A sensor is a device that detects and responds to some type of input from the physical environment such as light, heat, motion, moisture and pressure. Agriculture sensors are sensors used in smart farming that help in heat detection, animal identification and health monitoring. There are several types of agricultural sensors including electronic sensors, location sensors, mechanical sensors, optical sensors, airflow sensors, and dielectric soil-moisture sensors. The use of remote sensing techniques to schedule nitrogen fertilization can assist in reducing the risk of harvest loss by providing a suitable rate of nitrogen at the time and place where it is needed by the crops. Precision agriculture entails the use of sensor technologies for nutrient and pesticide application, yield mapping and prediction, irrigation control, and soil sensing. This book contains some path-breaking studies on the application of sensors in agriculture. It will serve as a valuable source of reference for graduate and postgraduate students.