Next-Generation Agricultural Soil Science: From Rhizosphere Ecology and Soil Microbiomes to Climate-Resilient Farming

Nanofertilisers are being developed to improve the synchrony between nutrient supply and crop demand, reduce nutrient losses, and enable lower-dose foliar or soil applications. Yet the term encompasses chemically and functionally dissimilar products, from nanoscale nutrient oxides and apatites to nutrient-loaded nanocarriers, nanohybrids and commercial liquid formulations. This heterogeneity has encouraged broad claims that are not always supported by nutritionally equivalent controls or field-scale evidence. This critical narrative review evaluates the agronomic potential, nutrient-use efficiency and environmental safety of nanofertilisers, with emphasis on the distinction between material properties, nutrient delivery mechanisms and demonstrable farm-level benefit. Evidence was selected from peer-reviewed literature indexed in major open scholarly sources and assessed for formulation characterisation, comparator validity, nutrient-dose equivalence, study scale, nutrient recovery, environmental relevance and independent replication. The evidence supports a conditional rather than universal advantage. Nanoscale zinc, iron and phosphate systems can improve nutrient availability or biofortification in specific crop–soil combinations, while slow-release nanohybrids can alter nutrient-release kinetics. Recent multi-location and multi-season field studies of nano-urea and nano-diammonium phosphate indicate that moderate reductions in conventional nutrient inputs can sometimes maintain yield when nanoformulations are used at appropriate crop stages. Conversely, aggressive substitution, poorly matched controls and efficiency metrics that increase automatically as fertiliser dose declines can overstate performance. Nanoparticle uptake also cannot be inferred solely from plant response because dissolution, transformation and ionic uptake may dominate. Environmental advantages are plausible when total nutrient loading and losses decline, but nano-specific fate, soil microbial effects, long-term accumulation, residue speciation and food-chain exposure remain incompletely resolved. Progress therefore depends on nutrient-equivalent field comparisons, rigorous particle characterisation, isotope or speciation methods, full nutrient budgets, realistic ecotoxicology and independent multi-environment validation. Nanofertilisers should be evaluated as formulation-specific nutrient-management technologies rather than as a single superior class of fertilisers.