Jason and Stacey Coleman, Temora NSW
Flexible and responsive weed management
South of Temora in NSW, the Coleman family run a 6000-ha cropping enterprise on several farms within 30 km of the home farm. Jason is the third generation of the Coleman family to farm ‘Moascar’, along with his wife Stacey, his parents Peter and Lyn, and three permanent staff members.
Having a large cropping program to manage, Jason keeps their crop rotation simple and concentrates on optimising their productivity and profitability. He is constantly reassessing their current practices and adapting their farming methods to improve their long-term sustainability. The Colemans are active members of the Temora Ag Bureau, a local grower group, and the family has hosted various FarmLink trials on the property over many years. They also do their own paddock trials to assess the value of new ideas or products.
“After attending WeedSmart Week in 2023, I decided to go back to 250 mm row spacing after sowing on wider spacing for the last 15 years. The evidence is clear that the narrower row spacing really makes a tangible difference to in-crop weed pressure,” says Jason.
“Our other recent priorities have centred on increasing the competitiveness of our crops, using desiccation as a strategic weed control tool, keeping our powerlines, fence lines, firebreaks, and beneath our paddock trees weed-free, and monitoring for weeds more often – recording size, location and numbers, across the farms.”
The main weeds on the farm are annual ryegrass, wild oats, fleabane, sowthistle and Jersey cudweed. The Colemans are contending with patches of glyphosate-resistant annual ryegrass and long-term resistance to fop herbicides.
With valued input from their agronomist, Craig Warren from Nutrien Ag Solutions in Temora, the Colemans follow a herbicide program that includes using herbicide mix and rotate strategies, optimising spray efficacy and managing stubble to broaden their herbicide options.
By using all the tactics in the WeedSmart Big 6 strategy, the Colemans are keeping weed numbers low and reducing the impact of herbicide resistance on their farming enterprise.
WeedSmart Big 6 in action
The Coleman’s farms have predominantly red loam and red-brown clay soils, which are well-suited to a cropping program of 40 per cent canola and 60 per cent wheat. A 5-year rotation of canola, wheat, canola, wheat, wheat, generally works very well.
If a paddock is getting weedy, they will often plant a brown manure crop instead of the final wheat crop, to run down the weed seedbank. In the past they have used field pea for brown manuring but now prefer sowing vetch on the weedy section, or sometimes the whole paddock, and then spraying out the area for maximum weed control.
“We have had five good autumns in a row here that have allowed us to apply a pre-sowing double knock across the farms each year,” says Jason. “This has driven down our weed seed bank and reduced the need for brown manure treatments since 2020.”
They grow triazine-tolerant (TT) and Clearfield (Intervix / imi-tolerant) canola varieties, and three wheat varieties with different planting windows.
The family began phasing out their sheep enterprise around 2009 and implemented a controlled traffic farming system with inter-row sowing.
The Colemans grow hybrid canola varieties for their high yield and strong weed competition. Having a highly competitive crop in each paddock every second year is a very effective, non-herbicide tactic that provides paddock-wide weed control.
The early-sown wheat variety is always more competitive, so Jason usually targets weedier paddocks for early sowing. Varying the sowing date for a paddock each year helps disrupt any shifts in weed seed dormancy, and keeping at the front end of the planting window for each variety maximises early vigour to reduce weed germination. Seeding usually takes about three weeks, so having early, mid and late-season varieties helps to get everything planted on time and manage frost risk.
Having noticed areas around the farm that consistently grew poorer crops and allowed more ryegrass to grow, Jason has been grid sampling the farms over the last several years to identify areas of low soil pH. The red loam and red-brown clay soils tend to be slightly acidic at depth, in the pH range of 4.5 to 5.
To address this soil constraint, they have applied lime at variable rates according to acidity levels across the farms and incorporated it with a Horsch Tiger cultivator. They plan to use surface applications to maintain the soil pH around 6 to promote even crop growth and reduce the opportunities for weedy patches to establish.
Jason is also spreading, and now incorporating, chicken manure in some paddocks to build soil organic matter and increase crop biomass, with a spin-off benefit of increasing the crop’s competitive advantage in areas of lower fertility. The Colemans use a quad-tracked Steiger tractor for seeding, spreading ameliorants, and hauling the chaser bin at harvest.
They previously retained all their crop stubble as a valuable part of their livestock enterprise. Since they phased out the sheep and introduced the controlled traffic farming system, they have found that the benefits of stubble burning following high-yielding seasons outweigh the disadvantages.
“In the last 4 or 5 years, we have had several big crops in a row, which has caused stubble management issues at seeding,” says Jason. “Under these circumstances, we burn most of the wheat stubble and mulch the canola stubble.”
“Burning the wheat stubble provides a weed control benefit similar to narrow windrow burning, which we have practised for over 20 years,” he says. “We use harrows or Kelly Chains to mulch the canola stubble. Reducing the stubble load has made it easier to inter-row sow and gives the pre-emergent herbicides a greater chance of success.”
The Coleman’s CTF system was set up around 2009 on 3 m wheeltrack spacing to run their 36 m sprayer and fertiliser spreader, 18 m seeder and 12 m header/windrower/lime spreader. They own 95 per cent of their machinery, making it easier to get jobs done when the conditions suit best. The CTF layout has 80 per cent of the cropped area aligned for sowing east-west, which is known to provide an additive weed suppression benefit without compromising crop yield in southern cropping regions.
