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Making clean seed your business

In 1980 the Bach family of Toowoomba diversified their farming operation to include a commercial grain storage and handling facility. With a background in grain production the family knows what’s needed to provide an efficient and safe grain handling service for other farmers.

Not only do they know the importance of cleaning and grading grain to bring it ‘up to spec’, they also understand the value of removing weed contamination from seed that is being retained for planting, removing extraneous matter that can lead to problems in long-term storage and selecting the largest seed with the highest germination percentage and early vigour.

David Bach from Toowoomba Grain and Storage suggests David suggests harvesting much more grain than you need for seed, getting it cleaned and keeping the largest grain aside for seed.

David Bach from Toowoomba Grain and Storage suggests harvesting much more grain than you need for seed, getting it cleaned and keeping the largest grain aside for seed.

David Bach manages the family’s grain handling facility near Toowoomba, on Queensland’s Darling Downs. He says that since retained seed must be stored for longer than most grain is held on farm, it must be stored in optimal conditions. “Grading grain at harvest will remove trash such as leaf and stem material that can attract insects and mould while the grain is in storage, either awaiting sale or being retained for seed,” he says. “Once cleaned the seed then needs to be kept cool and dry to maintain seed quality.”

“When planning to retain seed on farm, select the best part of the paddock and harvest it first,” says David. “This way you will have collected the seed with the greatest vigour, which will provide the most competition for weeds in the early growth phase.”

If there is not an area of the paddock that is clearly better than the rest, David suggests harvesting much more grain than you need for seed, getting it cleaned and keeping the largest grain aside for seed.

“Grading it hard means that you have the best chance to remove a large proportion of the weed seeds present and you will also have a more consistent line of seed with the highest germination percentage,” he says.

“It is very important that grain is cleaned at harvest, before it is stored. Clean seed that is stored and managed properly can remain viable for over 9 years.”

David’s brother, Peter Bach manages the family’s farming operation—1620 ha of barley, wheat, sorghum, corn, mungbean and some faba bean—50 km west of Toowoomba.

Retaining seed not only represents a cost saving for them, it also provides a back-up if some or all of a paddock needs to be re-seeded for any reason.

Having a good supply of seed on hand means that growers can take advantage of favourable seasonal conditions. “We try to store enough seed here to plant half of the farm’s cropping area as soon as the soil moisture conditions allow,” says David. “This way we can make last-minute decisions and be confident that the seed we plant is clean and good quality.”

“Especially when the price is up it can be difficult to source seed, so we clean five times as much seed as we expect to use and store it,” he says. “To get that seed we might clean 120 tonne of grain and just keep the best 10 tonne for seed knowing that it has been thoroughly cleaned and graded.”

David cites black oats as the main problem in their area for barley and wheat crops, and sees that the wild turnip is soon going to be a major concern for growers.

“It pays to clean mungbean seed very hard,” he says. “Just one tonne of seed is required to sow 40 ha so it makes sense for that tonne of seed to be the very best that you have available, and free of weed seed contamination.”

Johnstone grass is the most difficult weed to remove from sorghum and maize crops in summer and David sees the herbicide tolerant hybrids providing some useful options for grass control in these summer crops.

However, he has noticed an increasing problem with herbicide resistant crops growing as volunteers in other crops and contaminating that grain. “For example, imi-tolerant sorghum might grow as a volunteer in another, conventional crop, and will not be controlled by the herbicides applied in that crop,” he says. “Further cross contamination can occur if that seed is unintentionally kept for planting. It is easy to become complacent about the herbicide tolerant crop plants growing on roadsides and the potential flow of seed from roadsides into grain paddocks.”

Seed cleaning equipment

There are several types of grain cleaning equipment available that vary in their efficiency when it comes to weed seed removal.

The Bachs use a rotary screen machine that has two main sections—1. an aspirator, where a fan sucks air through the grain, removing fine particles such as dust, and light material such as husks and some weed seeds and 2. the screens, where the grain rolls around inside a drum with different sized screens that allow the grain to be separated according to size.

