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Trevor Syme, Bolgart WA

Tackling weeds from the ground up

Trevor and Renae Syme are throwing everything they’ve got at revamping non-wetting sands and driving down weed numbers on their property at Bolgart, WA.

A few years ago they began an extensive liming and clay delving and spading program across 50 per cent of the 3500 ha cropping area to improve the water holding capacity of the natural non-wetting sands. With 75 per cent of the affected area now treated Trevor is looking forward to having this expensive but very beneficial operation behind him.

Treating the non-wetting soils has assisted with weed control through 40 per cent higher yielding crops, more even crop germination and better efficacy with the pre-emergent herbicides.

“Treating the non-wetting soils has assisted with weed control through 40 per cent higher yielding crops, more even crop germination and better efficacy with the pre-emergent herbicides,” says Trevor. “It has also enabled us to grow canola in paddocks that were previously not an option and crops seem to finish better and are less prone to frosting.”

They have also achieved good results building soil organic matter with brown manured cereal rye crops. Trevor has trialled summer crop brown manuring too but the results over three seasons were unreliable and he has decided to look for other options to reduce evaporation over summer and reduce the need for summer weed control.

The Symes’ farming system is 100 per cent controlled traffic and stubble retention with a long winter crop rotation of lupins, wheat, canola, wheat, barley, with brown manured cereal rye grown on the soils not suited to canola.

Information on the summer fallow spray program

The summer fallow spray program involves 2,4-D ester, triclopyr and glyphosate to control melons, caltrop, fleabane, sowthistle and volunteer cereals. For the last 5–6 years Trevor has applied a double knock of glyphosate followed with paraquat in preparation for sowing. “We try hard to get the timing right and target the right size weeds with the double knock,” he says. “We also avoid mixing a pre-emergent in with the paraquat because the aim is to get the paraquat on weed leaves using a high water rate and fine droplet size, whereas the aim with the pre-emergent is to achieve even coverage of the soil. Doing the pre-emergent spray separately costs us more but I believe it is worth using the right boom set up for the two jobs.”

“Rotating crops and herbicide modes of action, and using the double knock tactic, are critical to our weed management program,” he says. “RR canola, Clearfield barley and lupins all have a fit in the crop rotation and allow us to rotate herbicides effectively. The imi-tolerant barley has enabled quite effective control of brome grass and we croptop the canola with glyphosate.In the lupins we are using a pre-emergent propyzamide application followed with clethodim in-crop and finish with a croptopping spray of paraquat.”

Trevor is finding that weed control in the lupin phase is more critical than it used to be, but the value of lupins in boosting yields in the following wheat crop motivates him to look after the lupin crops, plant into clean paddocks and do everything he can to keep weed numbers low.

The Symes have had good success with high biomass canola on sandy soils where multiple germinations of wild radish are the norm. They usually plan their crop and herbicide program with their agronomist at the end of September and then revise it in February or March.

Trevor is going away from the current move toward narrow row spacing and disc seeders. “We are changing back from a disc seeder at 305 mm spacing to tines on 381 mm with a split boot to sow cereals in paired rows and canola and lupin in single rows,” he says. “We are working on the idea that less rows equals less disturbance equals less weeds in a controlled traffic system. The slightly wider row spacing also makes it easier to handle the stubble load accumulated over several years and allows us to inter-row sow.”

He has found that high tillering wheat varieties, such as Magenta, offer an alternative way to increase crop competition through additional shading of the inter-row.

In the 2015 harvest the Symes added a chaff deck to their weed control progam, directing all the chaff, and weed seeds, into the harvester wheel tracks. Trevor harvests weedy paddocks first to maximise the value of harvest weed seed control and has found the chaff deck easy to use and results in relatively few weeds surviving in the tramlines.

The biggest benefit of the chaff deck is that weed seeds are collected across the whole farm every year, and concentrated in the inhospitable tramlines.

“The biggest benefit is that we can collect weed seed across the whole farm every year where previously we have only really been able to do narrow windrow burning in the canola phase. Now at harvest the whole job is done, with no need to return to burn.”

