Environment

Time-saving green tech kills those "blasted weeds" without chemicals

Time-saving green tech kills t...
The abrasive weeding rig used in the experiments
The abrasive weeding rig used in the experiments
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The abrasive weeding rig used in the experiments
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The abrasive weeding rig used in the experiments

Although there are various other types of eco-friendly weed control, organic farm workers often end up doing what most of us do in our backyard gardens – bending down and yanking weeds out by hand. Thanks to the relatively new process of "abrasive weeding," however, that may not always be necessary. As an added benefit, crops could be fertilized and weeded in one step.

First introduced a few years ago, abrasive weeding involves blasting weed seedlings with organic grit, shot out of an air compressor at supersonic speeds. In field tests recently conducted by a team led by University of Illinois agroecologist Samuel Wortman, it was discovered just how effective the practice can be.

The process works best on transplanted crops – in which the "good" plants are bigger and more mature than the weeds sprouting around them – and in conjunction with sheets of plastic mulch. As long as they're of a species in which the growing points are located above-ground, the weed seedlings are killed when blasted apart by the grit.

That grit can be made from almost any organic material, including nut shells, corn cobs or other agricultural waste. As noted by the Illinois team, however, fertilizers such as soybean meal could also be used. This would allow farmers to combine weeding and fertilizing in one pass, although "it is still unknown whether the fertilizer would be available for plant uptake within critical windows."

In the Illinois trials, tomato and pepper plants did sustain some superficial collateral damage, but it didn't affect their marketable fruit yield. That yield was along the same lines as is achieved when weeding by hand, and was 33 to 44 percent higher than that of non-weeded control crops.

The grit was applied using a sand blaster connected to an air compressor, pulled down rows of plants by a walk-behind tractor – it can be seen in use below. Wortman and his team, however, have since developed a dedicated device which is now undergoing testing.

A paper on the research was recently published in the journal Crop Protection.

Source: University of Illinois

Weed blasting in tomato plasticulture

6 comments
Bob Stuart
Let's not apply the same inhibitor to all plants like another dumb chemical. A simple coloured collar around each crop stem could identify it to a robot, which could then precision-blast any other nascent greenery. Lasers also work - you only need to overheat the cells in one section, and weeds die.
DebbieLong
Funny how people think "weeds" are bad. Do this - Google: 10 surprising health benefits of eating dandelion “weeds”
CliffG
Debbie, a tomato plant is a weed if you are growing cucumbers. If your intent is to grow dandelion, then they are no longer weeds. By the way, this grit-blasting approach seems the epitome of crude solutions. With present machine vision and robotic actuation technologies, weeding can be fast, precise, and without collateral damage.
science ninja
time to end the poisoners reign.
StWils
There is another significant problem with this device and that is that compressed air is actually a fairly expensive form of energy. What is needed is something more like a roomba vacuum that can quietly be set to travel a field and selectively "Chew" through unwanted plant stems. No need to obliterate the plant, just damage it enough to stop competition with the intended crop. Something with a small scale weed whacker like head just big enough damage a stem and mounted on an arm would do the trick at far more attractive price. The 3D printers that are widely available and the wide array of resins should permit rapid prototyping at a good cost.
Don Duncan
Three solutions for increased crop production: 1. Close companion planting. Aggressive plants that shade out weeds, but don't adversely affect production. 2. Weaken weeds enough to give the desired plant a head start. 3. Treat the seeds/roots of the crop so it is energized by enzymes.