“Usually the grain is sorted into two sizes plus the gradings or screenings, where the vast majority of weed seed is collected,” says David.

“Improving the grade of the sample is usually fairly simple, but cleaning for seed is much more time consuming and therefore costs more.”

“Sometimes growers think that their grain is cleaner than it really is,” says David. “On farms where the spraying is contracted out the farmer may not be as aware of the weed populations around their property.”

David says the value of having a commercial grain handling contractor do the seed cleaning lies in the contractor’s knowledge about how to set the machine up to achieve the best result. “The screens are expensive but it pays to use the right combination of screens to suit the grain and the weed spectrum,” he says. “It is probably not economic for a grower to invest in the large number of screens required to do the best job in all situations.”

“Grading table gear does an excellent job to remove weed seeds too,” says David. “These machines are most commonly found at commercial grain packing and processing facilities and could be a viable option for growers to use in some situations.”

Research conducted in Western Australia confirms David’s comments about the value of having seed cleaned by a specialist rather than using equipment, such as sieves or in-field rotary screens, that some growers use to clean their seed on farm.

Economics of seed cleaning

Growing seed for future planting needs to be a planned operation—start with clean seed, sow into a clean paddock, grow a competitive crop that suppresses weeds, keep the crop weed-free by taking action if individual plants survive treatment, harvest the best, cleanest part of the paddock, clean the seed hard and store it under optimal conditions. “Seed is very valuable and is worth investing in,” says David. “If you plant clean seed into clean paddocks the cost savings in time and herbicide will soon pay for the cleaning of the seed.”

To determine how many weed seeds are present in a potential seed lot, collect a 1 kg sample and separate the crop seed from all other material. 100 weed seeds per kilo of cereal or pulse seed sampled equals around one weed per square metre when the crop is sown.

A survey in Western Australia by the GRDC-funded Australian Herbicide Resistance Initiative found that un-cleaned seed samples can contain over 1500 weed seeds per 10 kg planting seed, which would add extraordinary pressure on the next crop. The AHRI survey found that the gravity table method of seed cleaning consistently produces the cleanest seed sample, reducing contamination to about 25 weed seeds per 10 kg. Sieves alone can bring the number down to about 150 weed seeds per 10 kg.

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What to expect at WeedSmart Week 2021

Big 6 at WeedSmart Week 2021 – Double knock to protect glyphosate
The WeedSmart Forum is set for Tuesday 17 August, 2021 at the Civic Centre in Esperance WA. The program features growers, agronomists and researchers discussing ways to use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
Greg Warren from Farm and General in Esperance will be sharing his thoughts on the control of weeds like summer-germinating ryegrass, marshmallow, fleabane and portulaca.
He says the growers around Esperance are tackling glyphosate resistance in annual ryegrass, along with brome and barley grass and other emerging weeds using a range of integrated control tactics. The double knock plays a key role in preserving glyphosate (and soil moisture) and providing a clean seed bed for planting crops.

 
Big 6 at WeedSmart Week 2021 – Increase crop competition
WeedSmart Week 2021 is set for Tuesday 17 to Thursday 19 August, 2021 in and around Esperance WA. The last two days feature local growers hosting visits to their farms and discussing how they use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
One of the farms hosting a visit during WeedSmart Week is Warrakirri’s 12,800 cropping operation at Condingup. Farm manager Con Murphy has implemented a variety of tactics to combat their main weeds – annual ryegrass and wild radish. Since 2015 the farm has undergone an intensive soil amelioration program to improve the drainage and ameliorate the sandy soils across the farm.
Con says the benefits have been seen in better germination and establishment that sets their cereal, pulse and canola crops up to compete strongly with weeds. There is also a benefit at the end of the season where rain in August or September enters the soil profile without causing waterlogging, and providing a better finish for their crops.
Since 2016-17 about 80% of the farm has been ripped and a portion has been ripped 2 or 3 times because the sandy soils tend to slump after substantial rainfall events, recreating the hardpan.
Con will be showing the WeedSmart tour group how their ripping, drainage, liming and spading program has helped grow more crop and less weeds!
Listen to the podcast with Warrakirri’s Con Murphy talking about the impact of improved drainage on crop competition

