Simplifying stubble, cropping solutions

New gear gives some grunt to stubble management


Precision Agriculture & Machinery
Rob OConnor with his custom-made machinery combination designed to handle high stubble loads while simultaneously sowing the next crop. PHOTO Catherine Norwood

Rob OConnor with his custom-made machinery combination designed to handle high stubble loads while simultaneously sowing the next crop. PHOTO Catherine Norwood

Aa

Bulky stubble proving no obstacle to seeding systems for northern Tasmanian grower.

Aa

Not many farms have to deal with the stubble from an eight or nine-tonne per hectare wheat crop.

But in Tasmanias north-east it is an annual issue for Rob OConnor, general manager of the family-owned Benham Tasmania Company, on the South Esk River.

Heavy stubbles come with their own challenges the potential for fungal infections if left standing, or difficulties incorporating so much organic matter into the soil.

SEE ALSO:

It is an increasing problem in Tasmania - and other high-rainfall or irrigation areas - where growers are pushing crop production to yields of more than 12t/ha and leading some to resort to stubble burning.

At Benham, Rob has settled on a mechanical solution to high stubble loads, and one that lets him close the gap between harvesting one crop and sowing the next.

Ideally he would plant the same day if he could, but he aims for the same week.

To do this he has commissioned a new equipment combination: a single-pass disc plough, leveller, seeder and roller, custom-made by machinery manufacturer Delmade based in Westbury, Tasmania.

Rob says his previous gear came from Europe.

It was not quite the combination he wanted, and it did not have the robustness needed for local conditions.

We wanted to leave the ground a bit rougher," he says.

"Our soils are quite sandy and exposed to wind erosion if we get them too flat. And we need depth with the discs because of the stubble loads, and because we sow straight away."

Stretching six metres wide, the discs can cut through heavy stubbles and soil to a depth of 20 centimetres, with the leveller knocking down the clods before sowing and rolling.

It can travel up to nine kilometres an hour, but in thick stubbles, and given the depth of cultivation, may be limited to only 6km/h.

While other equipment may be faster, Rob says the combination, with one operator, is proving more efficient.

We wanted to leave the ground a bit rougher. Our soils are quite sandy and exposed to wind erosion if we get them too flat. And we need depth with the discs because of the stubble loads, and because we sow straight away - Tasmanian grower Rob O'Connor

In the past five years, Rob has simplified the cropping program at Benham, favouring ease-of-management, flexibility and repeatability in his operations.

He has instead expanded his broadacre cropping, which includes up to 900 hectares of irrigation and up to 1000 hectares of dryland cropping.

Irrigation work

With an average annual rainfall of 480 millimetres, it is on the drier side of farming in Tasmania.

But a substantial water allocation and on-farm water storages give Rob the ability to adapt to seasonal variability. He plans to double Benhams irrigation over the next 10 to 15 years.

He says that having control over water means being able to water through summer:

If we can get things in on time, and achieve a lot in a small window with the machinery we have, then we can manage our way through just about anything," he says.

The cropping program is based on wheat, barley and canola, double-cropping with fodder crops and spring cereals, followed by a pasture or another break crop, and then poppies.

The fodder crops are an opportunistic double-crop and selection depends on the timing of cereal harvest. Cereals include long-season winter wheats such as SQP Revenue (PBR) and Manning (PBR), or LongReach Kittyhawk (PBR) as the dominant spring wheat.

If we can get things in on time, and achieve a lot in a small window with the machinery we have, then we can manage our way through just about anything - Tasmanian grower Rob O'Connor

Rob says closing the time frame between harvest and planting is simply about maximising production.

Kale can equate to a tonne of fodder per hectare per week against the sowing date. So a delay of a week or two is huge, in terms of lost production," he says.

Fodder crops are used for Benhams own livestock and also for dairy cows on agistment. Crops include kale, pasja tillage radish, forage sorghum and lucerne, depending on the timing, rotation and soils.

Dryland cropping rotations are a standard wheat, wheat, canola, barley, dryland pasture program. Marginal soils remain sown to pasture for longer, but better soils will be put back into rotation more quickly.

Benham totals 19,500 hectares. Sixty per cent of the property is highland grazing and forestry, with 20,000 fine-wool Merinos. A breeding program over the past decade has led to an increase in micron size from 16 to 17 microns.

It is still in the fine range, but the ewes are stronger and able to produce prime lambs while also producing larger wool clips.

More information: Rob OConnor, rob@benham.com.au

Aa