Retrofit Discs for Duncan Seed Drills Solving Rocky No-Till Conditions in Fielding, NZ
In the rocky terrain of Fielding, New Zealand, dairy farmer John Ellis faced a serious seeding challenge, one commonly found with Duncan Seed Drills. After relocating to a new property riddled with embedded stones and hard ground, his once-reliable tyne drill became more of a problem than a solution. “The first season I did it with my tyne drill… a paddock full of stones appeared behind me,” John said. “It was horrible.”
Farmers Achieving better results with Ryan Discs on Duncan Seed Drills
John knew he had to adapt—but not by breaking the bank on a brand-new machine. Instead, he retrofitted his Duncan 3-metre drill with RYAN NT Retrofit Double Discs, turning it into a rock-ready disc seeder that could handle tough no-till conditions without sacrificing seed establishment.
John Ellis at his farm in Fielding, New Zealand
Finding Success with Duncan Seed Drills - Tyne Trouble to Disc Drill Dominance Conditions
The original Duncan seed drill tyne worked well on previous farms, but the rocky nature of his new paddocks quickly exposed its limitations. “We’re basically a no-till farm… there’s no turning the ground over where we are,” John explained. Pulling a tyne through that landscape “just lifted out stones” and left the field littered with obstacles.
Switching to a disc system offered immediate benefits: smoother operation, less soil disruption, and drastically reduced stone issues. “Hitting those [rocks] with the discs… had no damage whatsoever,” he said, describing rock sizes ranging from “cricket ball to rugby ball” common across the paddocks.
John Ellis' MK4 Renovator Duncan Seed Drill with RYAN NT Discs
An Affordable Retrofit That Works
Rather than investing in a new disc drill, John searched for retrofit options and discovered RYAN NT’s system designed specifically for Duncan seed drills. “We couldn’t find anything in New Zealand… they all wanted to sell me a new disc drill,” he explained. But the RYAN NT solution “was really what I wanted to do to my drill.”
The conversion process was straightforward. Once he got his bearings, John found that operating the converted drill was simpler and more efficient. “You’re basically running the same drill—just with a disc instead of a tyne. It was a lot easier to pull,” he noted.
John Ellis' MK4 Renovator Duncan Seed Drill with RYAN NT Discs
RYAN Discs on Duncan Seed Drills Equals Performance in the
Paddock
Despite it being his first season with the RYAN NT discs, John was quick to get the hang of his Duncan Seed Drill upgrade. “It took me half a paddock to get used to it… once I got it set up the way I wanted to, the discs were just cutting a slot down where the seed was going in,” he explained.
He typically drills between 8–10 km/h, finding the disc system offered smoother penetration and less slot disruption, especially important in his hard, stony soil. He also found no issues with mud, as the planting window was during dry conditions.
John Ellis explaining how you can barely see where the discs have run.
Ryan Discs on Duncan Seed Drills are Proving themselves on Diverse Crops
John’s farm runs a variety of cropping programs including summer brassicas, winter kale, and autumn pastures. His kale crop was drilled before Christmas and was “well-established” with “no problem” in germination. “The plants were well established,” John said. He noted pulling a steel roller behind the drill helped retain ground moisture, supporting germination.
The discs also performed well in challenging conditions where rocks are embedded just under the surface. “With a tyne drill, they become part of the landscape. With discs, it might flick out the odd small rock, but it’s not as common,” he observed.
A rocky paddock on John's farm.
Trusted Among Other Farmers
John’s converted Duncan Seed drill has sparked curiosity among other local farmers. “I’ve had a bit of interest… mainly because Duncan is quite an established drill over here,” he said. His compact 3-metre drill suits his farm size, and the retrofit gives it new life in tough conditions.
John shwoing the size of the rocks he has to deal with when sowing.
Looking Ahead: Autumn Plantings and Trash Handling
Looking to the next planting season, John anticipates even more value from the Duncan Seed Drill disc setup. “It’ll come into its own again in the autumn when we have a bit of trash around—the discs will just fly through that,” he said, noting the system will reduce issues with weeds and trash interference.
John Ellis' MK4 Renovator Duncan Seed Drill
Additional Insights from the Field
While John has only had the Ryan discs on his Duncan Seed Drill for one season so far, he’s already noticed they open new opportunities for pasture management. In one paddock used for summer kale, he plans to overdrill with ryegrass and clover after the final grazing. Confident in the discs' ability to slice cleanly through any leftover stubble, he’s optimistic about a successful re-establishment without needing to disturb the soil again.
Learn More
Explore how RYAN NT can enhance your seeding equipment with solutions like Retrofit Discs:
Conclusion
John Ellis’ experience demonstrates the power of retrofitting over replacing. With RYAN NT Retrofit Discs, his Duncan seed drill now handles the rugged demands of his no-till dairy operation in Fielding, New Zealand—without digging up stones or sacrificing crop performance. For farmers facing similar rocky realities, John's story offers a clear alternative to expensive equipment upgrades.