By Scout Nelson
Researchers at South Dakota State University (SDSU) have developed new wearable sensors that can monitor corn stalk and ear growth. The technology uses laser-induced graphene to collect plant growth information and provide regular updates. This research could help plant breeders and agronomists better understand how corn responds to fertilizers, nutrients, and other treatments.
Farmers often need guidance on the best time to apply nitrogen and other fertilizers. They also need information about how different treatments affect crop growth. While general recommendations are available, continuous plant monitoring could provide more specific answers. The new sensors offer a way to collect detailed information about plant development and help researchers make better decisions.
New Sensors Use Laser Induced Graphene
Mazhar Sher, a biosensors engineer and assistant professor in SDSU's Department of Agricultural and Biosystems Engineering, began developing these sensors in August 2022 after joining the university.
The technology uses graphene, a material made from graphite. Graphene was successfully isolated as a single-layer sheet in 2004 by physicists Andre Geim and Konstantin Novoselov at the University of Manchester in the United Kingdom. Their research on graphene and its special properties earned them the 2010 Nobel Prize in Physics.
In 2014, researchers at Rice University introduced laser-induced graphene. They showed that a carbon dioxide laser could convert a material called commercial polyimide into porous graphene. This method provides a quick and scalable way to produce graphene structures.
Laser-induced graphene has several useful properties, including high electrical conductivity, a large surface area, flexibility, and high sensitivity. These features make it suitable for developing sensors that can collect different types of information.
Sher explained that similar sensor technology is already used in some wearable devices, including fitness trackers. Before joining SDSU, he also worked on sensors designed to monitor human diseases during his postdoctoral research at the University of Pennsylvania.
Technology Tracks Corn Stalk and Ear Growth
Wearable sensors for plants are still a developing area of research. However, Sher and his master's student, Chamika Kuruppuarachchi, have completed initial testing of sensors designed specifically for corn plants.
The research team developed sensors that measure changes in corn stalk and ear diameter as the plants grow. The sensors collect information every 10 minutes, allowing researchers to follow plant development more closely.
The research was conducted in Sher's biosensors laboratory at the Raven Precision Agriculture Center. Corn plants were monitored in the SDSU greenhouse during the testing process.
A special design helps the sensors remain attached to growing plants without restricting their development. The graphene sensors are connected to a food-grade silicone band. When the plant grows and the sensor bends, the connection remains in place.
The researchers also added a spring mechanism to the design. This allows the silicone band to expand as the corn stalk or ear increases in size. As a result, the sensor can continue collecting measurements without putting pressure on the growing plant.
Graduate Students Support Sensor Development
Graduate students have played an important role in developing and improving the technology.
Sikander Ameer, a former doctoral student who worked with Sher from August 2022 until graduating in December 2025, helped identify the best laser settings for producing high-quality graphene sensors.
According to Sher, laser power and scanning speed must be carefully adjusted to improve sensor sensitivity and reduce defects. Finding the correct settings helps create sensors that provide more reliable measurements.
Building on this work, Kuruppuarachchi expanded the research by developing laser-induced graphene sensors that can be worn by plants. He also helped design and connect the electronic systems required to collect, process, and report the information.
The collected measurements are stored on a microSD card, which is a small removable storage device used in digital equipment. The electronic system is designed to operate using batteries, allowing researchers to monitor plants during long-term experiments.
This setup makes it possible to collect and store plant growth information without requiring constant manual measurements.
Research Could Improve Crop Management Decisions
The researchers do not expect farmers to place sensors on every corn stalk in their fields. Instead, the main goal is to provide this technology to plant breeders and agronomists.
These professionals could use the collected information to study how plants respond to different fertilizers, nutrients, growing conditions, and other treatments. Continuous monitoring could help them understand plant development at different growth stages.
For example, researchers could compare corn growth under different nitrogen application schedules. They could also study how specific treatments affect stalk and ear development over time.
This information could help plant breeders identify useful plant characteristics and help agronomists develop more detailed recommendations for farmers.
Although the polyimide sheets used to produce laser-induced graphene cost less than one dollar, the technology is still in the research and development stage.
Sher hopes to patent the technology in the future. The next steps include conducting field trials in SDSU research plots and securing additional funding to continue the work.
Funding for the purchase of the laboratory's laser engraver came from the South Dakota Nutrient Research and Education Council, the South Dakota Agricultural Experiment Station and the Department of Agricultural and Biosystems Engineering.
Photo Credit: south-dakota-state-university
Categories: South Dakota, Crops, Corn, Education