Probe into subsurface water management

Probe into subsurface water management

Grains
 Stirlings to Coast Farmers smart farms co-ordinator Philip Honey said there will be grower participation in the planning, development, monitoring and maintenance of the drainage installation trial sites.

Stirlings to Coast Farmers smart farms co-ordinator Philip Honey said there will be grower participation in the planning, development, monitoring and maintenance of the drainage installation trial sites.

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Project drills down into the return on investment from subsurface water management options for waterlogged areas.

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A PROJECT being run in Albany and Esperance over the next three years will drill down into the return on investment from subsurface water management options for waterlogged areas.

The Grains Research and Development Corporation (GRDC)-funded project will help growers make decisions about the installation of drainage to reduce the affects of waterlogging on crop production areas in order to increase overall farm profitability.

In Albany, the project is being led by Stirlings to Coast Farmers (SCF), while South Coast NRM is heading it up in Esperance.

SCF smart farms co-ordinator Philip Honey said there would be grower participation in the planning, development, monitoring and maintenance of the drainage installation trial sites.

"Data - cost of implementation/maintenance, water movement, establishment, biomass, yield, etc - from within the zone of influence of the drainage and outside this zone at each site will be collected over time," Mr Honey said.

"That will give growers a better understanding of the improvements in yield and time to return on investment at each site."

Waterlogging is a common problem within the south-west region of Western Australia, particularly in the wetter months of winter and typically occurs when rainfall exceeds the ability for soils to drain away soil moisture.

Under these conditions, the excess water within the root zone creates conditions without free oxygen and prevents the plant from performing gaseous exchange with the atmosphere or biological activities with the oxygen in the soil, air and water.

Mr Honey said left unmanaged, waterlogging could lead to soil structural decline and has the potential to create nutrient deficiencies and toxicities, cause root death or reduced plant growth, or worst case, result in the death of the plant.

"Overall, it has been estimated that about three million hectares of land within the South West agricultural region of WA has moderate to very-high susceptibility to waterlogging or inundation, which represented an estimated annual opportunity cost of $35 million between 2009/10 to 2013/14," he said.

"There are methods available that farming operations can utilise to minimise and mitigate against the affects of waterlogging, including the use of either surface water management or subsurface water management methods.

"Surface drainage/management options available to growers include options such as raised beds, evaporation basins and interceptor drains, while subsurface options include slotted pipe, mole drains and pumping option."

Unfortunately, the challenge with the implementation and adoption of some of these water management methods is that they often affect farming operations.

That could be due to potential reductions in machinery movements and productivity or simply due to the cost of implementing the drainage method.

Subsurface drainage methods are typically less invasive than surface management options and offer added benefits such as better trafficability without the loss of machine and operations productivity.

Mr Honey said the project had set an ambitious goal to be achieved by 2024

"We want to have 45 per cent of growers whose properties are affected by waterlogging to have a good understanding of the yield benefits and time to return on investment of installation of onfarm subsurface drainage and ability to implement onfarm," he said.

Mr Honey said as part of that, they ran a dedicated installation event which allowed growers to see subsurface drainage implemented onfarm and interact with installers.

Both SCF and South Coast NRM will be running workshops, covering the requirements of implementing a subsurface drainage solution - including contractor and site selection, drainage design options, installation techniques and subsurface drainage maintenance requirements.

The workshops will also give growers an understanding of the legislative agreements required when implementing subsurface drainage for the discharge of water, as well as an understanding of how to calculate the return on investment when implementing subsurface drainage solutions.

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