Big 6 at WeedSmart Week 2021 – Implement harvest weed seed control
The WeedSmart Week machinery display is set for Wednesday 18 August, 2021 at Dave Campbell’s shed near Esperance WA. The 3-day WeedSmart Week program features growers, agronomists and researchers discussing ways to use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
We’ve saved the harvest weed seed control discussion for the machinery session on Wednesday 18 August. Ben White from Kondinin Group will host the machinery session with spray and harvesting gear on display including impact mills from Seed Terminator, Redekop and iHSD (both hydraulic and belt-driven), Emar chaff deck, and spray technologies including Goldacres’ G6 Crop Cruiser series 2, and weed detection technologies using drones and weed identifying cameras (green on green).
Ben White, Kondinin Group (Photo: Melissa Powell, courtesy of GRDC)
Growers doing the WeedSmart Big 6
WeedSmart Week 2021 is set for Tuesday 17 to Thursday 19 August, 2021 in and around Esperance WA. The last two days feature local growers hosting visits to their farms and discussing how they use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
One of the growers who will open up their farm for a visit is Adrian Perks who farms at Condingup, 70 km north-east of Esperance. Adrian runs a continuous cropping program on his 4300 ha property, growing canola, wheat, barley, faba beans and lupins. This diverse rotation allows him to mix and rotate both chemical and non-chemical weed control tactics. Over half of Adrian’s farm is sandplain, on which he has implemented a soil amelioration program to address non-wetting to increase the competitiveness of his crops. He currently uses chaff decks for harvest weed seed control and is introducing an impact mill this season. Adrian monitors the tramtracks for weed growth and if he feels the weed pressure is too high, he uses a shielded sprayer to reduce seed set. The bus tour will include four farm visits and a machinery display.
Listen to Adrian on the Regional Update podcast.
Adrian Perkins, Condingup WA
 

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WeedSmart agronomist set to tackle high rainfall zone weeds

