Image Upload

File size must be less than 2Mb

You must have online publishing permission or full ownership of this image

File types (jpg, png, gif)

  • Hero image
    WEEDSMART: Tim Rethus has encouraged other Wimmera and Mallee growers to attend the first Victorian WeedSmart Week, which will be in Horsham across three days from August 27.

AgLife: Opportunity to learn about ‘Big 6’

Weed management moves to a whole new level when you add the word ‘integrated’.

This is the driving force behind a WeedSmart Big 6 approach, which suggests that growers implement as many of these six key tactics as possible into their crop-management programs.

Farming in the Wimmera, the Rethus and Ruwoldt families have been working hard to build an integrated weed-management system that suits their farms.

In doing so they are ticking off many of the ‘Big 6’ tactics each season. These tactics are summarised as: 1. Crop and pasture rotation; 2. Double knock to protect glyphosate; 3. Mix and rotate herbicide groups; 4. Stop weed seed set; 5. Crop competition; 6. Harvest weed seed control.

Article continues below

In 2018 Tim Rethus and Ian Ruwoldt attended WeedSmart Week in Narrabri and this year they are backing WeedSmart Week in their own backyard.

This practical event in Horsham from August 27 to 29 also has the backing of the Birchip Cropping Group.

Tim and his brother Luke farm with their father Geoff and long-time worker Glenn in the central and southern Wimmera, where they are contending with Wimmera annual ryegrass, brome, wild oats, vetch, bifora, sow thistle and prickly lettuce.

“Our approach to weed control centres on keeping weed germination levels low and using diverse farming practices,” Tim said.

“Dad was an early adopter of minimum tillage back in the early 1980s and we have progressively moved to farming systems that involve less disturbance. One of the major benefits is that we are leaving the weed seeds on the soil surface where they are exposed to the weather and don’t have the soil contact they need, and this really reduces weed-seed germination.”

A key element to the Rethus’ success is their determination to achieve near-zero disturbance at planting.

When they adopted a 40-foot CTF system in 2008 their min-till single-disc seeder did a good job and reduced soil throw. 

Ten years on, the soil in the cropping beds has responded to the removal of machinery traffic, and the single discs were often stalling in the softer soil and the depth control was no longer adequate.

This led the Rethus’ to invest in a zero-till precision planter to provide more precision at planting, including inter-row sowing for lentils, and to make best use of the newest chemistry available. 

“This precision seeder was a good unit but it was complex and didn’t suit all our crops,” Tim said.

“So, we decided to combine the precision row units with twin-disc openers on a new 80-foot NDF frame but use an air-seeder to deliver the seed.”

To further reduce soil throw, residue managers are not used. Instead ‘PTT Sabre-tooth’ discs are used to cut through the residue and reduce pinning.

“Adding side-shifting rams to the toolbar means we can also inter-row sow our lentils and we have a seeder that meets all our requirements, especially in terms of maintaining low weed-seed germination at seeding while still sowing at 15-inch row spacing,” Tim said. 

The Rethus family practices a diverse crop rotation of wheat, barley, durum, canola, lentils, beans and oats, and use shielded spraying, hay production, brown manuring, spray topping and diverse herbicide strategies to minimise weed-seed set.

Tim said the reality of herbicide resistance meant non-chemical tools were important to maintain low weed numbers and this was one of the driving forces behind their efforts to fully integrate hay production into their CTF system.


Farming at Kewell, Ian Ruwoldt and his brother Greg also have several strategies in place to manage ryegrass, bedstraw, marshmallow, vetch and bifora.

Ian found the WeedSmart event to be comprehensive and a good opportunity to think through tactics that could help solve their weed problems.

“We currently use oaten hay, chemical rotation, imidazolinone chemistry with canola and a chaff deck on the harvester to keep weed numbers low,” he said.

“Thinking about the WeedSmart Big 6 helps to formulate a plan to manage weeds through the year and through the rotation.

“The forum covers a lot of topics and the discussions are practical and relevant to the region, so this year’s event will focus on the weed issues facing Wimmera and Mallee farmers.” 

Attendees will have several opportunities to see and discuss cutting-edge technologies such as optical sprayers, robots and emerging ‘green-on-green’ spray sensors. They will also find out how other growers in the region are implementing the Big 6.

Growers, agronomists and researchers speaking and participating in expert panels at the forum will spark important discussions about herbicide resistance and how the Big 6 tactics can target weed species and farming systems in the southern cropping region.

People can register for the three-day event at

The entire July 31, 2019 edition of The Weekly Advertiser is available online. READ IT HERE!

The entire July 31, 2019 edition of AgLife is available online. READ IT HERE!