Scientists create biodegradable sensors for precision agriculture

Researchers at Osaka University have developed a soil moisture detection technology based on mostly biodegradable sensors. Sensors in agricultural applications are generally used in high density and need to be removed after use. This new approach proposes a hyper-dense and sustainable system that combines simplified degradable sensors, a wireless power supply and information collected in thermal camera images.

The dense installation of sensors in agriculture is limited by sustainability. Collecting and disposing of used sensors is often a problem. The researchers talk about previous studies, for example, which spread countless sensors as plant seeds, yet eventually had to be collected because they were not degradable. “In other words, the recovery and disposal of sensors is frequently a bottleneck that limits the density and wider application of sensors in agriculture,” they comment.

According to the Japanese scientists, most of the sensor components are biodegradable, while the waste material has minimal adverse impact on the environment. In addition, the fertilizer component in the substrate helps to stimulate plant growth.

The new Japanese sensors use a biodegradable nanopaper substrate, natural wax and an environmentally friendly tin conductor line, according to the researchers. The sensors emit a thermal signal based on the soil’s moisture content. Simultaneously, the thermal camera collects data on the moisture content and the location of the sensors.

Scientists have focused their study on soil moisture sensors, which are crucial in agriculture. They can be distributed throughout the plantations, in large numbers, as if they were fertilizers. From there, the sensors receive energy from wireless power supplies, activating their heaters. The efficiency of energy transmission to the sensors varies with the moisture content of the soil surface, and this efficiency of energy transmission is reflected in the temperature of the heater. Therefore, the moisture content of the soil can be determined using a thermal camera based on the critical points detected. The position of the detection is determined precisely based on the relative position of the camera and the soil surface.

After a certain period of use (for example, at the end of a season), the sensors can be cultivated so that fertilizing components from the paper substrate are released into the soil.

The sensors are powered by a wireless power source coupled with magnetic resonance. According to the researchers, the proposed system can be developed further, especially in terms of the configuration of the sensors. In the study carried out, the sensors were placed in optimal positions and angles for wireless power transmission. In real agricultural applications, it is not easy to keep the soil surface smooth, so the sensors and the power transmission system must be improved to accommodate uneven terrain and changes in the angle of the transmission coil.

In addition, a uniform power supply needs to be developed to support numerous sensors and overcome a potential obstacle in scaling up the proposed system. Degradable sensors also need to be optimized to adapt to the target crop and the installation site.

The scientists point out that although the concept introduced is based on agricultural applications, its use is not limited to this field and can be extended, for example, to the world of logistics, where large volumes of sensors are needed to track assets.

The study was recently published in Advanced Sustainable Systems.

Precision agriculture market

Precision agriculture, or smart agriculture, is characterized by the implementation of advanced technologies such as the Internet of Things (IoT), sensors and wide-ranging networks with low energy consumption, Artificial Intelligence (AI) and satellites, which help to raise the productivity and sustainability levels of crops and livestock. In general, these technologies help reduce waste by providing information on irrigation water, fertilizers, nutrients, herbicides and pesticides, as well as automating processes.

According to research by Straits Research, this is a market that is expected to reach US$66.8 billion worldwide by 2030, with a compound annual growth rate of 18.4% in the forecast period starting in 2022. North America is the most advanced region in terms of digital technology.

The market can be divided into hardware systems, software and services. The hardware segment leads smart agriculture, followed by services. North America is the most advanced region in agricultural technologies.