Slowly finding its spot
Precise applications using optically guided sprayers to apply chemicals to a patch size less than 25cm, and as small as 4-6cm, offer the potential to cut chemical costs, reduce phytotoxicity and may play a role in protecting active ingredients against future legislation, according to a report in Pro-Operator magazine.
While initially promoted as a means to save chemical costs, recent research shows the gains from reduced phytotoxicity from selective herbicides produce much higher returns.
Syngenta trials in Germany tested spot spraying sugar beet from a ‘prescription map’ from images scanned by drone – rather than spot spraying in real time. This technique generated huge gains with the chemical savings of up to €45/ha (£38/ha), but these were dwarfed by up to a €300/ha (£250/ha) benefit from a 10% increase in sugar yield, due to reduced phytotoxicity compared with blanket spraying.
Weed Wizard
Developed and manufactured by Techneat Engineering and software specialist Tillett and Hague Technology, Weed Wizard is aimed at contractors and growers of onions, leeks and carrots.
It is designed to differentiate the weeds from the plants and target them accurately with selective herbicides.
“A blanket application to onions takes the wax off the leaves, so you can’t apply any other products for two weeks without damaging them. After spot spraying, you can go in with other applications as required,” explains product specialist James Everitt.
Using high-speed, narrow jet nozzles spaced every 100mm across the full width of the boom, Weed Wizard’s three-camera system identifies and tracks weeds as they come into view, applying spray onto each weed as it passes under the nozzle.
Weed Wizard is configured for a three-bed system with a working width of 1.83m. It now uses Techneat’s own design of narrow 15° nozzles for better chemical-to-weed contact. Recent updates include the ability to adjust the boom height, improved weed recognition, updated software as well as changes to the side-shift system.
Spot on for onions
Martin & Sons of March, Cambridgeshire purchased a Weed Wizard to use on 34ha of onions, part of a rotation that includes cereals, potatoes and sugar beet.
“We make three applications during the growing season with the Weed Wizard, and by targeting only the weeds we avoid knocking back the crop growth. This also helps the onions mature more quickly,” says Andrew Martin.
“The weeds need to be big enough for the cameras to pick up – spot spraying is best for targeting larger weeds rather than a mat of small weeds, so an overall spray is applied soon after planting to gain the initial control,” he adds.
The software can be set to put the onion rows in an ‘exclusion zone’ – used at the early stage of crop growth – or to limit the target size to hit the weeds in a small area around it.
Andrew says initially it is difficult to exactly calculate the total spray volume required, but this becomes clear after a few applications. “Savings on chemicals are significant because we are only spraying 1.5%-2% of the field now,” he comments.
Yield benefits are more difficult to quantify without specific trials, but he suggests that the stronger onion plants are also more resistant to disease.
“It’s the right way to go, a grant helped with purchase but with the significant investment required, it’s going to be most suited to high value crops. We would consider using the Weed Wizard on our sugar beet when the algorithms are ready for that crop,” he says.
Read the full story here on the EiOperator website, or download a copy of the article.
About the author
Mark Sanderson
Director, TOP PR Ltd.