The trial pitted a Tobin Disc Drills Bullet disc machine set up on 30-centimetre spacings with a single-disc opener, rubber gauge wheel and trailing press wheels against an Auseeder Deep Blade System (DBS) on 25cm spacings with knife-points and press wheels and a no-tillage Shearer Scari-fier on 25cm spacings with Agmaster knife-points, boots and press wheels.

A 52-hectare paddock was sown to Wyalkatchem wheat for the trial, and with the season dry, it was sown into marginal moisture, about 25 to 30 millimetres deep.

The trial then compared yield data, collected by a yield monitor on the harvester, from the three machines over a range of soil types.

Author of the report, Simon Wallwork, of Corrigin, said the trial had found planting with a disc seeder could improve seed placement and trash flow, use less fuel and conserve more moisture compared with the tyne machines.

On the downside, the disc seeders were expensive to buy and maintain, and often not as safe when applying pre-emergent chemicals.

Mr Wallwork said the ability to work at high speed was the main benefit that encouraged farmers to invest in a disc seeding system.

The tyned machines were pulled at nine kilometres an hour, while the Bullet seeded at speeds between 16 km/h and 18 km/h.

Mr Wallwork said the DBS machine initially showed superior plant establishment, however, the Bullet was able to consistently place seed deep into moisture, despite its greater speed.

He said when compared on the same soils, yields were better from the disc machine on all soil types.

Director of Tobin Disc Drills, Noel Tobin, Forbes, who manufactures the Bullet planter, said the trial had proved what his company had always known.

“When we started making the machine in 2003 farmers laughed at us, because it was almost like saying you can now drive on the road at 200 km/h instead of 100 km/h,” he said.

Mr Tobin admitted it took some time to perfect the machine, but said it was now able to work on all soil types.

“The Bullet can reduce inputs such as fuel, labour and time,” he said.

The unit could plant at speeds of up to 25km/h, however this was limited by variables such as roughness of the ground, size of the air seeder cart and the size of the tractor pulling it.

One point Mr Wallwork made in his report was that farmers needed to decide if the efficiency of doubling the speed of sowing could outweigh the higher cost of the disc machine compared to the tyne machines.

Mr Tobin said the Bullet was not the cheapest, nor the dearest machine on the market and farmers had to consider the cost of inputs in the long-term.

What had happened was that the trial had shown that a disc machine could successfully establish a wheat crop at high speed.

Industry and Investment NSW district agronomist at Walgett, Myles Parker, said a number of disc machines were now in use in the district, but farmers around Walgett couldn’t survive using just a disc machine because they didn’t plant well into every condition.

“When conditions are right they can plant very fast and reasonably accurately, but if the ground is too wet or too dry, farmers seem to be going back to using tyne machines,” Mr Parker said.

“Most owners of disc machines also still have a narrow point machine, which can be used in any condition,” he said.

Source: farmonline.com.au