Big 6 keeps weed numbers low in the HRZ
Bingham Agriculture’s farm manager, Sam Sedgewick says the suite of herbicide-tolerant canola hybrids is a great way to clean grass weeds out of a paddock, and the double-break effect with faba beans can drive the next three years of wheat production.
Producing wheat, canola, faba beans, wool, first cross-ewes and prime lambs, owners, Dan and Jill Bingham run a 5500 ha diversified farming operation based at Mingay, in the high rainfall zone of southwest Victoria.
In recent years, they have introduced summer cover cropping on a portion of the farm, adding another dimension to the summer weed control program.
“After harvesting our RR canola crops, we spray for weeds and allow the volunteer canola to grow over summer,” says Sam. “The resulting cover crop provides additional high-quality grazing for the sheep, uses up any excess water and keeps the soil microbe populations active.”
Tim Dunne, cropping manager says they are proactive in adopting the WeedSmart Big 6 tactics within their farming system to keep weed numbers low and to extend the useful life of various herbicide modes of action.
Annual ryegrass and wild radish are the main problem weeds on the farm, and they are keeping a watchful eye on brome grass and bedstraw.
“Our independent agronomist, Ben Dumnesy, oversees our annual herbicide resistance and soil testing program and has a key role in our crop rotation planning to ensure we are optimising crop performance and keeping the weed seed bank low across the farm.”
As their cropping enterprise has expanded, they have adopted several innovations in farm layout, variable rate technology, and raised-bed controlled traffic systems. The sheep grazing enterprise is confined mainly to 500 ha of pastures, while the internal fencing on the cropping area delineates management units of around 200 ha each. Bringing together paddocks with different cropping histories has presented several challenges to crop performance and weed pressure that the agronomy team continues to work through.
About half of the cropping area has been developed for improved drainage on heavy clay soils. The raised bed system has overcome issues with poor crop growth and the associated proliferation of weeds, particularly annual ryegrass. The rest of the cropping area is well drained but has benefitted from deep ripping to address soil compaction constraints.
The philosophy behind their adoption of VRT is to ‘spend money in the best way, not to save money’.
The company started using harvest weed seed control (HWSC) in 2018 when the first of their three iHSD impact mills for use on their own farms and within their contract harvesting business.
Sam says that other growers appreciate the harvest weed seed control concept but generally find it hard to see past the initial outlay and reduction in harvest productivity.
“For our farm, HWSC has limited value in the long season red wheat crops because most of the weed seed has shed before the crop is ready to harvest,” says Sam. “However, it is a very effective tactic to deploy in canola and barley when combined with windrowing.”
The real value of HWSC was seen when two of the Bingham’s dirtiest paddocks were as clean as their best paddocks after two consecutive seasons using the iHSD impact mills.
Bingham Ag uses their large spray capacity to take advantage of small spray windows with good weather conditions.
“We have three staff members who specialise in spray operations,” says Sam. “We always target small weeds, use high water rates (80 to 100 L/ha) to ensure adequate coverage of the target, and choose nozzles that produce coarse droplets.”
Tim says they are working hard to reduce their overall herbicide use across their operation and have moved away from relying on ‘out-of-the-drum’ solutions to pests and weeds.
From a weed management perspective, this means investing in soil health and growing the best crop possible, so there is less reliance on herbicides.
Each farm has its own water source and mixing station to maximise spray efficiency. Chemicals are delivered to the paddock from a central farm store, negating any need for a fill truck.
Currently, herbicide resistance is not calling the shots in the Bingham’s crop rotation, but the team considers the resistance testing results when preparing the herbicide program.
“We certainly have some resistance to herbicides, so our focus is on keeping weed numbers low,” says Tim. “The pre-emergent herbicide application is the most important one of the season. We rotate modes of action within the suite of pre-ems to keep our options open. For instance, we save all our Group 1 [A] herbicides for use only in canola.”
To suppress weeds and maximise yield, the Bingham Ag team puts great emphasis on their seeding operation to establish a competitive crop.
“We aim for a plant density of 200 plants per m2 in wheat and 50 plants per m2 in canola,” says Sam. “This plant population gives us a dense crop and rapid canopy closure on 250 mm (10-inch) row spacing. We also aim to get the crop in on time and up out of the ground quickly.”
The WeedSmart Big 6 strategy embraces herbicide and non-herbicide weed control tactics to keep weed numbers low in cropping systems. The latest weed control tactics and technologies will feature at WeedSmart Week in Port Lincoln on 29–30 July 2024.
