From synthesis to soil: transformations and impacts of nanoparticles in agroecosystems

Nanoparticles (NPs) have emerged as transformative agents in agriculture, offering promising applications in nanofertilizers, nanopesticides, and soil amendments. However, significant knowledge gaps persist regarding the long-term impact of engineered NPs on soil health, including microbial networks and biogeochemical fluxes. Despite their potential to enhance nutrient use efficiency, promote crop resilience, and support sustainable farming, the interactions of NPs with soil matrices, especially their transformations, persistence, and ecological implications, are not fully explored. This review addresses these gaps by providing an in-depth analysis of current research on NP transformations, reactivity, and fate in soil environments. We classify NPs based on their synthesis precursors (natural vs. synthetic) and examine how surface charge, structural properties, and stability govern their interactions in soil. Key mechanisms of soil-NP interaction are explored across three transformation pathways: physical (aggregation, sorption), chemical (dissolution, redox processes), and biological (microbial transformation, enzymatic degradation). We evaluate the cascading effects of NPs on soil physicochemical and biological integrity, including alterations in microbial biomass, diversity, enzyme activity, nutrient cycling, and respiration. Drawing on diverse laboratory and field studies, this review highlights sustainability concerns related to NP synthesis and application, analyzes potential ecological impacts, and advocates for green synthesis strategies alongside risk-mitigation regulatory approaches. By integrating current insights and outlining critical research needs, this review provides a framework for the responsible implementation of nanotechnologies in agriculture, bridging the gap between innovation and sustainable soil management, with particular attention to preserving soil fertility and ecosystem functions in the context of sustainable and regenerative agriculture.