'Olympics' sets new district practice

18 Dec, 2016 02:00 AM
A standard DBS set on 305mm row spacings and 90mm press wheels.
A standard DBS set on 305mm row spacings and 90mm press wheels.

THERE'S always a story behind a story.

In this case it concerns the Yuna Farm Improvement Group's (YFIG) 'Canola Seeding Olympics 2016'.

The objective was to employ four commonly-used bars seeding at three different depths (10 millimetre, 30mm, 50mm) to evaluate canola establishment in marginal moisture conditions.

The implication of the term 'Olympics', automatically focused attention of the trial on which bar performed the best job.

But that's not the story.

The whole idea of the trial was to push the boundaries of seeding depth to discover if there was a better way to establish canola, which typically is "scratched in" early with fingers crossed that it will rain.

The problem with that practice is the high risk of staggered germinations and the biggest problem facing growers is that they've only got one chance to spray for weeds because once the canola is out, and in the eloquent words of a YFIG committeeman, "it stuffs up your spray program".

That frustration was one of the main drivers of the canola trial.

The four bars were a Morris Contour 2 precision seeder, a standard Ausplow DBS, a modified DBS (with Stiletto boots and 130mm press wheels rather than 90mm) and a John Deere Air Hoe drill.

The results showed a statistically significant difference between machines in plant numbers, with the modified DBS ahead at all depths during three plant counts between June 13 and June 27.

YFIG organisers noted an exceptional plant establishment at the 10mm depth, almost certainly due to follow-up rain on June 4 - four days after seeding.

The aim was for 25 plants per square metre but the modified DBS row resulted in a plant count of more than 40 at 10mm, more than 35 at 30mm and more than 30 at 50mm.

But every machine established plant counts higher than 25.

While there were statistically significant differences (in plant counts) between seeding depths there was no statistical difference in yield between plots.

Agronomist Belinda Eastough explains:

"You would expect no difference in Roundup Ready hybrid canola yields once plant numbers exceed 20 plants/m2 in a low rainfall zone," she said.

"As DAFWA (Department of Agriculture and Food WA) research from 2014 showed, the RR hybrids have the capacity to adapt to low plant densities and yields tend to plateau around 20-25 plants/m2.

"The (YFIG) trial had very high field establishment at the 1cm seeding depth, however, due to the semi-indeterminant growth pattern of canola and the ability of RR hybrids to compensate, combined with excellent follow up rain three to four days after seeding and a very cool finish, there was no statistical difference in yield between treatments with 20 plants/m2 and treatments with 40 plants/m2."

The general agreement of YFIG members is that 30mm can now be considered the optimal depth to establish canola in the district.

At the 10mm depth, the risk remains of staggered germination and at 50mm, it was obvious the plants worked too hard to get out of the ground, losing yield potential.

Trial organiser and Yuna farmer Jason Batten emphasised the trial "was all about seedling establishment".

"Some people were surprised we established the trial on May 31, because everybody goes in earlier," he said.

"But the timing was more about getting members to attend because everybody was busy sowing in April.

"And the trial was never about yields, it was all about seedling establishment."

One of the spin-offs of employing four different bars was the resultant discussion on setting them up to sow at different depths.

DBS owner Ash Eastough said the trial had made him more comfortable to establish canola at 30mm.

"Most of us have very different soil types from one end of the farm to the other so it (trial) was to see how all four bars performed in the same soil type, in the same paddock, on the same day with the same seeding rate and try to achieve the same seeding depth," he said.

"Basically the trial is somewhere to start and we set the bars up the way we would set them up in our own paddocks.

"And at 50mm, everybody's bar was at a level where they had never seeded canola.

"After this trial, I will be more confident going into dry soil and seeding at 30mm."

According to Ash, the trial proved that any bar could be modified to achieve the right seeding depth.

"Seeding depth is the thing," he said.

"If you don't get that right it doesn't matter what else you do during the season.

"But the trial was not done to find out the best bar.

"It was done to help people look at how they set-up their bar in a way that achieves more plants per square metre, an opportunity to maybe reduce seeding rates and make more dollars.

"It's tweaking the one and two per centers."

Ken Wilson

Ken Wilson

is Farm Weekly's machinery writer


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