Scorched soils need time and gentle rain
GroundCover™ Issue: 56
Drifts of valuable topsoil heaped up beside roadsides are a painful sight for Eyre Peninsula farmers rebuilding their farms after January"s bushfires, reports Rebecca Thyer
[Photos by Rebecca Thyer:
(Left) Burnt out: Edillilie Landcare Group member David Giddings
lost a six-month old header in the fire.
(Right): topsoil heaped up along the roadside.]
Edillilie is a proud farming district with an impressive track record for innovation and professional land management. Its difficult soils and heavy winter rainfall can make cropping a hard task, although it is a challenge the district"s growers have risen to.
It is a progressive district, where minimum tillage and no-till are the norm.
However, in the aftermath of a devastating bushfire in January this year, the district"s farmers are facing their greatest challenge in many years, drawing on every bit of accumulated knowledge to rebuild their farms from the ground up - literally. Their carefully managed soils have simply blown away in the bare, blackened terrain left by the fire.
In April the GRDC conferred a "special award" on the Edillilie Landcare Group in the annual grower group awards to help the group rebuild its resources.
Group chairman Shane Nelligan says the district"s soils are acidic, non-wetting, waterlogging and have sodic subsoil. "While we receive up to 380 millimetres in the growing season, we only achieve 40 to 60 per cent water-use efficiency."
Soil in Edillilie, 50 kilometres north of Port Lincoln, is duplex and consists of clay subsoil incorporated into sandy topsoil, similar to soils found in southern WA.
Minimum tillage is the norm for the area, which is sown predominately to wheat, barley, canola and lupins. Stubble normally protects the sandy topsoil from drifting, but all of that was burnt off.
To stop soil erosion, many in the group have been delving, a process where a ripper digs into the ground, bringing the clay subsoil to the surface. The heavier clay stops the drift and also helps non-wetting soils. While delving will help initially, the problem could continue if the season is dry, and drifting sand could further damage crops at emergence and early growth stages.
Mr Nelligan says the immediate prospects for recovery depend heavily on constant rain: "However, with little or no topsoil left, the fire has also left us prone to water erosion." He says the area"s claybased soil is not a good water absorber.
Soil erosion is not the only challenge facing growers recovering from the fire. They have lost stock, houses, sheds and equipment. All fencing in an area covering about 80,000 hectares was destroyed.
Group member Peter Treloar, a GRDC Nuffield Scholar, says that delving and fencing have been two of the most immediate priorities. "Replacing boundary fences has been a massive task."
The scale of the fencing work is evident all around the peninsula. Everywhere you look, new fencing has been erected or is in the process of going up.
Diminishing fodder reserves are another concern. In an ironic twist, many growers had planned to join the GRDC"s Grain & Graze program this year to help them better manage the mix of cropping and livestock.
Mr Nelligan says that while pastures do not have a huge role to play within the group, it is still important to make better use of them. "It spreads the risk when grain prices fluctuate ... and lower grain prices and higher sheep prices have naturally fuelled our interest in pasture production."
In the past the group has undertaken numerous trials to better understand the district"s soil, as other Eyre Peninsula trials are often not relevant to Edillilie"s soils. "We wanted to have local knowledge to get local results," says Mr Treloar. "Usually we have to look to southern WA where the soils are similar to here."
The group began its local knowledge quest in 2000 when it leased 20ha for a water-efficiency trial, which highlighted the possible role of nitrogen in pasture improvement.
The trial also raised the possibility of growing lucerne, a crop the group did not previously think would take to their clay-based soils. However, lucerne roots did penetrate the subsoil, and the crop is now starting to be grown.
Trials have always been successful enough to make a profit, ensuring that other group activities such as annual field days and "sticky-beak" days, held every few months, are possible.
The group also experimented with summer crops, including sunflowers, sorghum and corn, with the aim of drying out the soil to help reduce waterlogging in the next season"s crop, says Mr Nelligan.
"It had varying degrees of success," he says. "It was successful in drying out the land, but we didn"t make any money from them, mainly because we don"t get enough summer rain. "It was a wet winter last year, so we thought there"d be enough water in the ground to grow a summer crop, but it just didn"t take. Our soils have a poor water-holding capacity and still need a spring rain."
Most of what the group grows is exported, which makes sense in an area serviced by Port Lincoln, the only port in SA capable of taking fully loaded Panamax class vessels.
While the group is in "semi-recess" at the moment, it still plans to get involved with Grain and Graze later this year, becoming more heavily involved next year. It also hopes to take a study tour to WA in 2006 to see how growers there make the most out of acidic soil.
For the moment however, the group is hectically preparing for this season. Volunteers - including the rural community and corporate companies such as National Australia Bank and Mitsubishi - that helped get farms back on track are starting to wind up.
But there is still a lot of work to be done.
Region North, South, West