Crop competition

Optimise crop growth

We don’t want to give the weeds a free kick by growing un-competitive crops. Crop competition with weeds is a double-edged sword. There is the effect of the weeds on the crop, and the effect of the crop on the weeds. A competitive crop will suffer less yield loss at the hands of the weeds, and will also reduce seed set of the weeds compared to an un-competitive crop. In other words more crop, fewer weeds.

There are six main aspects of crop competition:

Higher seeding rate
Narrow row spacing
Orientation of crop – a crop sown east – west will give your crop enough sunlight, and shade the furrows to starve weeds of sunlight
Vigorous crop traits
Soil health – give your crop the best chance by having healthy soil
Time of sowing – early sowing is usually best

It’s hard to get all of the six points above right, and growers need not aspire to practise all six of these competition factors, but they can use a range of these practices to ensure that their crops have a fighting chance against the weeds.

The checklist:

Adopt at least one competitive strategy, but two is better.
Target higher plant populations using increased seeding rates, weed-free seed tested for germination, vigour and 1,000 seed weight.
Aim for even seed distribution and establishment.
Sow competitive crop types and varieties.
Improve soil health (fertility and structure) and crop nutrition, e.g., soil amelioration (if necessary), no-till, stubble retention, nutrient budgeting.
Utilise early sowing and adopt East/West sowing if practical.
Reduce row spacing where possible.

You can learn more about crop competition in our free online course, Crop Competition 101.

Articles

View all

Case Study

Langley family, Winchelsea, Vic

The Langley's farming system demonstrates how alleviating soil constraints can benefit both crop production and weed suppression. Read More...

News

WeedSmart Big 6 on medium to low rainfall farms in NSW and Victoria

Get started with the WeedSmart Big 6 tailored for the medium and low rainfall regions of Victoria and southern New South Wales. Read More...

News

Cost-effective dual HWSC modes

Using two modes of harvest weed seed control can maximise the feed value for livestock and minimise the impact of burning chaff. Read More...

Case Study

Craig Bignell & Sarah Robinson, Broomehill, WA

The WeedSmart Big 6 is keeping weed numbers down and reducing the impact of herbicide resistance on the Bignell’s mixed farming enterprise. Read More...

Ask an Expert

Have we lost some key herbicides in the Northern region?

Dr Michael Widderick says the latest weed survey has uncovered increasing resistance to glyphosate, paraquat and 2,4-D in key weeds. Read More...

Case Study

Krui Pastoral Co, Condamine, Qld

East-west sowing is a legacy of the Hamilton's land clearing for livestock, providing paddock-wide weed suppression. Read More...

Case Study

Slarke family, Lake Grace WA

The Slarke family implement an integrated weed management program to minimise the impact of herbicide resistance on their farming business. Read More...

News

Crop competition from the ground up

At Lake Grace, WA, the Slarkes use narrow row spacing, high seeding rates, east-west sowing, VRT and soil amelioration to help combat weeds. Read More...

Ask an Expert

What are the options to manage glyphosate- and paraquat-resistant ryegrass?

Dr Roberto Busi, AHRI says annual ryegrass with resistance to both glyphosate and paraquat demands a change in fence line weed management. Read More...

News

WeedSmart Big 6 on High rainfall farms in the Southern and Western regions

Get started with the WeedSmart Big 6 tailored for the high rainfall regions of Victoria, South Australia and Western Australia. Read More...

News

WeedSmart Big 6 on WA’s Low and Mid rainfall farms

Get started with the WeedSmart Big 6 tailored for the low and mid rainfall regions of Western Australia. Read More...

News

WeedSmart for organic croppers

The Jacksons developed valuable weed management tactics that can be employed in both conventional and organic farming systems. Read More...

News

Measuring the value of weed control expenses

Chris Davey, WeedSmart's southern extension agronomist, suggests three ways to reassure yourself that a weed control tactic is worthwhile. Read More...

