Sandplain farmers struggling with non-wetting soils, herbicide resistance and sub-soil acidity could have a new, old-fashioned tool to help alleviate all of these challenges.
Mouldboard ploughing has been trialled by the Department of Agriculture and Food in the Northern Agricultural Region for the past two seasons with impressive results.
These results will be profiled at its 2009 Agribusiness Crop Updates in Perth on 24-25 February and at later Regional Updates.
A mouldboard plough has a wedge shaped board fitted with skimmers to cut and invert surface soil, in this case to a depth of 25-30 centimetres.
Six large scale demonstration sites were cultivated using this method in the Mingenew area for wheat, canola and lupin crops in 2007-08.
The trials produced a 41pc increase in yields, on average, due to the use of mouldboard ploughing across all sites generated by reduced water repellence, cultivation and less competition from weeds.
Water droplet penetration tests showed three sites were extremely water repellent.
Weeds research officer Peter Newman said the water repellency was alleviated by inverting the soil with the mouldboard plough.
"The mouldboard plough simply brings up soil from depth that does not have the water repellency characteristic," Mr Newman said.
"In theory, soil microbes should degrade the wax that causes water repellency of the soil that is placed at depth by the mouldboard plough.
"However, further research is required to confirm this theory."
The results showed a 90-95pc reduction in weed emergence after a single cultivation with the mouldboard plough.
The mouldboard plough controls weeds by placing weed seeds to a depth from which they cannot emerge.
Mr Newman said it was important to leave weed seeds at depth for at least 10 years for the weed seeds to decay.
"There is little doubt a one-off inversion of sandy soil with a mouldboard plough every 10 to 15 years is going to be a very profitable and effective method of quickly decimating a seed bank of resistant weeds," he said.
The department is now exploring the possibility of using mouldboard ploughing to help bury lime to address sub-surface soil acidity.
While mouldboard ploughing is inconsistent with the rising interest minimum tillage cultivation practices, Mr Newman believes the results suggest it could have a place in sandplain farming systems.
"A one-off soil inversion in the right situation could be very useful," he said.
"It may not be the answer to all problems but it certainly addresses some of the greatest challenges facing this farming system."
* More information on this year's Agribusiness and Regional Crop Updates can be found at www.agric.wa.gov.au/cropupdates.
Regional Updates will be held on 27 February - Northam, 3 March - Merredin and Jerramungup, 4 March - Liebe Group in Buntine and Ravensthorpe, 5 March - Mingenew Irwin Group in Dongara, March 6 - Gearldton, March 9 - West Midlands Group in Badgingarra, 10 March - Hyden, 11 March - Corrigin, 12 March - Narrogin, 13 March - Katanning and 17 March - Esperance.