“In 2006, we changed from 230 mm spacing to 300 mm to make inter-row sowing easier in our controlled traffic system,”says Jason. “Now that we are reducing the stubble load, the tined seeder works well on 250 mm row spacing. We can use a broader range of pre-emergent herbicides and gain more crop competition benefits.”
The Colemans recently purchased a self-propelled Case Patriot 4350 sprayer with pulse width modulation (PWM) technology. This gives the operator more flexibility to adjust pressure without compromising ground speed and water rate. Turn compensation also helps avoid low-dose application around trees and power poles.
In 2020, they purchased a WeedIT boom to help them manage herbicide-resistant weeds in summer fallow. They use the double-knock tactic with a blanket spray of glyphosate followed by the WeedIT to apply paraquat with a Group 14 [G] spike 14 days later to control fleabane and any other survivor weeds. The WeedIT typically sprays 10 to 20 per cent of the paddock. Jason uses high water rates (up to 100 L/ha) in both the WeedIT and Patriot SP, particularly in autumn, to maximise the efficacy of the herbicides.
He also prioritises spraying soon after rain to treat fresh, healthy weeds, preferably when they are small, and avoids spraying in hot, dry, dusty or still conditions.
They are particular about keeping the ground under paddock trees, around power poles and along fence lines and firebreaks weed-free. For trees and power poles in the paddocks he uses a buggy and boom, and on fence lines and firebreaks he uses the tractor with a 3-m fence line boom to apply long-lasting (12+ months) residual herbicides.
Each farm has water points, with at least 50,000 litres of rainwater stored in tanks. Their chemical mixing truck travels with the sprayer to maximise spraying efficiencies.
The Colemans retain stubble over summer to conserve moisture, but if there is a heavy cereal stubble load, they burn before sowing to avoid blockages. Increasing sunlight on the soil surface also promotes early seedling vigour and crop growth. In canola, they mulch the stubble rather than burn it.
Having less stubble on the surface also means they can continue using trifluralin, which has been a valuable chemical in their program for a long time. There is also less interference from stubble on herbicide coverage, avoiding the potential of delivering low herbicide dosage to weeds, which can increase the risk of resistance.
For the last 20 years or so, the Colemans have been testing their wild oats and annual ryegrass populations for susceptibility to the key herbicides every few years. This has helped them to implement herbicide programs that extend the life of each molecule.
In recent years, Jason has started to monitor and check for weeds more routinely – noting the location of weedy patches on their farm map and taking action early.
“I am noting what worked, what didn’t work, and thinking about what to change next time,” he says. “We are keeping an eye on the weeds all the time.”
They use the double-knock tactic of glyphosate followed by paraquat plus a spike for their summer spraying and pre-sowing, where he applies glyphosate followed by a mix of pre-emergent herbicides plus paraquat.
They use Overwatch + trifluralin on Clearfield canola and propyzamide + trifluralin on TT canola. In wheat crops, they use Sakura pre-plant, or Mateno Complete applied post-planting at the second emerged leaf stage of the crop.
Lontrel is applied across all paddocks for fleabane control except in areas where Jason plans to plant a brown manure crop. In wheat, he uses a mix of Lontrel, Precept, Amine 625, Ally and MCPA for broadleaf weeds, and Atlantis and Axial for wild oat control.
If weed pressure starts to build up, the Colemans have found that a brown manure fallow is a very effective way to stop weed seed set and run down the weed seedbank.
“We have also grown vetch for hay, but this is not something we would do very often,” says Jason. “Brown manure is definitely our preferred option. It is most valuable in years with a dry autumn, so we have not done any brown manuring here in the last four or five years.”
Before phasing out their sheep enterprise in the early 2000s, the Colemans relied on grazing the crop stubble to stop weed seed set in summer. Now that the sheep are gone, Jason has implemented a regular summer spraying program, making it a priority to treat weeds before they grow large or become stressed.
He also uses desiccation and windrowing as harvest aids that help control weeds that are setting seed late in the cropping season. Their usual practice of windrowing the canola is generally sufficient to control the few weed escapes at the end of the season. As a result of the wet spring in 2023, there were more weed escapes than usual, so Jason took the opportunity to desiccate their canola crops before windrowing.
They are also prepared to spray out weedy patches in wheat crops as required, choosing to sacrifice small areas of the crop to reduce weed pressure for future years.
More recently, they have started desiccating their crop headlands and paddock corners to stop weeds encroaching from the borders.
The Colemans started harvest weed seed control using narrow windrow burning over 20 years ago to help manage herbicide-resistant annual ryegrass. As part of their harvest preparation, Jason assesses the weed burden in each paddock and checks for survivor weeds. These days, narrow windrow burning is only practised on high-weed-pressure blocks.
In high-yielding seasons, they usually do a blanket burn to reduce the stubble load and use tillage as a strategic tool in their weed control program. Burning is a cheap non-herbicide tactic that helps kill weed seeds at and near the soil surface and also reduces slugs. In lower-yielding years, they usually harvest low to the ground, leaving shorter standing stubble. The shorter stubble interferes less with herbicide applications and allows interrow sowing.
In paddocks where weeds are a concern in these lower yield seasons, Jason attaches the NWB chute to the harvester and implements a hot burn the following autumn to kill weed seeds collected at harvest.
“We own our harvesters, which gives us the flexibility to use the narrow windrow chute when we feel it’s necessary,” he says. “Ideally, we target problem paddocks early in the harvest period to maximise weed seed capture.”
Jason Coleman with his son Eddie at ‘Moascar’, Temora NSW. The Colemans use a quad-tracked Steiger tractor for seeding, spreading ameliorants, and hauling the chaser bin at harvest.
