Drones will be increasingly important in crop production and research in the coming years, Jae Ryu believes.
The unmanned aerial vehicles even could replace manned agricultural aircraft within a decade, the University of Idaho researcher said.
Some farmers already use small drones to identify areas of water stress in the field, said Ryu, a Boise-based associate professor in the Department of Soil and Water Systems.
But bigger drones and payloads are often required for detecting nutrient shortages as well as the presence of insects and disease, and for spot-spraying a chemical, he said.
“At this point, it is still expensive,” said Ryu, whose largest drone is worth about $60,000 including its sensor package. “But large farms can consider getting this kind of equipment.”
Analyzing drone-collected images and data also requires additional time and special skills, he said.
Farmers can access equipment, facilities and human resources by partnering with the university, Ryu said. The data and contract or fee revenue support research advancement as well as current projects.
Drone use in agriculture has grown partly because satellite information is too coarse to use effectively for farm-scale decision-making, he said. With a drone, there are fewer physical constraints such as clouds, the user gets high-resolution images quickly, and “you can see a dime from the sky from maybe 200 feet off the ground.”
Hyper-spectral sensors can identify crop stress possibly caused by water or nutrient shortages, or pest and disease impacts. Ryu said hand-held versions excel at taking images anywhere in a crop, including pinpointing crop stress, and enable the user to move around a field easily.
By mounting the sensor on a drone, “we can basically identify a crop-stress area at farm scale,” he said. Light-spectrum data from the drone-mounted sensor can be cross-validated with information gathered by hand-held device, increasing data accuracy and utility.
In an onion field, for example, a hand-held sensor may find one light spectrum indicating crop stress from a lack of water and another spectrum showing stress from a nutrient deficiency.
“It is only identified locally,” Ryu said. “But the drone can tell them if this area is heavily affected.”
Spot spraying may require a heavier “freight” drone.
“Many Asian and European countries already are implementing drone-based spot spraying,” Ryu said. “That is my next project, to build a spot-spray drone to advance pest control in the Treasure Valley.”
He uses remote-sensing technologies and satellite images to view drought and characterize its impact on Western agriculture. He is working on using drone-mounted sensors to chart water quality, important in that detecting an issue early could reduce problems later, he said.
Drones, with their close-proximity imagery, also show promise in estimating grape and tree fruit productivity, Ryu said.
He is considering developing a drone workshop for farmers.