Exploring the Potential of CuS Nanoparticles for Agriculture: Functions, Implications, and Research Gaps

Abstract Copper (Cu) and sulfur (S)-based compounds have long been used in agriculture, yet their conventional soluble formulations often require repeated application and can contribute to off-target environmental loading. In recent years, nanoforms of Cu and S have been explored as alternative agricultural materials due to their reactivity, release kinetics, and biological interactions, which can differ markedly from those of bulk or ionic counterparts. Building on this progress, this review examines the potential of copper sulfide nanoparticles (CuS NPs) as an emerging material that integrates micronutrient chemistry, redox activity, and nanoscale functionality. The number of studies directly evaluating CuS NPs in agriculture remains relatively limited, but existing reports suggest three main application pathways: as antifungal/antibacterial agents, as nanocarriers for pesticidal active ingredients, and as controlled nutrient-delivery platforms for plant-relevant elements. Several studies have reported promising agronomic performance of CuS NPs compared to Cu-containing NPs and synthetic pesticides. However, results are highly context dependent. This review identifies key gaps in benchmarking, mechanistic validation, and fate assessment under realistic soil–plant exposure scenarios. Such studies are required to strategically design and assess CuS formulations that will deliver tangible agronomic benefits without unacceptable environmental risks.