A smartwatch can tell us the level of oxygen in our blood, when our sleep is restless or the number of steps we take in a day. Now imagine that kind of tracking ability for plants. By the time farmers see curling leaves or stunted growth in their fields, their crops may already have spent days under stress.
A new innovation in plant "wearable" sensors aims to catch those distress signals earlier—before the plant visibly suffers, allowing farmers to respond and help their crops thrive.
In a recent study, researchers created tiny tattoo-like sensors that adhere to leaf surfaces and a stretchable band that wraps around stems. Together, they track two vital signs of plant life—the temperature and humidity beneath the leaf's surface, and whether the stem is still growing. Even more striking, the system runs without an external battery, scavenging power from moisture evaporating from the plant itself.
The work is published in the journal ACS Applied Materials & Interfaces.
"The larger promise is not merely that one plant can wear one sensor," said Sameer Sonkusale, professor of electrical and computer engineering at Tufts and senior researcher on the project.
"It is that fields could one day contain networks of plant-level monitors, each reporting early signs of thirst, salt stress, disease or nutrient imbalance. Satellites and drones already give farmers a bird's-eye view. Plant wearables could provide something more intimate: the plant's-eye view."
Current methods for monitoring crops use satellite imagery and drones to get visible, infrared and microwave data that map greenness, uneven growth, temperature, pest damage, soil moisture and other big-picture measurements of crop stress. Soil sensors can measure moisture, temperature, pH and some nutrient levels. And weather stations provide information on air temperature, humidity, rainfall, wind and sun exposure.
While those measurements are useful, they focus on conditions that may affect the crops in the future or on an assessment of damage already done. "The leaf sensor is more of an early warning system showing how the plant is responding in the moment, before visible signs appear," said Nafize Hossain, a graduate student who led the research in the Sonkusale lab.
The sensors can also be extended to track other important indicators of plant health, such as levels of important nutrients and plant hormones that are early signals of root, leaf, stem and fruit growth, as well as responses to pathogens.
Source: Phys.org
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