In a crop field cull, how do the knives of judgment distinguish saint from sinner? One of the current roadblocks to commercialization of robotic technology for tasks such as weed control is the ability of a machine to recognize crops growing among weeds in a natural environment. The solution may be found in the advent of novel fluorescent marker technology. Essentially, a robot asks questions and a plant responds with its precise location. It all happens with light.
The key concept of a seminal project led by Professor David Slaughter, UC Davis, Department of Biological and Agricultural Engineering, is to allow for direct signaling – making it easier for a computer system to identify which plant parts belong to crops and which to weeds. Slaughter has a large team working on the project, including researchers at the University of Arizona, Washington State University, UC Davis, and Aginnovation -- a corporate partner and founding member of the Centor Group, a global seed technology alliance of companies. Aginnovation has a proprietary seed technology, distinct from genetic engineering, which was developed for lettuce crops as an identifying marker that is safe on seed.
A fluorescent systemic marker is applied onto seeds through a seed treatment, seed coating or seed encrusting/pelleting and as it germinates, the systemic nature of the marker is drawn through the plant and extends to the foliage. The plant takes on a unique fluorescent appearance. When the plant is stimulated with a special color of light, it emits a fluorescent color. Essentially, it acts like a signal – a conversation.
The technology isn’t restricted to a particular crop type. Slaughter’s work is funded through USDA’s National Institute of Food and Agriculture program for specialty crops, and research is currently focused on vegetables, but the concept has cross-application in non-vegetable crops. “Historically, we’re thinking of a vehicle like a spray thinner in lettuce or our existing mechanical hoe systems pulled by a tractor – similar to pulling a planter,” Slaughter describes. “However, there’s nothing preventing these vehicles from becoming autonomous and able to move under their own propulsion.”
He hopes to have a prototype ready within two years, and a commercial product within five to 10 years. The current bottleneck involves identifying crops from weeds with a high degree of accuracy and doing so at a commercially viable speed, according to Slaughter. “Currently, the California lettuce industry uses commercial spray thinners with machine vision.”
Track & Trace
The fluorescent marker technology is part of Aginnovation’s Track & Trace Systemic Marking product line. The systemic markers were initially designed for anti-counterfeiting use by seed companies. “Fluorescence in the plant tissue can be observed like a glow-in-the-dark object through special optics under Slaughter’s design,” says Peter Marks, general manager of Aginnovation. “The systemic marker in the plant must be excited with a certain wavelength of light detected by a robotic machine. You can’t see the marker with the naked eye. By utilizing optics, we look for that particular marker and a given plant is noted for keeping, eliminating or maybe counting.”
The options for use of the technology have developed into a raft of possibilities: mechanical thinning, weeding, plot management, plant populations, and much more. Aginnovation is currently evaluating how long the systemic marker effects will last within different species. Presently, fluorescence lasts into the early stages of crop development. Aginnovation has only worked with vegetables, but plans to extend the technology into corn, cotton and soybeans.
Robotics is already utilized each day by growers. Agriculture has gone from rudimentary planters to sophisticated GPS planters that monitor every seed going into the ground -- all based upon robotics. Sophisticated spraying systems and seed treatment equipment are also all robotics-based applications. “Every day, more sophisticated technology is becoming a larger feature of agriculture. A progression of agriculture is to take a natural fit like robotics and expand it into the crop and into the ground,” Marks says. “Systemic marker technology is a unique application to drive efficiency in agriculture in ways that we haven’t thought about in the past. By doing so, we’re helping to reduce costs, improve efficiency, and boost yield.”