Ask an Expert

What are the economic benefits of diverse rotations?

Crop choice and rotation planning are very powerful weed control tactics, central to a biologically-robust and sustainable farming system. Read More...

News

Never miss an opportunity to tackle weeds

One of the main benefits of using harvest weed seed control is that the Turners still have many newer herbicide products up their sleeve. Read More...

Case Study

Rhys Daniels, Capella Qld

The Daniels run a predominantly summer-cropping program and have many tactics in place to keep their weed numbers down. Read More...

Ask an Expert

Can annual ryegrass be beaten in the Northern region?

Scout paddocks and farm borders for incursions of annual ryegrass and be aware of biosecurity hazards like contract machinery and hay. Read More...

News

Tackle weeds and herbicide resistance with the Big 6

Nutrien agronomists from across the country share their tips to help control crop weeds using the WeedSmart Big 6 strategy. Read More...

Ask an Expert

What is the value of fixed nitrogen for suppressing weeds?

Competition in crops after pulses is a major weed management benefit, and the direct weed control options in pulses have also improved. Read More...

Ask an Expert

How can I best tackle sterile oat in Northern region wheat crops?

Control all emerged sterile oat seedlings over two years and prevent seed bank recruitment to eliminate this competitive weed. Read More...

News

Plan your attack on the weed seed bank

Here we summarise the key components of the WeedSmart Big 6 strategies and the principles that underpin them. Read More...

Ask an Expert

How can I make the most of spring planning sessions?

Spring planning sessions are vitally important for growers and agronomists to keep ahead of weeds and herbicide resistance. Read More...

News

Reining in FTR with cultivation and competition

Since introducing this strategic cultivation regime, the Daniels have not had a problem managing feathertop Rhodes grass. Read More...

News

Resistant ryegrass challenges disc seeding systems

With limited pre-emergence herbicide options registered for use with disc seeders, growers must implement other weed control strategies. Read More...

News

Power of crop rotation to combat herbicide resistance

It only takes one resistant plant to break an effective herbicide if selection pressure is high, and survivors set seed. Read More...

Case Study

Michael & Marnie Fels, Wittenoom Hills WA

Narrow rows, stacked rotations and chaff lining at harvest are the central components to the Fels' weed management program. Read More...

News

WeedSmart Big 6 on Mid North, Yorke Peninsula and Lower Eyre Peninsula farms

Get started with the WeedSmart Big 6 tailored for the Mid-North, YP and lower EP region of South Australia. Read More...

Case Study

Wayne Zeisemer, Bongeen Qld

Wayne Zeisemer tackles hard-to-kill weeds with an optical spot sprayer, residual herbicides, strategic tillage in the fallow and zonal tillage to prepare a weed-free seedbed. Read More...

News

Investigating the role of competitive wheat against three northern region weeds

Weed ecology highlights integrated weed management tactics for common sowthistle, Mexican poppy and turnipweed in the northern grains region. Read More...

Case Study

Simon Burgess, Conara Tasmania

Reconfiguring paddocks for irrigation can bring up many issues related to previous management and land use, including weeds. Read More...

News

Stop ryegrass in its tracks: First step is to prevent seed set

Bec and Ash Marshall have seen the benefits of resistance testing and implementing tactics that drive down weed numbers fast. Read More...

Ask an Expert

How can I strengthen the pulse phase to combat weeds?

Many herbicide-tolerant pulse varieties are very specific in their tolerance to different active ingredients, even from the same mode of action group. Read More...

Ask an Expert

How can I use the WeedSmart Big 6 to keep old chemistry working?

Any herbicide program that relies heavily on one or two herbicide modes of action for a target weed is bound to fail eventually. Read More...

News

Caution required when retaining rain-affected seed

To avoid poor germination and low vigour crops, retain seed from fertile paddocks and avoid diseased, sprouted or weather-damaged grain. Read More...

