New Weed Fighting Methods
Farmers first used cultivation to mechanically kill weeds. Hand hoeing, pulling weeds, then horse and tractor driven cultivators. Then they started using chemicals
starting with 2-4D to chemically kill broad leaf weeds. New chemicals were developed and then came along glyphosate (Roundup) which became the most popular herbicide, especially when the glyphosate resistant gene was introduced into many crops. But like all new innovations, sooner or later they are replaced due to limitations.
Cultivation disturbed the soil and took a lot of fuel and time. Every time you disturb soil, you replant weed seed and you lose carbon in the form of soil organic matter. There can be as many as several hundred thousand weed seeds per square yard in soil. This weed seed can remain viable for a few years, a decade, or even longer. Weed seed with thicker coats and buried deep with tillage survive longer than those left on the soil surface with no-till. On the chemical herbicides, herbicide resistant weeds are now a problem and herbicides may be toxic to beneficial plants, animals, and humans.
New innovations in fighting weeds are now becoming a reality. First, electro-shocking uses onboard generators to pass electricity through plants. The electricity destroys chlorophyll and cell walls in the vascular system, causing plants to die from desiccation, drying them out within hours. On board sensors can distinguish between weeds and a good crop. It is fast, moving across the field 3X faster than cultivation. A new product called Hybrid Herbicide is sometimes used to enhance electrocution of weeds. It is a blend of humic acid, sugar, biochar, and oil esters which allows electrons to penetrate the plant better for a more complete kill. It is sprayed on the plant right before electricity passes through the plant.
Lasers attached to computers using AI can recognize weeds and zap them as the machine moves across the field. Often, they are put on robotic weed zappers called Laser Weeders which can operate within 1 millimeter (a hair’s width) of beneficial crops. Vegetable growers are using this innovation. It may also be used to fight invasive weeds like Palmer amaranth and marestail in the Midwest. The payback is about 1 to 3 years due to reduced hand weeding and reduced herbicide costs.
Farmers now can also use “Blue Light” which a machine attached to their combine that hits weed seed with Directed Energy (DE) light waves. Called the Weed Seed Destroyer, the machine hits weed seed as it is being passed through the combine with a LED Blue light that inactivates weed seed germination. It take 4 seconds and can reduce weed seed germination by 97% to 99%. The same technology can be used to increase crop seed germination by using 50% LED light and some of the same technology is being used to kill cover crops as a burn down.
Another way that technology is helping farmers reduce their reliance on chemical herbicides is through AI and onboard sensors. The sensors and AI detect weeds growing with the crop and spray just the weeds, reducing chemical application rates. This variable rate technology can reduce herbicide usage up to 87% to 94%. Some systems report a 7% improvement in weed control over a typical broadcast spray. Why? Because the spot spraying hits the weeds more intensely, even at different angles, using smart computer driven AI systems. Multiple nozzles, different angles, and even different sprays can be controlled with the computer to spray troublesome weeds to kill them effectively. Some of these rigs can even be operated at night.
Small mechanical robotic weed eaters are also being developed. These self-propelled robots use spinning blades and are used in corn, wide row soybeans, and cotton. They operate at about 1 acre per hour. Farmers can rent the machine and usually 10 machines operate at the same time. They run on batteries for 4-8 hours and a service man comes with the rental fee. It saves the farmer money by not having to buy the machine and gives the farmer flexibility. The robots weigh about 350 pounds each and are guided by Lidar (topography), RTK satellite signals, and AI. Its much cheaper than herbicides in some cases, depending on weed intensity. These machines can be used multiple ways including preplant, post plant, and after a burn down chemical treatment, offering the farmer a lot of flexibility.
On a final note, a little ethylene enhances weed seed and crop seed germination. Spraying with
ethylene can get a majority of the weeds to germinate and then they can mostly be terminated all
at once. Source for this article: No-till Farmer, Dan Crummett.