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Precision cropping in limestone

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Corey Turnbull (left), Luke Turnbull and his son Johnny and Ramsay Bros director Hamish Ward.

Corey Turnbull (left), Luke Turnbull and his son Johnny and Ramsay Bros director Hamish Ward.

Kalpinnie, SA, farmers Corey and Luke Turnbull are under no illusions about the worth of a DBS.
The pair, who operate two 18.2 metre (60ft) DBS bars and two 18,000L Multistreams have been DBS owners for 15 years and remember seven years ago trading a 12.1m (40ft) DBS.
“It was eight years old and the money we got as a trade was the same amount that it cost us to buy the DBS in the first place,” Luke said.
The brothers crop more than 5000ha (12,500ac) of wheat and canola on heavy and loamy clay amid rocky limestone outcrops and at one stage owned a DBS and a bar from a competing brand.
“We copped a dry year and the difference between the DBS-sown crops and the other bar was 0.5t/ha which basically was the reason we traded it out of the farm for another DBS,” Luke said.
It has been what might be termed bracket creep since then, advancing from 12.1m working widths to 16.6m (55ft) to the existing 18.2m models, matched by incremental advances in Multistream models from 12,000L to 14,000L to the 18,000L units.
The ability of the DBS to handle the rough buffeting of rocky country while retaining precision seeding has been the main reasons why the brothers have stuck with the precision seeder.
Increases in crop yields provided the so-called proof of the pudding.
“There’s also the flexibility of being able to sow dry when conditions aren’t optimum but you want to keep going in the sowing window,” Luke said. “With the two rigs, we can get 250ha done with each rig in an 18 hour shift and up to 300ha if conditions are reasonable.
“We virtually wait for what we consider is the right window then go at it usually meaning we can finish in under five weeks.”
Working depth depends on rocks but generally the Turnbulls can get down 15-17cm (5-7in) sowing wheat and 11-12.5cm (4.5-5in) in canola.
“What we really notice is that in marginal country, the DBS gets through the stubbles so we can retain more moisture and the healthier germinations means roots can go chasing moisture,” Corey said. “You can see that (roots tapping into subsoil moisture) in tighter times because crops don’t pinch off.”
The brothers also are pleased with the Multistream’s performance, particularly metering canola.
“We sow canola about 2.2kg/ha which is as low as we want to go but there have been times when we went down to 1.5kg/ha and we did it comfortably,” Corey said.
“We get plenty of air which was one reason we fitted special diffusers to each tine so we can achieve gravity feed of seed.”

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Friday, October 16, 2015