Case Study

Michael Nichols, Sisters Creek, Tas

When herbicide resistant annual ryegrass arrived on their farm Michael Nichols knew he needed to prevent a ‘stop farming’ event. Read More...

News

Best seed, best establishment, fewer weeds

Sowing large canola seed, regardless of the cultivar, is key to strong early crop growth and the crop’s ability to compete with weeds. Read More...

Ask an Expert

How does crop competition support other weed control tactics?

Crop competition is a quiet achiever in weed control that also has a synergistic effect when applied with other tactics. Read More...

Ask an Expert

Can faba bean crops outcompete sowthistle?

Faba bean crops have the potential to significantly curb common sowthistle, a problematic weed with widespread resistance to key herbicides. Read More...

News

Australian grain growers tackle herbicide resistance

Australian grain growers are responding to the challenge of increasing herbicide resistance in weeds through the adoption of IWM practices. Read More...

Ask an Expert

How to beat barley grass in two years

Barley grass control requires a two-year, multi-pronged strategy using crop competition, herbicide-tolerant crops and effective in-crop herbicides. Read More...

News

Ryegrass is adapted to a wide climatic range

Once considered a winter weed of southern cropping zones of Australia, annual ryegrass is being increasingly observed in more northerly districts and in summer crops in Victoria and South Australia. Read More...

Case Study

I’Anson Family Farms, Marrabel SA

Kym and Katie I’Anson are treating the serious soil constraints on their farms to grow more even crops and squeeze out the weeds. Read More...

News

Invest in the weak link crop to avoid weed blow-out

South Australian farmers, Kym and Katie I'Anson, have added multiple tactics to control ryegrass in wheat, their weakest link crop. Variable rate lime, gypsum and seed has increased crop competition and the double knock and impact mill keep the fields clean. Read More...

News

Double down on the double break in the high rainfall zone

A long-term trial at Lake Bolac demonstrated the strategies that control ryegrass in high rainfall zone cropping systems. Read More...

Ask an Expert

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

Field pea provides an effective winter fallow clean to manage resistant ryegrass ahead of planting rice or wheat. Read More...

Ask an Expert

Can multi-species planting provide effective weed control?

Some crops simply don’t have a competitive edge, but a multi-species planting might offer extra punch to smother weeds. Read More...

Case Study

Jamie and Susie Grant, Jimbour Qld

Proactive use of automated optical weed detection technology, allows continuous spraying and treating smaller and smaller weeds. Read More...

Case Study

Peter and Kylie Bach, Pittsworth Qld

Peter and Kylie Bach are using crops to compete with weeds throughout the year, aiming for 130% utilisation of their cropping land. Read More...

Ask an Expert

How can I set up my summer crops to help manage weeds?

It pays to plan ahead to manage weeds in winter fallows destined from summer crops – such as cotton, sorghum, mungbean and sunflower. Read More...

Ask an Expert

What strategies will rein in wild turnip in the northern region?

Wild turnip steals crop yield and requires additional control measures that together cost over $10 million every year across Australia. Read More...

News

Remove the fetters from crops and they’ll trample the weeds

Addressing soil constraints, such as low pH (and the associated aluminium toxicity), enables the crop to compete strongly with weeds. Read More...

Ask an Expert

How can I maximise grass weed control using hybrid canola?

For a competitive canola crop to halve grass weed seed set, use a vigorous variety, robust pre-em herbicide and the best agronomic package. Read More...

Case Study

Single family, Coonamble NSW

The Singles gain good weed control year round using crops and fallow in both winter and summer on their farm near Coonamble. Read More...

Case Study

Jason Rogers, Moree NSW

Keeping weed numbers down, managing patches and minimising weed seed set has been a high priority for Jason Rogers, Moree. Read More...

Case Study

Andrew Kenny, Badgingarra WA

Andrew and Gina Kenny (Badgingarra, WA) use an integrated program of crop rotation, mouldboard ploughing, grazing and chaff lining to keep their weed numbers low. Read More...

