Plants are necessary for the survival of all living organisms on the planet. They provide 98 percent of the oxygen we breathe and 80 percent of the food we eat because they are the foundation of the trophic network. Plants are also important in the interactions between humans, animals, and the environment, as they provide drugs, textile fibers, and other necessities for human life.
Unfortunately, insect abundance and abiotic factors such as salinity, radiation, temperature (T), and relative humidity (RH) extremes may significantly impact plant survival. Pathogens, pests, and climate change are all causing new plant diseases, posing a serious threat to plants.
According to the Food and Agriculture Organization (FAO), 40% of crop productivity is lost each year due to plant pests, diseases, and environmental stresses caused by climate change, wreaking havoc on agriculture and people’s nutrition and food security.
The 2030 Agenda with the Sustainable Development Goals recognizes the central role of agriculture in increasing competitiveness and productivity at the plant level in a sustainable way to reduce crop losses and poverty.
To achieve these goals, the agriculture industry is undergoing a Smart Farming revolution, in which novel sensors are combined with image processing, big data, and cloud computing to measure plant growth and environmental parameters such as temperature, solar radiation, relative humidity, and mineral nutrition.
Contactless methods such as spectroscopy, airborne/satellite imagery, and machine vision systems are used in state-of-the-art technologies to measure plant physiology and environmental factors quantitatively.
In contrast to traditional methods, novel techniques such as wearables and skin-mountable devices developed for humans have recently been applied to plants. The sensors are directly placed on the surfaces of plant organs such as leaves and stems, and they detect the status of plant health by profiling various trait biomarkers and microenvironmental parameters, transducing biosignals to electric readout for data analytics, using wearable technology that has recently been developed for human health monitoring.
Wearable sensors offer several advantages, such as helping farm management in smart agriculture or guiding botanists to understand growth needs. Tiny wearable plant sensors can detect transpiration from plants without affecting plant growth or crop production. This technology could open a new route in environmental monitoring.
However, at the moment, its use seems still limited at understanding some physiological responses of the plant (water, nutrients, light, etc.) as well as supporting biomonitoring. On the other hand, the plant’s response is often poorly specific in physiological activity, resulting in only a possible generic stress condition, more complicated to analyze when the stress factors are more than one and of different orders, abiotic and biotic. However, new scientific advances, testing crops for diseases or pesticides, could also be supported with this kind of technology.
Unexpectedly, fiber Bragg gratings (FBGs), widely used in health monitoring applications ranging from civil infrastructure to the human body, are a promising solution for developing plant wearables. The promising results show that FBG-based sensors can be used in real-world situations, and they hold the promise of improving continuous and accurate plant health growth monitoring techniques.
