GENERALLY, the favoured plan is to handle stubbles at harvest and cut low.
It is a management practice to enhance spray deposition on weeds and virtually eliminate blockages of seeding bars.
But when you’ve just experienced a bumper crop, things change.
The priority is to get the crop in the bin as quickly as you can, so you cut high with the intention of handling high stubble loads later, probably with the proverbial ‘Redhead’.
That’s the scenario on Robert Sewell’s farm at Wongan Hills, except he has ‘fire-breaked’ high residue paddocks with a Bednar Swifterdisc.
Yes he will drop a match this year but only because of the high cereal residue levels which would cost too much to manage by discing-in and/or applying nitrogen to break down the stubbles.
In a normal year (most years) he expects the Swifterdisc to do all the work, to chop and incorporate stubbles and to build organic matter faster than just leaving the stubble on top of the ground.
But this year farm manager Brad West has used the Swifterdisc to create fire breaks, trashing in twice to achieve the desire result.
He also trialled a Bednar Terraland chisel plough (ripper) – purchased seven weeks ago – on one of the runs and will return later with the Swifterdisc to level out the soil in preparation for seeding.
Mr Sewell bought the Swifterdisc last year primarily to manage thick cereal stubbles, improve efficacy of pre-emergent chemicals and achieve good mixing of ameliorants, mainly lime, in the top 120 millimetres of the soil.
“The job it does is really good and because it mixes in all the stubbles about 95 per cent of the weeds are plainly exposed to be hit by chemical,” he said.
“You also don’t get any movement of the soil because the packers leave a corrugated pattern which not only encourages water harvesting, it slows the wind.
“You get a bit of dust lifting but the soil stays intact.”
Last year the Swifterdisc was used over 3400 hectares and according to Mr West, “it did the job we wanted it to do”.
“I was worried it might stir up the ryegrass too much but where we used the Swifterdisc it turned out they were some of our cleanest paddocks,” he said.
“So obviously the pre-ems got to their targets.”
Last year the Swifterdisc also was used to incorporate potash and lime and some urea.
The latter, used at about 100 kilograms a hectare, was trashed in with canola stubble with the idea of breaking down the stubbles quicker and providing a residual benefit for a following cereal crop.
“It was a trial to assess the theory but we haven’t had any summer rain so at this stage it still remains a theory,” Mr West said.
This year the plan is to use the Swifterdisc over lupins and canola (after smashing canola stubbles with a Stubble Cruncher) for seedbed preparation and access cereal paddocks on an as-needed basis.
According to Swifterdisc distributor Grant Borgward, the Swifterdisc XE12400 is designed with a working width of 12.4 metres (which can match controlled traffic systems), is a three row unit with leading counter-facing discs on the front two rows followed by a V-ring roller.
Large central tyres work in conjunction with dual wheels on each wing to provide floatation across the front of the bar to prevent the bar from digging-in, particularly in sandy conditions.
This is further accommodated by using the hydraulics to place the bar in ‘float mode’ for ground-following travel.
The discs are aggressive “A-type’ design with more cutting edges than a scallop or plain disc, meaning trash residue is chopped to a small size.
These 520mm discs will also incorporate lime and stubble to a depth of 120mm, assisting freshly-applied lime to react quicker against low pH soils.
“The action of the Swifterdisc also makes it a valuable tool for straight incorporation of clay or gypsum,” Mr Borgward said.
The cultivation effect also provides pathways for plant roots to access moisture, while the V-ring roller knocks down soil clods, provides a level seed bed, incorporating smaller residues and locks in moisture by firming the surface.
The latter effect is important to prevent any capillary action of subsoil moisture being evaporated before seeding.
And the resultant hill-valley pattern of the roller dramatically reduces wind and water erosion while able to harvest any moisture from rain or heavy dews.
More information: Grant Borgward 0428 816 701.
