Accurate and precise irrigation is one of the critical factors for smart agriculture to avoid poor irrigation coverage. We developed an intelligent irrigation system that can locate dry patches in an agriculture field and selectively irrigate the dry areas thereby reducing wasteful overlapping. The proposed irrigation system is aided by a drone (UAV) equipped with a Thermal Infrared (TIR) camera to support automated and remote controlled irrigation in an agricultural field. Drones navigate and capture aerial thermal images which are sent to the cloud through the inbuilt 4G cellular network adaptor, along with flight data (GPS coordinates, altitude, direction of drone). The altitude and flight path are achieved by the inbuilt barometer and GPS of the drone. The data collected from the drone is processed in real-time using an image processing module at the ground control station in order to estimate the location and area of the dry patches. Based on this, specific LoRa-enabled smart sprinklers are turned on. The smart sprinkler head receives a command that determines the duration, force and direction of watering. The field area is divided into small sectors so that a relatively balanced workload is distributed among a fleet of drones.