"The beauty of cover cropping in
central Queensland": brothers
Alan and David Storey inspect the
trial on their property near
Emerald.
Photo by Rebecca Thyer.
Central Queensland's erratic rainfall prefaces much of the thinking on Alan and David Storey's 4450-hectare property near Emerald. The brothers crop in a region where 100 millimetres can fall in an hour, and rainfall periods can change from year to year.
"January to March is normally our wettest time," Alan says. "But in 2005 the wettest month was October and this year it's been June. So when it does rain we need to capture it."
This moisture-management challenge kick-started their involvement with the Central Queensland Sustainable Farming Systems (CQSFS) project, a joint venture between the Queensland Department of Primary Industries and Fisheries (DPI&F) and the GRDC. For the past 10 years, the CQSFS project has run trials on 200ha of the Storeys' farm.
David says the first one examined controlled-traffic farming and proved invaluable: "One of the first things we changed was the direction of our rows. We used to go round and round inside our contour bays. Now we have zero overlap, improved efficiency and more cropping opportunities. We learnt a lot from those trials."
The latest trial explored the costs and benefits of using wheat as a cover crop. Ground cover protects the soil surface from raindrop impact, improves water infiltration and decreases run-off and erosion.
Trials in southern Queensland have demonstrated benefits from using millet as a cover crop during a long fallow in a wheat-dominant farming system. The farming system in central Queensland is, however, more dominated by sorghum so it is winter cover that growers seek.
The DPI&F's Brendan Lynch, who works in the CQSFS project, says much of the central highlands plants sorghum in a skip-row configuration - where every third row in a one-metre system is skipped, creating two-metre-wide spaces and minimal ground cover. So the project explored whether a wheat cover crop would provide greater rainfall infiltration, particularly in spring, and make up for the soil water used by the wheat.
Although cover cropping was the main objective, sufficient rain meant the Storeys harvested the wheat. "That's the beauty of cover cropping in central Queensland," Brendan says. "Wheat can be planted for cover on minimal moisture, but depending on rainfall during the season, it can be taken through to harvest, sprayed out or left to die."
The CQSFS group's experiments with the Storeys will run for at least three more years.
Editor's Note: First published in the September - October 2007 issue of GRDC's Ground Cover (Issue 70). For permission to reproduce this article please contact GRDC.
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