Article

Crop competition – give your crops the edge

Optimise crop growth We don’t want to give the weeds a free kick by growing un-competitive crops. Crop competition with weeds is a double-edged sword. There is the effect of the weeds on the crop, and the effect of the crop on the weeds. A competitive crop will suffer less yield loss at the hands […]...

Article

Spray drift & crop competition

Ask an Expert

Does delayed sowing help manage weed populations?

Case Study

Stephen and Michelle Hatty, Matong NSW

The Hatty family uses a double break crop sequence strategy of a pulse then canola, followed by wheat then barley to put firm downward pressure on the weed seed bank. Read More...

Case Study

Tim Rethus, Horsham Vic

Wimmera grower Tim Rethus and his family are taking an integrated approach to the weed management with a strong focus on weed-free crops. Read More...

Ask an Expert

What’s the best way to out-compete resistant annual ryegrass in cereals?

News

Creating stiff competition against summer weeds

Case Study

Bruce family, Alford SA

Harvest weed seed control helps bring down grass weed numbers in the Bruce brothers' continuous cropping business. Read More...

Case Study

Edwards family, Port Broughton SA

Pete Edwards is doing everything in his power to stop herbicide resistance in brome grass and wild radish. Read More...

News

Getting the edge on brome grass on non-wetting soils

News

Winter pulses can compete, even without herbicide

Ask an Expert

What is the critical period for weed control?

Once a crop has passed the critical period for weed control, the crop should out-compete any new weed germinations. Read More...

News

3-year strategy for sustainable brome grass management

Ask an Expert

Is it possible to apply additional competition to inter-row weeds?

Ask an Expert

Stewardship of synthetic auxin herbicides

News

Zero row spacing could take crop competition to a new level

Case Study

Gary Lang – Wickepin, WA

Sowing early also means the Langs can make use of trifluralin to provide pre-emergent weed control until the crop canopy closes. Read More...

News

Ramp up the competition in summer crops

Case Study

Kohlhagen Family, NSW

The Kohlhagens have developed and implemented a comprehensive weed management program for their 100 per cent cropping operation in southern NSW. Read More...

News

Why consider sowing east-west?

Case Study News

Making clean seed your business

Grading and cleaning seed for planting removes weed seeds and selects the largest seeds with high vigour to out-compete weeds next season. Read More...

Case Study

Mark Sandow, SA

Herbicide-resistant annual ryegrass has been an ongoing challenge for grain producers in the Mintaro area of South Australia since the 1980s. Read More...

Case Study

Colin McAlpine, WA

Colin has thrown everything he can at reducing the weed burden on his farm while taking all precautions to protect the available herbicide modes of action. Read More...

Podcasts

View all

Podcast

S09E08: Deep placement of phosphorus and potassium (P&K)

Deep placement of phosphorus and potassium can improve crop nutrition and therefore improve crop competition, helping you control weeds. We talked with Mike Bell, who has been focused on deep placement of P&K, and Kurt Mayne, who has been implementing it into his operation in QLD. Read More...

Podcast

S08E18: What’s better out of hybrid and open-pollinated canola?

In this podcast, we’re talking about hybrid canola and how it might benefit your farming system. Read More...

Podcast

S08E16: Enemy number one was ryegrass at Dubbo WeedSmart Week

In this podcast, we hear about the key messages shared by presenters and panel members at WeedSmart Week Dubbo. Read More...

Podcast

S08E15: Regional Update – Jason Coleman, Grower, Temora, NSW

Temora grower, Jason Coleman, joins us on the podcast today to give a recap on his experience at WeedSmart Week Dubbo. Read More...

Podcast

S07E15: Faba beans pack a punch against sowthistle

Dr Michael Widderick explains what gives faba beans the competitive edge when it comes to out-competing sowthistle. Read More...

