Nanotechnology-Based Smart Sensors for Early Prediction of Crop Stress in Paddy Fields

Rice (Oryza sativa L.) is one of the most important staple crops globally and plays a central role in food security, particularly in Asian countries. Paddy cultivation is highly sensitive to environmental variations, soil nutrient imbalances, pathogen infections, and climatic fluctuations. Conventional crop monitoring methods depend mainly on visual symptoms and laboratory analyses, which often detect stress only after physiological damage has progressed. Recent developments in nanotechnology have led to the emergence of smart sensors capable of detecting subtle biochemical and physiological changes in plants and soil at very early stages. Nanotechnology-based smart sensors offer high sensitivity, rapid response, portability, and real-time monitoring capability. These sensors can detect parameters such as nutrient levels, moisture stress, phytohormones, reactive oxygen species, and pathogen biomarkers. Integration of nanosensors with Internet of Things (IoT), wireless communication, and data analytics has strengthened precision agriculture and early stress prediction systems. This chapter discusses the principles, types, working mechanisms, applications, advantages, limitations, and future prospects of nanotechnology-based smart sensors in paddy fields.