More water from less

More water from less

26 Nov 2009

As many farmers struggle with another year of dry seasons, new technology may significantly boost the soil’s capacity to provide water to plant roots – increasing crop yields by more than 60 per cent. 

more-waterThe system has been developed by agricultural scientists at La Trobe University in conjunction with soil scientists from the Victorian Department of Primary Industry. The project was funded by the Australian Research Council.

Called Subsoil Manuring, it incorporates high rates of organic nitrogen-rich material into the upper layers of dense clay subsoils. These soils, known as Sodosols, are widespread across grain-growing areas in south east and south west Australia.  

Dr Peter Sale, Head of the La Trobe University research team, said studies at two sites over three successive crops (between 2005 -2008) have found that while the technology is expensive, the rewards for sustainable crop production are also large.

The results of the technology have been demonstrated on wheat and canola crops in western Victoria. ‘For example, the incorporation of 20 tonnes per hectare of lucerne pellets at a depth of 30-40 cm at Ballan resulted in yield increases of more than 60 per cent for three successive crops,’ he said.

‘Research carried out in September 2009, more than four years after the organic material was incorporated in the subsoil, reveals that the tilth and aggregation in the clay subsoil has been substantially improved, indicating the method seems to have a long-lasting effect.’  

Dr Sale says the transformation of the subsoil’s physical and chemical properties is most likely due to an increase in bacterial and fungal activity in the subsoil.  

‘Improving the physical properties in the subsoil enables the crop roots to enter and explore the clay and extract soil water in these layers – water that would otherwise not have been available to the crop.’

The researchers are now evaluating the technology in a higher rainfall zone in south west Victoria. This is being done with the aid of funds from the Grains Research and Development Corporation.

Last week, at sites at Winchelsea and Derrinallum there were real differences in the colour of the crop. The control plots were yellow and mature, says Dr Sale, while those using the new technology of deep organic treatments were still green and growing.

‘This indicates that the crops on the deep organic plots are able to continue growing and extract water from the subsoil. Higher yields will certainly be expected from these plots.’

Other members of the research team are Dr Jaikirat Gill and Professor Caixian Tang from La Trobe University, and Dr Renick Peries from the Victorian Department of Primary Industry.

Dr Peter Sale

Phone: 03 9479 2188




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