Mainly, monitor conditions in the soil holds great promise in helping farmers use water more efficiently. Sensors can now be wirelessly integrated into irrigation systems to gain real-time insight into soil moisture content. Studies suggest this strategy could reduce water demand for irrigation everywhere 20% until 72% without interfering with day-to-day work in fields.
What is the Agricultural Internet of Things?
Even in arid places like the Middle East and North Africa, agriculture is possible with efficient water management. But extreme weather events due to climate change make that more difficult. Recurring droughts in the western US over the past 20 years, along with other disasters such as forest fires billions of dollars in crop losses.
Water experts have measured soil moisture for decades to make water management and irrigation decisions. Automated technologies have largely replaced hand-held soil moisture instruments, as it is difficult to perform manual soil moisture measurements in production fields in remote locations.
Over the past decade, wireless data collection technologies have begun to provide real-time access to soil moisture data, enabling better water management decisions. These technologies can also have many advanced IoT applications in public safety, urban infrastructure monitoring and food safety.
The Agricultural Internet of Things is a network of radios, antennas and sensors that collect real-time crop and soil information in the field. To facilitate data collection, these sensors and antennas are: interconnected wireless with agricultural machinery. The Ag-IoT is a complete framework that can detect farmland conditions, suggest actions in response, and send commands to farm equipment.
By connecting devices in the field, such as soil moisture and temperature sensors, it is possible to: manage irrigation systems and save water autonomously. The system can schedule irrigation, monitor environmental conditions and control of agricultural machinery, such as seed planters and fertilizer applicators. Other applications include: estimating soil nutrients and identify pests.
The challenges of taking networks underground
Wireless data collection has the potential to help farmers use water much more efficiently, but placing these components in the ground presents challenges. For example, at the Purdue ENT Lab, we found that when the antennas that transmit sensor data are buried in the ground, their performance characteristics change drastically depending on how moist the ground is. My new book, “Signals in the soil”, explains why.
Farmers use heavy equipment in fields, so antennas must be buried deep enough to avoid damage. As the soil gets wet, the moisture affects the communication between the sensor network and the control system. Water in the soil absorbs signal energy, attenuating the signals the system sends out. Denser ground also blocks signal transmission.
We have developed a theoretical model and an antenna that reduces the impact of the soil on underground communications by changing the operating frequency and system bandwidth. With this antenna, sensors placed in the top soil layers can provide real-time information about soil conditions to irrigation systems on distances up to 650 feet (200 meters)– longer than two football fields.
Another solution I have developed for improving wireless communication in the soil is the use of directional antennas focus signal energy in a desired direction. Antennas that send energy to air can also be used for long-distance wireless underground communications.
What’s next for the Ag-IoT
Cybersecurity is becoming increasingly important to Ag-IoT as it matures. Networking on farms need advanced security systems to protect the information they transmit. There is also a need for solutions that allow researchers and agricultural extension officers to aggregate information from multiple farms. Collecting data in this way allows more accurate decisions to be made about things like water use, while preserving growers’ privacy.
These networks must also adapt to changing local conditions, such as temperature, rainfall and wind. Seasonal changes and crop growth cycles can temporarily alter operating conditions for Ag-IoT equipment. Using cloud computing and machine learning, scientists can help Ag-IoT respond to shifts in the environment around it.
Finally, the lack of fast internet access still a problem in many rural communities. For example, many researchers have integrated wireless underground sensors with Ag-IoT in central pivot irrigation systemsbut farmers without high-speed internet access cannot install this kind of technology.
Integrating satellite-based network connectivity with the Ag-IoT can help disconnected farms where broadband connection is still not available. Researchers are also developing vehicle-mounted and mobile Ag-IoT platforms that use drones. Such systems can provide continuous connectivity in the field, making digital technologies accessible to more farmers in more places.
Abdul Salam is an assistant professor of computer and information technology at Purdue University.