With growing concerns about climate change and overpopulation, scientists are exploring innovative ways to boost agricultural productivity. A team from Tohoku University has developed a new, leaf-mounted sensor designed to monitor plant health and improve resource management, potentially enhancing crop yields and meeting the increasing global demand for food.
Extreme weather events such as heatwaves, heavy rainfall, and droughts put stress on plants, reducing crop yields and threatening the health of farms, forests, and biodiversity. Current methods for monitoring plant health are often inadequate. While drones and aircraft can gather broad, surface-level data, they fall short in tracking individual plant responses over time. Traditional small sensors, which provide more detailed data, often require on-site personnel to install and monitor them, making the process inconvenient and costly.
“The traditional methods may work well for some purposes, but they are difficult to operate and quite expensive,” said Kaori Kohzuma, one of the researchers. “To monitor small changes continuously, we needed a new solution.”
To address this gap, the research team created a compact sensor that attaches to the underside of plant leaves. This device uses spectroscopic technology to measure leaf color without blocking sunlight, enabling it to monitor changes over time. The sensor, which is powered by a battery and has Wi-Fi capabilities, is waterproof and can operate outdoors for over a month, collecting valuable data during that time.
“Smart agriculture is a huge time-saver,” explained Ko-ichiro Miyamoto, another member of the team. “Farmers don’t have time to manually check every plant. This sensor provides real-time, fine-tuned readings of plant health, helping them respond quickly to areas where plants are under stress.”
In tests, the sensor was compared to a commercial spectrometer and showed promising results. It accurately distinguished leaf colors across seven out of eight detectable wavelengths, with readings at 620 nm closely matching those from commercial chlorophyll meters. Additional tests on an Arabidopsis thaliana mutant, which is sensitive to stress, showed that the sensor’s readings aligned with the plant’s stress responses, matching the commonly used Photochemical Reflectance Index (PRI).
The sensor was also tested in real-world conditions by attaching it to birch leaves during autumn. Over a two-week period, researchers observed changes in leaf color and chlorophyll levels, which indicated plant stress, and how these fluctuations were influenced by sunlight intensity.
“This affordable sensor is a promising tool for accurately monitoring plant health and stress using leaf color and light reflection data,” said Kohzuma. “Its low cost makes it possible to deploy multiple sensors in different locations, creating a network that enables simultaneous monitoring across a large area.”
This technology could be a game-changer for smart farming, forest health studies, and other applications where detailed tracking of plant health is essential. The research, which highlights the sensor’s potential to improve agricultural practices and better manage natural resources, was published in *Sensing and Bio-Sensing Research* on September 24, 2024.
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