“It is great to know where the weeds are and they are dumped on a hard, inhospitable surface,” he says. “Any escapes are easily collected at the next harvest. We also have a back-up plan to use a shielded sprayer to weeds in the tramlines, but we really want to avoid using this option.”

“In fields with high weed numbers in the tramlines we have tried simply driving a tractor, without any implement, along every tramline to achieve a crimp-rolling effect. This seems to have been a cost-effective way to stop seed set in weedy tramlines.”

In fields with high weed numbers in the tramlines Trevor has tried simply driving a tractor, without any implement, along every tramline to achieve a crimp-rolling effect (right).

Annual ryegrass, wild radish and brome grass are the main weed challenges on the Symes’ property. Trevor has done some herbicide resistance testing but generally takes the approach that all weeds present are likely to have some level of resistance. “The key is to keep weed numbers low so we take care to spray when weeds are small and avoid frost windows and high temperatures when the sprays are less effective,” he says. “We also use quite high water rates – 80 L/ha for most post-emergent herbicides and 120 L/ha for pre-emergent herbicides and paraquat – and have two sprayers so we can cover as much ground as possible when the conditions are right.”

“Fencelines and fire breaks are a weak point in our farming system as a source of glyphosate resistant weeds,” he says. “We have removed as many fences as possible, now that we don’t run any livestock, and are actively looking for an alternative herbicide that is not used in crop to manage weeds on the firebreaks.”

Trevor takes considerable care when choosing seed production paddocks, ensuring weed numbers are low to start with and then treating the paddock as a nursery. He harvests the seed crops early and cleans the seed prior to planting.

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Ask an Expert

Can pulse cover crops tackle multi-resistant ryegrass in irrigated systems?

The best weed control comes from tactics that also bring other benefits to a farming system.
Greg Sefton, principal agronomist with Sefton Agronomics in the Riverina, says multi-resistant annual ryegrass is becoming a major problem in irrigated systems.
Greg Sefton, principal agronomist with Sefton Agronomics in the Riverina, says legume cover cropping is providing effective control of multi-resistant annual ryegrass in irrigated systems.
“Herbicide resistance can move easily through irrigation areas, particularly when the control methods used on the supply channels are limited to just a few herbicides,” he says. “The ryegrass here is generally accepted to have resistance to glyphosate (Group 9 [M]), Group 1 [A] such as clethodim, Group 2 [B] and Group 3 [D], such as trifluralin. Growers are now relying heavily on Group 15 [K] products such as Sakura, and doing their best to rotate out of the problem.”
To regain control, Greg is working with growers to incorporate a multi-purpose fallow crop such as field pea into the system as a winter fallow clean with the added benefit of contributing biological nitrogen into the soil ahead of planting rice or wheat. 
Earlier maturing varieties of field pea provide better weed control options than Kaspa field pea, chickpea and lupin, all of which generally mature later, sometimes after the target weeds have set seed.
“A competitive pulse crop terminated at maximum biomass is an excellent way to reduce weed seed set,” says Greg. “It is a cultural control that also enables the use of some herbicides that are rarely used in our system. Combining the herbicide and cultural methods in the WeedSmart Big 6 is an effective way to keep our cropping options open and to maximise the value of applied water.”

