Farming and agricultural production account for a substantial part of the global economic system, and most people rely on them for their living. In this perspective, real-time agricultural field monitoring and smart irrigation using modern technologies are now important for effective farming in green homes, smart cities, and rural areas. Water is an essential resource to be conserved using the newest technology. The Internet of Things (IoT) and Industry 4.0 enable smart farming, including using Quadrotor unmanned aerial vehicles (Q-UAV) with computer vision. The IoT-based smart irrigation management systems with real-time sensors and Q-UAVs have contributed to the optimum use of water resources in precision farming. The research presented an intelligent irrigation and field surveillance system using atmospheric and soil data such as temperature, humidity, salinity, wind speed, as well as photographs of the field using UAVs. The parameters mentioned above are available on the smartphone of the farmers using IoT and are hosted without any delay in the Firebase console. In addition to this, a user can control the water pump on various fields via Firebase Cloud Message platform. The intelligence and smartness of the proposed system are implemented with a powerful and low-cost platform Raspberry Pi 4B system on chip computer with Industry 4.0 standard dedicated for IoT, real-time embedded protocol interfacing, and computer vision applications.