Windrowing barley plus HWSC in the high rainfall zone
The Williams family began harvest weed seed control in 2017 when they introduced a seed impact mill to their weed management program.
Although they were apprehensive about the large initial outlay for the second Seed Terminator prototype (MY17), after six years using an impact mill, Tim Wiliams says their investment is paying off with less weed pressure and less chemical applied.
“There have been massive improvements in mill technology since 2017, resulting in reduced horsepower requirement and increased fuel efficiency,” he says. “Harvest economy kept improving as we progressed from the prototype mill on a John Deere S670 to the 780 and now have the 2022 model Seed Terminator on a 9.90 New Holland harvester.”
Even in the high rainfall zone (650 mm annually), the Williams use the standard screens in the mill to maintain the high weed seed kill rate of 99 per cent across their continuous cropping program of wheat, barley and faba beans. The problem weeds on their 1100 ha property at Conmurra in south-east South Australia are annual ryegrass, wild oats and bedstraw.
“We use our barley phase to really drive down the weed seed bank,” says Tim. “We windrow the barley as early as possible, even if that means sacrificing a little yield, and cut it as low to the ground as possible. This minimises seed shedding, particularly in ryegrass, so we can capture the seed and process it through the mills.”
When the Williams were looking into their options for harvest weed seed control, they chose mills rather than a chaff cart or chaff lining due to the high amount of chaff, and limited opportunities to burn, potentially interfering with seeding. Tim uses a disc seeder on 20 cm row spacing and has recently dropped pre-emergents from their herbicide program in barley.
“We hit weeds pretty hard in barley and have reduced weed numbers across the farm,” he says. “With the discs, we rely on Boxer Gold and don’t want to over-use it to the point of generating resistance. Applying pre-emergent chemistry in the wheat and faba bean crops is more beneficial in our program.”
When windrowing, Tim usually starts on the opposite side of the paddock to where the seeder began, to pick up any lodged weeds in the inter-row and make sure they are cut and placed in the windrow.
“We started out using a windrowing front on the header, which cut the stems quite high,” says Tim. “The windrowed material then tended to sink into the stubble and was hard to pick up later with the harvester. We now have a self-propelled windrower and cut as close to the ground as possible – beer can height or even lower in weedy areas.”
In the bean phase, the Williams no longer practice desiccation because they find it increases the amount of dust present at harvest. Instead, they find the straw separation system with the Seed Terminator mill does a good job of keeping the green material out of the mills and off the sieves.
“The standard separation belt in the New Holland is about 60 cm long, but the Seed Terminator belt is over 1.5 m and does a much better job than the baffles we had in our previous John Deere harvesters,” says Tim. “Keeping green stems and green weeds like thistles and radish out of the mills avoids blockages, even in high yielding and bulky crops.”
Seed Terminator representative Mark Bastian says the company has brought to market several features that make their seed impact mills a very effective option for growers in the high rainfall zones.
“The Seed Terminator mills can achieve weed kill rates of up to 99 per cent for annual ryegrass,” he says. “There are four screen types available, but the standard screen is the most common in the high rainfall zone. The other options, including blanking screens, bean screens and green screens, can be swapped in just 20 minutes if needed.”
Mark says harvesting in the cool, damp conditions in the high rainfall zone is not a problem with their seed impact mills as there is often less damage to the straw and the mills are set up to keep the straw and the chaff streams separate, which results in less ‘MOG’ or ‘material other than grain’ on the sieves. If necessary, the harvest operator can bypass the Seed Terminator mill.
Harvest weed seed control is one of the WeedSmart Big 6 tactics to limit the impact of weeds that have evaded herbicide during the cropping phase. Three companies offer seed impact mills in Australia, and all are WeedSmart partners.
More resources
