LUCERNE establishment and chicken manure spading trials have been implemented to combat the ongoing problem of dune seeps in the Mallee region.
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Mallee seeps are often found in low-lying areas adjacent to sand dunes and have recently been discovered developing in mid-slopes.
Seeps begin as wet areas in paddocks producing good crops and cause the land to become unproductive as water draws salt to the surface and evaporates, causing salinity.
Natural Resources Management SA Murray-Darling Basin team leader – land management Bernadette Lawson and her project team have been working with farming groups to find agronomic and environmental solutions to manage seeps and bring land back into production.
"Once we've got an understanding of the processes we want to identify the options that fit into the farm enterprise, which can utilise that water to improve productivity and stop seeps spreading," she said.
Ms Lawson said the number of seeps reported by farmers had risen sharply in recent years.
“It has taken them a while to manifest into the problem they are. They take up large areas of productive land," she said. “It’s the best producing land because Mallee seeps are caused by a perched water table, which accumulates below the ground upon Blanchetown clay, which has very low permeability."
Water cannot move down through the heavy clay so moves across the landscape and discharges where the water table reaches the soil surface.
The project team established trials, with the major focus to intercept water before it reached a low point in the landscape.
Trials included lucerne hay establishment at Kevin, Geoff and Rodney Bond's Mannum property, which showed promising results.
Trials consultant Chris McDonough said 19 hectares of lucerne were established on a sandy rise adjacent to a seep and cut for hay, with this area less likely to contribute to future seep recharge.
A chicken manure spading trial on non-wetting sand adjacent to a seep on a Karoonda property also produced positive results, with barley yields increasing significantly in the spaded area.
Mr McDonough said initial economics suggested treatments were affordable, with costs recoverable in the short-term.
Ms Lawson said the trials were encouraging and the sites will be monitored to assess long-term effects.
"We have enough information to identify options, agronomic or environmental, to utilise that excess water in the landscape," she said.
