AFTER a successful first year and as a result of the vested interest of a local farmer, a subsurface drainage project in the Albany port zone has been expanded.
Stirlings to Coast Farmers (SCF) started the project, with funding from the Grains Research and Development Corporations (GRDC), last year to help growers make informed decisions about installing drainage to reduce the impacts of waterlogging on crop production areas and increase overall farm profitability.
While the final results from the first year were still being analysed, initial evidence showed a noticeable improvement in trafficability on the paddocks with subsurface drainage installed, despite 748 millimetres of rain falling on the Cranbrook farm, owned by the Preston family, causing mass waterlogging.
SCF smart farms co-ordinator Phillip Honey said 2021 ended up being a 99th percentile year for the Prestons and the difference between the sections with subsurface drainage and the control area, which was undrained, was chalk and cheese.
"There were times throughout the season where we put our gumboots on and struggled to walk through the paddock," Mr Honey said.
"You would walk through the control areas and get foot logged in gumboots, but when you crossed to the sections which were drained, you were almost standing on solid ground, so the difference was astronomical.
"We also did some initial plant counts and when we were looking at tiller counts, there was a 30 per cent increase in the drained compared to the control, so you know you're going to be better off."
The Prestons were not the only ones to cop ridiculous amounts of rain in 2021, with Mt Barker farmer Kieran Allison receiving 830mm for the year, close to 300mm above average.
While waterlogging is nothing new for the area, from 13 weeks from May onwards last year, he was forced to do his farming via helicopter.
"I got the crop in early, having started seeding on March 23 and we were done by April 28, so my last radish spray was just before it got really wet on cereals," Mr Allison said.
"After that, all of my fungicides, growth regulators and fertiliser were applied by helicopter for the rest of the season.
"I didn't want to wreck the paddocks knowing that it was already wet heading into winter - the deeper the ruts go, the more erosion you cause and I wanted to minimise that."
Wanting to go hard on a solution, Mr Allison has installed about 10 kilometres of subsurface drainage, with the SCF and GRDC project to look after the analysis of its impact and the return on investment (ROI) it offers.
He normally does a surface drainage program but wanted to maximise machine efficiency on the paddocks.
"I do about $150,000 of surface drainage every year and to do the subsurface instead for the 10km is a bit over $200,000, so we haven't gone from zero to 100 with it by any means," Mr Allison said,
"With a controlled traffic program, having subsurface drainage means I can keep driving my lines which will increase productivity in those areas."
For SCF, the key motivation behind supporting Mr Allison's project was that it offered them a second data set to be able to answer the million dollar question - is the about $13,000 per kilometre spend on subsurface drainage worth it in terms of ROI?
However, when it comes to ROI, Mr Honey said there was more to subsurface drainage than just waterlogging.
"The alternative option of surface drainage means there are drains on top of the paddock, which reduces trafficability which leads to overlap and reductions in productivity," he said.
"We'll be looking at a range of factors including yield analysis, water quality, soil sampling, plant analysis and weed burden.
"That last point is a big one because what we saw at the Prestons' was that where it was drained, there was a lot less weeds."
The biggest real difference between the two trial sites at Cranbrook and Mt Barker is their soil type.
At the Prestons, there's about 30 centimetres of sand before clay so when there was a full profile, it didn't take long for it to drain and fill back up.
Whereas Mr Allison has a fair bit more sand and gravel before getting to the clay.
As part of the project, which will run until the end of 2024, SCF will also have an in-depth look at characterising that soil and how much the pipes effectively extract water from those different soil types.
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