Podcast

S07E07: Competitive and profitable crops from fixing sub-soil acidity

Using soil amelioration to fix sub-soil acidity can lead to huge yield and profit gains. Read More...

Podcast

S07E03: Longer coleoptile wheat protects seedlings from herbicide damage

Wheat with a longer coleoptile offers some unique crop protection benefits. A weeds trial, which shows a triple threat strategy rather than traditional methods, could produce the best weed control results in the Southern region. Read More...

Podcast

S06E08: Innovative northern grower shares wins and Roundup Ready Xtend stewardship

Hear from Northern Grower Bruce Watson on his weed control wins and learn about the stewardship of Bayer's Xtend technology. Read More...

Podcast

S06E04: Narrower sorghum rows can halve weed seed production

Dr Michael Widderick joins us to explain research which found that narrower row spacing in sorghum leads fewer weeds. Read More...

Podcast

S06E02: Upwards of 90% weed seed burial with some soil amelioration approaches

Research Scientist, Dr Stephen Davies, joins us to explain what’s involved with soil amelioration and the benefits of this approach in this podcast. Read More...

Podcast

The unsung hero – crop competition

Podcast

Companion and intercropping piquing interest of Aussie farmers

Podcast

Weather forecast accuracy and crop competition trial results

Podcast

Disc seeding systems

Case Studies

View all

Case Study

Langley family, Winchelsea, Vic

The Langley's farming system demonstrates how alleviating soil constraints can benefit both crop production and weed suppression. Read More...

Case Study

Craig Bignell & Sarah Robinson, Broomehill, WA

The WeedSmart Big 6 is keeping weed numbers down and reducing the impact of herbicide resistance on the Bignell’s mixed farming enterprise. Read More...

Case Study

Krui Pastoral Co, Condamine, Qld

East-west sowing is a legacy of the Hamilton's land clearing for livestock, providing paddock-wide weed suppression. Read More...

Case Study

Slarke family, Lake Grace WA

The Slarke family implement an integrated weed management program to minimise the impact of herbicide resistance on their farming business. Read More...

Case Study

Rhys Daniels, Capella Qld

The Daniels run a predominantly summer-cropping program and have many tactics in place to keep their weed numbers down. Read More...

Case Study

Michael & Marnie Fels, Wittenoom Hills WA

Narrow rows, stacked rotations and chaff lining at harvest are the central components to the Fels' weed management program. Read More...

Case Study

Wayne Zeisemer, Bongeen Qld

Wayne Zeisemer tackles hard-to-kill weeds with an optical spot sprayer, residual herbicides, strategic tillage in the fallow and zonal tillage to prepare a weed-free seedbed. Read More...

Case Study

Simon Burgess, Conara Tasmania

Reconfiguring paddocks for irrigation can bring up many issues related to previous management and land use, including weeds. Read More...

Case Study

Michael Nichols, Sisters Creek, Tas

When herbicide resistant annual ryegrass arrived on their farm Michael Nichols knew he needed to prevent a ‘stop farming’ event. Read More...

Case Study

I’Anson Family Farms, Marrabel SA

Kym and Katie I’Anson are treating the serious soil constraints on their farms to grow more even crops and squeeze out the weeds. Read More...

Case Study

Jamie and Susie Grant, Jimbour Qld

Proactive use of automated optical weed detection technology, allows continuous spraying and treating smaller and smaller weeds. Read More...

Case Study

Peter and Kylie Bach, Pittsworth Qld

Peter and Kylie Bach are using crops to compete with weeds throughout the year, aiming for 130% utilisation of their cropping land. Read More...

Case Study

Single family, Coonamble NSW

The Singles gain good weed control year round using crops and fallow in both winter and summer on their farm near Coonamble. Read More...

Case Study

Jason Rogers, Moree NSW

Keeping weed numbers down, managing patches and minimising weed seed set has been a high priority for Jason Rogers, Moree. Read More...

