Automation of agricultural activities based on the Internet of Things (IoT) can transform the agriculture industry from static or manual to dynamic and intelligent. Additionally IOT is a less labour intensive procedure decrease manpower involvement. Wireless Sensor Networks (WSN), Precision Agriculture (PA) are the primary cause of automation in the agricultural sector. PA involves in specialized sensors and algorithms which helps to receive the required amount of nutrients for maximizing the yield and maintaining sustainability. PA involves obtaining accurate information about the state of the soil, crops, and weather from the sensors placed in the fields. High-resolution photos of crops are taken with manned or unmanned satellites or aerial platforms. The photos are processed to retrieve data for future decisions. A review of close-by and far-off sensor networks in the field of agriculture is covered in this study, along with some issues and difficulties. This survey covers wireless communication technologies, sensors, and wireless nodes used to measure environmental behaviour in agriculture, as well as the platforms used to obtain spectral images of crops, the spectral images and WSN applications are used to analysis the typical vegetation indices. A wireless sensor network-based system is the initial module, and it tracks the condition of crops in realtime. The multi-spectral imagery obtained in the second module by a low-altitude remote sensing platform which processed to identify healthy and diseased crops. We also emphasize the outcomes from a case study and indicate the difficulties and directions we need to take moving forward.