New technology takes weed control back to the future… herbicide use may decline (part one)

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The relentless march of agricultural technology affects every sector of the industry sooner or later; sometimes it may even be a “back to the future” approach. So it seems with the explosion of research into new mechanical forms of weed control. That research may have a profound effect on the continuing march of herbicide use in commercial field crop agriculture and horticulture.
Seventy years ago, the only practical way to deal with weeds was with specific tillage or hoeing by hand, but both methods had their shortcomings. These were largely resolved with the introduction of commercial large-scale herbicide spraying. Genetically modified (GM) plants were developed to accommodate herbicides and pesticides. That led to the establishment of world-wide ag chemical industries involving billions in annual sales. Were it not for the advancement in chemical control of weeds and pests, food plant production would have been dramatically less. It would be fair to say that without the contribution of ag chemicals, food would have been more expensive and even scarce for much of the global population. Be that as it may the future use of ag chemicals may now be facing a new challenge from high tech mechanical weed control (MWC) methods.
MWC has always been around, with various tractor-mounted devices being used on row crops for years. Researchers even invented a process that used flames to incinerate weeds in some crops, but effectiveness and timing were always of concern. Ongoing research advancements in MWC technologies continued to be made, particularly in the last ten years. Here are few big leaps.
Probably the biggest advancement has been in computer imaging technology that is able to instantly identify weed species – it is the common thread amongst all the new mechanical weeding developments. One development involves small to medium sized self-propelled robotic machines that can travel between rows as narrow as 15 inches using on-board sensors to identify target weed species. Depending on the device the robot then either plucks the weed, or destroys it with an electric charge, or sprays it with herbicide. It is precision weed control at its best and harkens back to the old days when a person with a hoe would identify the weed and hoe it accordingly. The difference is of course that a machine is much more efficient and precise than a human could ever be. Which new mechanical process prevails will depend on cost and efficacy. The electrical shock is appealing in that it kills the weed completely, root and all, and is unlikely to develop resistance. Plucking works, but it may leave intact roots that can regenerate, the herbicide approach works but resistance may eventually occur.
Ag machinery companies and even herbicide manufacturers are rushing into this new technology. If it becomes successful, it will present a very serious challenge to existing herbicide marketing. Initially it will be used in high-value crops like potatoes, sugar beets and in the horticulture sectors. Corn growers will probably be the biggest market for the new technology, bringing into question the future of GM corn. If MWC becomes cheaper and more practical it is expected that the use of glyphosate will crash. One can see why ag chemical companies may be getting rather concerned about their future.
One can envision fleets of autonomous MWC machines working large fields, vineyards and orchards. If done enough and at early stages of weed growth there is the potential of significantly reducing levels of weed infestation on a long-term basis. With MWC and electronic plant identification, no weed would be immune to destruction. Weeds that resist chemical control or require complex formulations would not survive an electrical shock or plucking. The rush to come up with a cost-efficient machine is the present matter-at-hand. Early prototypes are as expected, costly and not without glitches. But with the investment of big ag industry players into this new technology one surmises that its potential is being recognized.
Even if MWC does become the norm, the use of herbicides and pesticides will not be over. Diseases, fungus, parasites and a host of other pests will still require chemical controls. What may change is their application methods – land-based robots will be of value along with the increasing use of drones. Those aerial devices are already being used to scout for disease and parasites in high-value crops. It would seem that the future holds much more use of robotics in agricultural applications. More next time. Will Verboven is an ag opinion writer and agriculture policy consultant. willverboven@hotmail.com