ALTHOUGH disc seeders have had their share of teething problems, farmers who have made the switch generally remain convinced of making long-term gains by switching from a traditional knife-point set-up.
Jack Desbiolles, a researcher into sustainable farming systems with the University of South Australia, said that a 2007 survey of farmers using disc seeders found that although there were a number of drawbacks, farmers believed the long-term benefits of going to a zero till cropping system more than outweighed the negatives.
Dr Desbiolles said overall cropping system benefits, primarily in the form of the ability to retain stubble due to the disc seeder’s improved ability to get through crop residue when planting the next year, was the major deciding factor in converting across to discs.
The Grains Research and Development Corporation (GRDC) supported survey into the use of disc seeders found that a whopping 95pc of those using discs used them to plant into retained standing stubble.
“The ability to retain stubble, and by extension, retain ground cover is one of the key drivers in people using disc seeders,” Dr Desbiolles said.
He said reducing the need for stubble management was another spin-off benefit, cutting down on the cost and time involved in either mulching or burning paddocks.
However, the discs are far from the perfect fit for Australian croppers.
Dr Desbiolles said the survey confirmed suspicions that the discs struggled to compete with knifepoint set-ups when confronted with wet sowing conditions and heavy clay soils, while there were also reports of inadequate herbicide incorporation with products such as trifluralin, which requires sowing to incorporate into the soil.
Although the discs are generally well regarded in dry conditions, Dr Desbiolles said farmers had to monitor progress closely to ensure there was adequate ground penetration, especially in hard, dry conditions.
He said advances in technology were being made, especially in the design of discs that work better in wet conditions, which were making discs a more viable proposition.
“There is work with designs such as fluted discs, or tangential discs, which have sown some success in getting through wet conditions.”
With sowing date becoming recognised as an increasingly important part of farmers’ thinking in terms of planting, the ability to cover large amounts of ground quickly and to be able to dry sow is also a big plus for the disc seeder.
“There are time and cost savings, with reduced fuel, seed and labour inputs required,” he said.
The disc seeders also have a strong fit in no-till systems in low rainfall zones, as the stubble retention allows for better moisture savings, allowing crops to germinate in marginal conditions.
No-till systems, in particular the discs, come under fire from some for a perceived lack of weed management options.
However, Dr Desbiolles said generally the lower soil disturbance levels meant fewer weed seeds germinated and that it was not a huge issue.
Overall, he said that while Australian farmers were still getting to know how to get the best out of a disc seeding set-up, most were seeing the good outweighing the bad when the planter was teamed up with a dedicated zero-till farming system.
“There are many zero till technologies and they are constantly evolving with some significant improvements addressing some of the common limitations.”
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