Steve puts tillage tools to good use
Tillage is not a dirty word, even for WA’s no-till farmers.
In the case of non-wetting soils, Department of Agriculture and Food Geraldton researcher Steve Davies said tillage tools could be put to good use.
The use of ploughing in no-till farming can help to build up stubble over several years, according to Dr Davies. He said spading to lift the wettable soils to the surface could result in better yields and set a thicker stubble bed.
Tillage tools such as spaders and mouldboard ploughs invert the soil to bring wetting soils to the surface.
“We are talking about using these tools on sandplains only, definitely not on loams or clays, which you would not want to damage,” Dr Davies said. “And we are talking once in every 10 to 15 years.
“We are not saying tillage every year by any means, that would be disastrous. It’s a one-off event to combat water repellence and weeds.”
To avoid wind erosion, Dr Davies said areas tilled would need to be seeded immediately.
Other methods of combating water-repellent soils include furrowing, soil wetting chemicals and claying.
“Furrow sowing can be an effective method of water harvesting, but it’s not always reliable with non-wetting soils and you still get yield variations,” Dr Davies said.
“The dry soil sits in those furrows but there is room for improvement, because it still has a place as a tool for non-wetting soils.”
Soil wetters — banded surfactants — was another tool that Dr Davies said was useful, but still unreliable.
He said claying was another useful tool for dry soils. “It has been tried extensively by many farmers,” he said. “It works but it is expensive.”
Bolgart farmer Trevor Syme has been spreading clay on his property at different rates since 1998, trialling different incorporation techniques.
Mr Syme has 3100 hectares of continuous crops in soil types ranging from red loams to deep white sands.
“Our non-wetting sand yields up to 1.5t/ha and that’s it. On our wettable soils, we get 3.5t/ha,” he said.
“Even in a good year, all the fertiliser gets leached and goes to waste through the sand.”
Over the years, Mr Syme said using stubble retention to combat water loss had helped, but clay had been the icing on the cake.
With a normal multi-spreader, he spreads around 100t/ha of clay.
“Sourcing and spreading clay can cost $700/ha,” he said. “It isn’t cheap, but it eventually pays for itself.”
In one trial, Mr Syme got one tonne more per hectare of canola in the clayed section of paddock.
“We didn’t think we could grow a profitable crop on some of the land, and so it was earmarked for tagasaste,” he said. “Now, I think I will get rid of all of the tagasaste.”
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