Mallee Farmers Reveal Seeps Impact
A report investigating the impact of seeps on farm land across the Mallee in Victoria and South Australia has confirmed that degradation caused by the fast growing emergence of high saline seeps could cost the region $10 million in lost production each year.
The survey found seeps are becoming a significant problem for a large number of Mallee growers.
Seeps are occurring in the Mallee landscape after rain water drains down through the sandy dune until it strikes the clay layer beneath.
This then exits at the base of the dune creating a seep.
While this area of higher soil moisture can provide some initial productivity boosts, over time the seep will draw salinity and eventually render that part of the paddock economically unviable.
Survey Coordinator Chris McDonough says Mallee farmers reported that the seeps were getting worse over the last ten years with changes to farming systems including spraying out deep rooted summer weeds allowing more moisture to enter the dune the most likely cause.
The Mallee Sustainable Farming survey estimates seeps could already be directly affecting as many as 250 Mallee farmers.
‘A few farmers have tried managing their seeps by planting some lucerne or strategic tree planting, mostly to mixed success. The one consistent message revealed by the survey was the desperate need for extensive local applied research to find viable solutions.’
He says the survey looked at when Mallee farmers first noticed seeps appearing, possible causes and how effective are current control methods.
In terms of actual land currently affected, the Mallee Sustainable Farming survey revealed an average of 9ha per farm impacted by a seep for an estimated total across the Mallee of 2250ha.
Mr McDonough says based on the rapid emergence of seeps during the last ten years, left uncontrolled the area of seeps affected land in the Mallee could potentially grow to 20,000ha over the next decade.
Losing that productive farm land, which might otherwise have yielded an average of 1.7t/ha @ $250/t along with the cost of lost grazing means a loss to the Mallee of $10million/year.
Image Source: Agtrader