What is the best fit for the legume crop as a winter clean?
In brief: In the Riverina, the optimal place in the rotation is ahead of rice.
The details: Fields selected for rice production are usually bare fallowed for the preceding winter. The aim of the fallow is to control weeds and conserve soil moisture.
Some growers are having success with field pea sown in May as a winter cover crop then terminated for silage or as a brown manure in early September. This fits well with preventing seed set in annual ryegrass, including late germinating plants.
Field pea is a competitive legume and can suppress weed germination and growth when planted in the most competitive configuration possible with minimal soil disturbance and no gaps.
A knockdown treatment of glyphosate (Group 9 [M]), clopyralid (Group 4 [I]) and carfentrazone (Group G [14]) is applied at planting then a mix of pendimethalin (Group 3 [D]), clomazone (Group 13 [Q]) and paraquat (Group 22 [L]) is applied after an irrigation flush to initiate rice germination and prior to rice germination to knockdown both newly emerged barnyard grass (BYG) and persisting ryegrass. This provides a double knock on ryegrass whilst applying a pre-emergent herbicide for barnyard grass in the rice phase.
When implemented once every 4 or 5 years, with a diverse rotation of winter and summer crops in-between, growers can keep a lid on herbicide resistant annual ryegrass populations. 
Field pea is a competitive legume crop that can reduce annual ryegrass germination in the paddock and halt encroachment from the crop borders.
How do you manage weeds on the non-crop areas?
In brief: The same herbicide mix is applied to the whole paddock, including the weeds growing in the check banks.
The details: Weed seed, often carrying herbicide resistance genes, travels easily through irrigation systems and can colonise non-crop areas. Seed from these plants readily infests the cropping areas if not controlled effectively. The control measures used on non-crop zones are often limited to herbicide tactics, so it is important to make sure the herbicide is applied to maximum effect to prevent seed set.
Farm hygiene and physical removal of isolated weeds will also have a positive impact on weed seed production. 
What farming system benefits come with growing a legume cover crop?
In brief: A legume crop grown for biomass rather than grain can improved soil tilth and reduce crusting on some sodic soils. This practice also allows better soil nutrition management and keeps the grower’s options open if the water allocation situation changes.
The details: The field pea crop will fix atmospheric nitrogen and this allows the grower to use 100 to 150 kg/ha less urea to grow the following rice crop without any yield penalty. If there is insufficient irrigation water available for a rice crop, then the fixed nitrogen is still available for a winter crop of canola or wheat.
The phosphorus fertiliser required for rice can be applied when the field pea crop is planted, giving the phosphorus time to become more available in the soil and ready for uptake when the rice is planted.
Field pea is quite drought tolerant, so if irrigation water is not available for rice, the field pea can be grown through to harvest the grain and will usually yield 0.7 t/ha, which can be more profitable than, say, a 1 t/ha drought-affected wheat crop.
Building an integrated farming system based on methods that have multiple benefits is fundamental to staying ahead of weed pressure.
Practical tips for growing field peas as a brown manure crop
Pulses to attack weeds on many fronts

Webinars

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Considerations for pre-emergent herbicides with dry sowing

In this webinar, we focus on what factors influence the residual control of weeds by pre-emergent herbicides with a focus on Trifluralin, Sakura and new-to-market herbicides.
Chris Davey, YPAG and WeedSmart Extension Agronomist and Mark Congreve, ICAN Senior Agronomist, assessed the sowing issues in South Australia and discussed strategies on using pre-emergents.
Factors covered include:

Soil type/texture
Rainfall forecast (after application)
Characteristics of the herbicide
Characteristics of the crop
Sowing time (tine vs disc) – sowing depth, speed, soil throw, stubble
Resistance status

GRDC Spray Application Manual
This Spray Application GrowNotes™ manual provides information on how various spraying systems and components work, along with those factors that the operator should consider to ensure the sprayer is operating to its full potential.
This manual focuses on issues that will assist in maintaining the accuracy of the sprayer output while improving the efficiency and safety of spraying operations. It contains many useful tips for your spray operations.

Videos

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Video
Video

Rod Birch on how the Big 6 is keeping weeds at bay at Catalina Farms

Catalina Farms is approximately 13,000 ha of 100% cropping, with 65% wheat, with the other 35% comprising of 20% canola and 15% lupins. The longterm rainfall is about 330ml per year and around 250-280ml of growing season rainfall.
Taking on a new property usually has its challenges, but there can be upsides too. Some of the challenges at Koobabbie were related to the fact it had been a livestock property and cropping machinery had never having been run through it. However, Rod explained that they have had some great news about the herbicides they are able to use.
Through the University of Western Australia’s resistance testing service, run by Dr Roberto Busi at AHRI, they found out some older chemistries were still effective, which was a pleasant surprise. Daniel Birch explains below in the Regional Update Podcast what they found out and how they used this information in their planning.

