Nano-Enabled Precision Fertilization: A Critical Scoping Review and Research Roadmap for Operational Convergence

Nano-enabled fertilizers and precision agriculture are increasingly framed as complementary strategies to enhance nutrient-use efficiency and reduce environmental footprints. However, their operational integration remains unclear because precision denotes either spatial field management or targeted nano-enabled release. This scoping review evaluated whether nanofertilizers have been operationally integrated into spatially explicit nutrient-management systems. Systematic searches in Scopus and Web of Science, complemented by citation tracing, identified 60 reports representing 59 unique evidence units. An operational framework disaggregated integration into spatial decision-making (S), differential nano-enabled deployment (N), and spatially resolved outcome validation (O), with validation maturity coded from V0 to V6. Of the 59 evidence units, 52 (88.1%) represented conceptual convergence, five (8.5%) technological proximity without operational coupling, and only two (3.4%) advanced partial integration. The review did not identify a fully assessed study that demonstrated the complete S–N–O sequence. The two most advanced cases followed complementary pathways: S-N without spatial outcome validation, and S-O with uniform nano-input application. Citation tracing also revealed that secondary claims often overstate operational maturity relative to primary evidence. Closing this gap requires establishing field-scale S–N–O workflows that explicitly link spatial diagnosis, differential nano-actuation, and multi-zone agronomic and environmental validation.