Herbicide resistance is a growing area of concern in Australian farming systems. Weed management is a complex issue, trying to maintain a balance between resistance, control achieved and expenses can be challenging.
BCG is carrying out research and extension around the adoption and agronomic use of shielded sprayers in the Wimmera and Mallee. This includes a trial which aims to provide a breakdown of shielded sprayer effectiveness and economics of use in a problem ryegrass paddock. The project is being enabled through a fellowship funded by the Hugh D. T. Williamson Foundation.
Kinnabulla grower Lincoln Lehmann came up with a “crazy idea” several years back while facing the challenge of brome grass control and getting frustrated with group B products.
“It was getting to a stage where you’d base your rotation around weed control rather than the most profitable option,” Mr Lehmann explained.
Mr Lehmann runs a 2300ha continuous cropping property with his parents and grows wheat, barley, canola, field peas and lentils.
He found that brome grass was starting to become a problem and started looking at a novel way to tackle it. After a lot of time testing smaller versions behind the motorbike and around a month in the workshop, he came up with the first version of his shielded sprayer.
“I was shocked with how well it worked.”
The first year he mostly targeted problem patches, but since then he’s done whole paddocks across the farm and in the last few years estimates he’s covered between 15-30% of the property each year.
“I did quite a bit last year, but I’m starting to ease off as it actually seems like the farm is quite clean. I’ve got a couple of new blocks with some ryegrass issues so I’ll be trying to work them down a bit.”
Mr Lehmann only uses his shielded sprayer in cereals as they are able to guide the shields between the crop rows.
Varieties with erect growth habits work best; it works well in wheat and upright barley varieties like Spartacus and Hindmarsh. He has predominately used paraquat, but finds glyphosate to work well too.
Timing is the most important factor in reducing crop damage.
“If you go in too early you start hitting lower leaves in the crop. One year I used glyphosate too early on about 5ha and nearly wiped out the crop. You need to wait for the lower leaves to die off.”
Generally yield is unaffected when it’s used “in the right crop at the right time.”
He’s made a few modifications since the first model with some tips from Swan Hill grower Leigh Bryan who similarly designed his own shielded sprayer.
“The first version was more rigid, it jumped around a fair bit. Now the shields do most of the work, they follow the crop rows as you go along.”
Overall Linc is impressed with how it has improved weed control on the farm.
“The farm is going in a good direction and not getting out of control with brome grass.”
“There was a huge sense of achievement actually. It’s one of the most satisfying things I’ve done on the farm thus far. I think just seeing how well it can work, and that it does actually work.”
“It’s another tool. The more tools you have to control weeds the better off your farm will be.”
BCG will be extending information and results from this project in the coming months. For more contact the BCG office.
This article was published in the Stock and Land, August 10.
This article was produced in conjunction with the Hugh Williamson Scholarship.
