# Energy-Efficient Wireless Sensor Networks for Precision Agriculture: A Review
## 4 Agriculture Requirements for IoT  
The IoT represents the visibility of a group of systems, technologies, platforms, and design principles for joining things, depending on the physical surroundings, through the use of the Internet. PA is an application that can employ the benefits of IoT to increase production efficiency, improve the quality of yields, reduce the negative ecological impact, prevent the prevalence of plant-eating pests or plant diseases, alert farmers about farm fires [141], and increase the profitability of several agricultural production schemes. Agriculture involves farming, planting, and animal rearing, and it has grown under the scope of IoT recently [5]. Tracking of animals, monitoring of farms, and irrigation processes are the main domains of IoT for cultivation [142]. Furthermore, feeding, rearing, medication, and vaccination are essential applications of IoT in the agricultural domain [143]. Consequently, several IoT modular architectures have been proposed and implemented by scholars for PA monitoring (as presented in Table 8). Real-time ecological information can be remotely gathered from the agricultural surroundings based on different sensors, which transmit the information to be processed to determine problems, take required actions using actuators, or store data. Sensors in WSN can be employed to gather information about environmental and physical features, whereas actuators are used to respond to the feedback to control or to perform an action over the conditions (Figure 3, Part B). The use of sensors in agricultural applications poses a number of requirements, including gathering of soil, weather, and crop information; surveillance of agricultural areas, water and fertilizer requirements of diverse pieces of rough land, several crops on a single piece of acreage, different requirements of crops for unlike soil and weather circumstances, and eliminating of interactive solutions and relying on proactive solutions. All these requirements are applied and processed in parallel. Therefore, different sensors and actuators must be used to handle this information and respond to different conditions. Processed information can be utilized to make a decision instead of raw data of the sensor [132]. This information can be transmuted to the cloud computing via gateway for data processing and data storage, as shown in Figure 3 (Part C). Reference [144] proposed a modular architecture for a wireless sensor node implemented for PA applications. The sensors employed in this modular were soil moisture, temperature, humidity, and wind direction and speed sensors to monitor the agricultural environments. \"Adafruit Pro Trinket\" platform was selected for the data processing, and nRF wireless protocol was used as a transceiver to transfer sensor data to the gateway (i.e., Intel Edison to reduce the power consumption). The gateway  
Figure 3: Example of farm field-based Internet of Things (IoT) and provided by a solar cell battery charger: (**a**) Agriculture sensor node with related sensor and solar cell, (**b**) Sink and actuator nodes, and (**c**) Gateway node and cloud computing. was in charge of collected information from different sensors and passed the information to the cloud server. The proposed system resulted in improved crop quality and minimized negative ecological effect. In [145], the usage of water in smart irrigation systems was controlled based on developed IoT platforms. A cloud agriculture field-monitoring scheme was designed and implemented to enable the farmer to monitor the soil condition. Soil moisture and weather temperature were monitored to automate the irrigation system in farm while minimizing water consumption, which led to reduced cost and maintained environmental benefits. The proposed water irrigation system included three main parts: a WSN and actuator, a cloud platform, and user application.