Case Study

Andrew Kenny, Badgingarra WA

Andrew and Gina Kenny (Badgingarra, WA) use an integrated program of crop rotation, mouldboard ploughing, grazing and chaff lining to keep their weed numbers low. Read More...

Case Study

Stephen and Michelle Hatty, Matong NSW

The Hatty family uses a double break crop sequence strategy of a pulse then canola, followed by wheat then barley to put firm downward pressure on the weed seed bank. Read More...

Case Study

Tim Rethus, Horsham Vic

Wimmera grower Tim Rethus and his family are taking an integrated approach to the weed management with a strong focus on weed-free crops. Read More...

Case Study

Bruce family, Alford SA

Harvest weed seed control helps bring down grass weed numbers in the Bruce brothers' continuous cropping business. Read More...

Case Study

Edwards family, Port Broughton SA

Pete Edwards is doing everything in his power to stop herbicide resistance in brome grass and wild radish. Read More...

Case Study

Gary Lang – Wickepin, WA

Sowing early also means the Langs can make use of trifluralin to provide pre-emergent weed control until the crop canopy closes. Read More...

Case Study

Kohlhagen Family, NSW

The Kohlhagens have developed and implemented a comprehensive weed management program for their 100 per cent cropping operation in southern NSW. Read More...

Case Study News

Making clean seed your business

Grading and cleaning seed for planting removes weed seeds and selects the largest seeds with high vigour to out-compete weeds next season. Read More...

Case Study

Mark Sandow, SA

Herbicide-resistant annual ryegrass has been an ongoing challenge for grain producers in the Mintaro area of South Australia since the 1980s. Read More...

Case Study

Colin McAlpine, WA

Colin has thrown everything he can at reducing the weed burden on his farm while taking all precautions to protect the available herbicide modes of action. Read More...

Videos

View all

Webinar

Beating barley grass despite resistance and dormancy challenges

Learn how to control barley grass despite increasing dormancy and resistance challenges. Read More...

Webinar

How faba beans pack a punch against sowthistle

Research shows there are opportunities to alter the agronomy of faba beans to suppress sowthistle growth and seed production in crop. Read More...

Video

Season long control with crop competition

Video

Farming moisture : Beating weeds

Video

Soil health produces more crop, less weeds

Video

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

Rod Birch (Coorow, WA) gives an overview of what Big 6 principles are working for them. He also explas how they're approaching weed control at new property acquisition, 'Koobabbie', which hadn't changed hands for 115 years. Read More...

Video

WeedSmart Week Forum Day Videos

Watch all the videos from our Esperance WeedSmart Week Forum Day! Read More...

Webinar

What’s next in the North for weed control?

Agronomists Peter McKenzie and Angus Dalgliesh discuss the weed control tactics their clients have been using to deal with their weed challenges. Read More...

Webinar

Ryegrass management in the High Rainfall Zone – What have we learnt?

Join Dr Chris Preston (University of Adelaide) and James Manson (Southern Farming Systems) as they discuss how the WeedSmart’s Big 6 strategies are best utilised to combat annual ryegrass in the High Rainfall Zone of South Eastern Australia. Read More...

Webinar

Handling weeds in a strip and disc system

Webinar

You don’t know what you don’t know about managing weeds

Webinar

WeedSmart in HRZ – practical options for dealing with ryegrass

Fact Sheets

View all

Fact Sheet

Control barley grass in LRZ farming systems

Barley grass in Southern and Western regions requires 3 to 4 years of seed set control to run down the weed seed bank. Read More...

Fact Sheet

Wild radish factsheet

Growers are adopting diverse and integrated control strategies to manage herbicide resistant wild radish populations. Read More...

Fact Sheet

Northern IWM factsheet – common sowthistle

Understand the ecology of common sowthistle and effective management tactics. Read More...

Fact Sheet

Windmill grass – Northern Region

Understand the ecology and effective management tactics to better manage this key weed. Read More...