Weed management is a long term battle for Coorow district producer, Rod Birch as he farms 5000 hectares of country in the central Western Australian grain belt.
Together with wife Shelley, Mr Birch made the decision 15 years ago to stop running livestock and concentrate on growing cereals, oilseed and pulse crops.
The couple has always been at the forefront of technology but the move to cropping-only has created its challenges with weeds.
“In terms of moisture, the no-till and moisture conservation farming equipment gave us a great opportunity to keep a lid on as much moisture as we can to convert into grain so we adopted that in the mid 1990s,” Mr Birch said.
“We went away from any full cultivation to knife point seeding and one pass operations and in most cases full stubble retention.”
The Birches introduced GPS and auto steer, auto boom shutoff and other features and have been yield mapping since 1996 but there has been one growing problem – variable plant-available moisture.
“The biggest challenge we have in dryland cropping is moisture and that is probably the main factor that is out of our hands,” Mr Birch said.
“We’re always looking at how we deal with moisture and what competitors we have for that moisture.
“I make weed control a priority.”
Since the Coorow producer went across to total cropping, the weeds in his district have developed herbicide resistance to most of the chemical groups.
“The weeds have adapted to minimum tillage, and our reliance on chemicals and herbicide,” Mr Birch said.
“This has made us look at the knowledge and science we had available in terms of chemical groups and learning as much as we could about herbicides and having no livestock in the system.
“We made sure we adopted a real rotational approach to our cropping system which would give us opportunities to use different chemical groups and rotate them and provide us as much diversity in the system.”
Mr Birch has developed a strong rotation to keep that diversity on the property, in the absence of sheep.
This approach has seen him look for more tools to management herbicide resistance in all the major weeds.
“We keep our eyes and ears open on what was happening in other areas already in a monoculture and there were some issues that came up very quickly in terms of weeds resistant to different herbicides groups,” Mr Birch said.
“What we did was took up integrated weed management fairly early and we learnt to stick to a fairly solid plan and make sure we could maximise our opportunities there.
“That meant growing different crop types and sticking to rotations where the same crops were more or less popular due to price or due to the ability to grow them in an easier manner.”
The Birch family settled into an easy rotation of wheat and lupins but it started to create challenges with weed management.
“When it became obvious the rotation was not going to last, what we had to do was spread our cropping and introduce canola into the rotation,” Mr Birch said.
“Our typical rotation would be a lupin crop up front to get that legume foundation established and then we would go wheat, then a canola to enable us to use different herbicide options again.
“In recent times we have been able to grow Roundup ready canola so that gives us more diversity again but we will still be growing TT varieties and then another wheat crop.”
In between crops they are also using different tools for weeds management, which involves trailing behind the header and then burning the residue in those trails.
“We’re on a mission to try and eliminate weed seed set at every opportunity we get,” Mr Birch said.
“I also deep rip our better sand plain soil following the lupin crop so we get a good busting up of the hardpans we created, followed by the fibrous root crops like wheat and canola.
“It gives us a chance to get in and spray some weeds out of crops.”
The family has been involved with a Grains Research and Development Corporation (GRDC) project on their property for the last eight seasons with Peter Newman, Department of Agriculture and Food WA (DAFWA) managing this project.
A number of focus paddocks have been set up on the property to provide data on the weed management system.
“What we’ve found is this coincided with us using all the possible opportunities to deplete ryegrass seed numbers and radish seed numbers through header seed trailing and burning header trails, rather than spreading weeds behind the header,” Mr Birch said.
“We try and capture and destroy weed seeds with both chemical and non chemical means and that project has shown that where we started focus paddocks, with very high weed numbers, we’ve seen a great reduction in those numbers.
“That has been purely through the applied science and through having great appreciation in how to eliminate our competition, stick with the rules and don’t leave any stone unturned in terms of allowing those weed numbers to increase again.”
Mr Birch is not one to rest in his quest to maintain the upper hand on weed control and he’s always looking for new ways to manage herbicide resistance.
“We don’t want to destroy the integrity of our system but at the same time there are always slightly new cultural improvements and new opportunities coming along in terms of weed seed destruction, at the back of the harvesting machinery and we are always looking at the development of that,” Mr Birch said.
“In terms of our own farm hygiene and all around the farm we pay a high level of attention to detail in making sure we don’t have nurseries of weeds which can be picked up in our other operations and spread around the place.
“I think what we do is make sure we operate at a very high level given, that it is very easy to be average but to give it that extra level of commitment to get that extra ten or 20pc to top off the job and make sure it is done right.”
For more information, visit www.grdc.com.au.