Every locality has its own spectrum of weeds, and growers face different opportunities and challenges regarding the control tactics they can employ.
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Commencing in January 2021, Jana Dixon has joined the WeedSmart team of extension agronomists, with a focus on applying the Big 6 to manage weeds in the high rainfall cropping systems of southern Australia – from Esperance in WA to south-eastern SA, Tasmania and south-western Victoria.
Jana will add to the dedicated and experienced extension agronomists on the WeedSmart team with Peter Newman in the Western region, Chris Davey in the South, Greg and Kirrily Condon in the East and Paul McIntosh in the North.
Jana Dixon has joined the WeedSmart team of extension agronomists, with a focus on applying the Big 6 to manage weeds in the high rainfall cropping systems of southern Australia – from Esperance in WA to south-eastern SA, Tasmania and south-western Victoria.
Jana hails from the Mid North of SA, and began working at Pinion Advisory (previously Rural Directions) while she was studying agriculture at the University of Adelaide. She has been employed full-time at Pinion Advisory since January 2019 as an agribusiness consultant, based in Clare, and spends most of her time delivering agronomy and farm business advice to clients from a wide range of cropping regions in South Australia.
Pinion Advisory is a foundation WeedSmart sponsor and Jana has been involved in two WeedSmart Week events already – the first as a participant and grower group organiser at the Horsham event in 2019 and then as the local organiser for WeedSmart Week 2020 in Clare.
In welcoming her to the WeedSmart team, program manager Lisa Mayer says Jana brings energy, commitment and insight to deliver communications focussed on the southern region’s high rainfall regions.
“Growers in the southern high rainfall zones are facing some serious issues with herbicide resistance influencing their farming decisions,” says Ms Mayer. “Jana will be engaging with agronomists, growers and researchers in each of the distinct high rainfall zones to understand the complexities and look for practical ways to apply the WeedSmart Big 6 in various cropping scenarios.”
“We plan to deliver WeedSmart Week in Esperance, part of Western Australia’s high rainfall cropping zone, in August 2021 and Jana will play a key role in the planning and delivering of our annual 3-day flagship event.”
Jana says her experience with the WeedSmart program has been very positive and she has been particularly impressed with the support the program has from all sectors of the grains industry.
Newly appointed WeedSmart extension agronomist, Jana Dixon (green cap) leading discussions with farm visit host, Ben Marshman, Owen SA, and growers and agronomists attending WeedSmart Week 2020 in Clare.
“I have spoken to many growers and agronomists who have found real value in the information that the WeedSmart program delivers,” she says. “For many it is as much about considering another operator’s philosophy on dealing with weeds, and taking a fresh look at their own systems, rather than just learning about a new tactic or the traits of a new herbicide in isolation from the big picture.”
She says the high calibre of industry people who contribute their time and expertise to the program is testament to the value WeedSmart has to agribusiness, growers, agronomists and researchers alike.
In taking on the responsibility for delivering information tailored for the high rainfall zones Jana says she is pleased to have an extensive network of contacts through Pinion Advisory, with offices in a number of high rainfall areas to provide easy access to local agronomists and growers. She is also aware that there are major differences in weed spectrums and farming systems in each high rainfall zone and plans to take full advantage of the opportunity this role presents to expand her understanding of different approaches to weed management.
“The long and favourable growing season and the associated prolonged periods of weed germination, is a key factor that I see potentially impacting on a grower’s weed management strategies in these regions,” she says. “On the other hand, access to highly diverse rotations and a focus on crop competition are two strategies that can play an important role in achieving excellent weed management in these regions.”
“I am keen to engage with anyone working and farming in the high rainfall zones to build my knowledge and understanding,” she says. “And to create opportunities to develop and extend the WeedSmart Big 6 strategies, both herbicide and non-herbicide, that work in each area and in different situations.”
WeedSmart is the industry voice delivering science-backed weed control solutions with support from the Grains Research and Development Corporation (GRDC), major herbicide, machinery and seed companies, and university and government research partners, all of whom have a stake in sustainable farming systems.
You an follow Jana on Twitter and keep up to date with the HRZ here.

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Never cut the herbicide application rate

Scientific studies have demonstrated that resistance can rapidly evolve in weeds subjected to low doses of herbicide. Some weeds can develop resistance within a few generations.
Full rates when mixing herbicides too!
When mixing herbicides it is important that each product is still applied at the full label rate to ensure high mortality.
Applying different chemicals in one mix can provide an additive advantage. It is important to understand the mode of action of each herbicide on the plant when preparing a herbicide mix. This is just as important for pre-emergent grass weed mixes as it is for post-emergent mixes aimed at broadleaf weed control. ALWAYS READ THE LABEL.
Surrounding weed seeds with a combination of pre-emergent herbicides with different modes of action can give a high level of control and help extend the useful life of all the chemicals used. The high level of control must be supported with additional control measures for all survivors. All products with different modes of action must be applied at full label rates for this to be an effective strategy.

 
Mixing two chemicals with the same mode of action can achieve some additional efficacy, however, the mix should deliver the combined full rate to ensure a lethal dose. The amount of stubble present and crop safety are all important considerations when mixing chemicals. For example, when using a tank mix of Avadex® and trifluralin to control ryegrass in wheat, the rates used will vary depending on the sowing system and level of stubble retention. Be sure to get good advice.
Many herbicides on the market are a combination of two or more modes of action within the one product. These products must be applied at the full label rate to be effective. Having dual action does not negate the need to change herbicide products and rotate modes of action. Repeated use of any single strategy will reduce the effectiveness of that strategy over time.
 

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