Video breakdown

1:10 Crop rotations – Rod’s favourite rotation is Lupins – wheat – canola – wheat. It provides a lot of diversity for Modes of Action, as well as allows for nitrogen to go back into the soil through the lupin phase.
2:10 Crop Competition – the Birches are big fans of crop competition and it’s an essential part of their approach to controlling weeds.
3:00 Double knock – conditions haven’t been suitable for a double knock since 2016, but when the opportunity arises, it’s an important tool.
4:21 Mix and rotate herbicides – the crop rotations used at Catalina allow for really diverse chemical groups to be used, which is a great tactic to keep resistance at bay.
5:52 Stopping weed seed set – the Birches are trying to eliminate as many weeds in the crop as possible. Crop topping is a tool that they employ, as well as late spraying where necessary.
6:49 Harvest weed seed control – seed destruction is on the horizon at Catalina, but logistically has been a bit tricky.
7:21 Acquiring Koobabbie – it has been exciting for the Birches to be able to introduce more diverse rotations. They’ve been able to use Modes of Action which have never been used before.
9:48 Soil amelioration  – liming has been a really beneficial tool for Catalina Farms. They also put out pot ash and gypsum. Deep ripping has also been a great tool to remove the compaction layer.
11:29 Big 6 benefits  – controlling weeds is such an important strategy at Catalina Farms. Rod Birch said “We’ll never have a ceasefire on the war on weeds!”.

 

Video
Video

WeedSmart Week Forum Day Videos

List of videos

Interviews with the Esperance Pioneers. Chair: Lisa Mayer, interviewing Neil Wandel & Theo Oorschot
Rotating buys you Time, mixing buys you shots
Efficacious use of the new pre-ems, Brent Pritchard
Delivering regionally focused research
Crop competition in wheat and canola, Hugh Beckie
Summer weed control
Strategies for control of ryegrass, marshmallow, fleabane, portulaca, Greg Warren
Farmer Experience
Rotations to stop seed set and preserve chemistry, Tom Longmire
Soil Amelioration, Tom Edwards
Crop competition: Reduced row spacing, higher seeding rates, east-west sowing, precision seed placement & competitive varieties, Theo Oorschot
Farmer Experience – Utilising crop competition strategies and the Big 6, Mic Fels
Weed control – farmer systems discussion panel – Chair: Peter Newman, with Mark Wandel and Laura Bennett
What’s next in spray technology? Andrew Messina
What’s next in spray technology 2? Guillaume Jourdain
Innovation Panel – Chair: Ben White, with Guillaume Jourdain, Andrew Messina
Stacking the Big 6 in farming systems in WA presented by Greg Condon, with Peter Newman

Video
Webinar

Considerations for pre-emergent herbicides with dry sowing

In this webinar, we focus on what factors influence the residual control of weeds by pre-emergent herbicides with a focus on Trifluralin, Sakura and new-to-market herbicides.
Chris Davey, YPAG and WeedSmart Extension Agronomist and Mark Congreve, ICAN Senior Agronomist, assessed the sowing issues in South Australia and discussed strategies on using pre-emergents.
Factors covered include:

Soil type/texture
Rainfall forecast (after application)
Characteristics of the herbicide
Characteristics of the crop
Sowing time (tine vs disc) – sowing depth, speed, soil throw, stubble
Resistance status

GRDC Spray Application Manual
This Spray Application GrowNotes™ manual provides information on how various spraying systems and components work, along with those factors that the operator should consider to ensure the sprayer is operating to its full potential.
This manual focuses on issues that will assist in maintaining the accuracy of the sprayer output while improving the efficiency and safety of spraying operations. It contains many useful tips for your spray operations.

Factsheets

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Fact Sheet

Stewardship First SprayBest Guide

The application of herbicides late in the season to prevent weeds setting seed or to desiccate crops must be carried out with caution and in line with herbicide label recommendations.
It is essential to check if these practices are acceptable to buyers, as in some situations markets have extremely low or even zero tolerance to some pesticide and herbicide residues.

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