reported within regulatory limits under standard mitigation. In West Africa, poultry-manure strategies were associated with rice-grain increases of ≈ 30% in Burkina Faso. Integrating high-tech precision methods common in the Global North with low-cost organic-recycling approaches used in the Global South can yield complementary improvements in crop productivity, nutrient retention and climate-change mitigation. Harmonised quality standards, smallholder-oriented credit and investment in rural logistics are identified as practical enablers of safe, scalable OMF deployment. Long-term field trials on OMF-microbiome interactions and carbon stabilisation, optimisation of region-specific slow-release formulations and carrier chemistries, MRV-light approaches for smallholders, and evaluations of blended finance.