Nano-biosensors are used for real-time monitoring and enhancing the efficiency of fertilizer application. Nano-biosensors combine nanotechnology with bio-sensing elements to detect soil nutrients such as nitrogen, phosphorus, and potassium. In the past, fertilization techniques had many drawbacks, such as nutrient runoff, acidic soil, and environmental pollution. However, nano-biosensors have introduced new techniques that allow us to manage nutrients on-site rather than conducting extensive work in the lab. There are different types of nano-biosensors: electrochemical (measure electrical signals from biomolecule interactions, common in glucose sensors), optical (use fluorescence, surface plasmon resonance (SPR), or quantum dots for detection), and piezoelectric sensors (detect changes in mass or mechanical properties, used in pathogen detection). Nanoparticles and quantum dots have made sensors more sensitive, stable, and useful in real-world settings. However, some challenges still exist, such as high production cost, short sensor life span, and difficulties in understanding the data they produce. These issues made it difficult to use nano-biosensors on a large scale. We can track nutrients in soil by using nano-biosensors. This leads to better crop growth, less waste, and lower harm to the environment by making farming more precise. These sensors support global efforts to grow food sustainably and protect the climate.