Mallee seeps
Working together with Eyre Peninsula farmers to manage mallee seeps
Mallee seeps are presenting Eyre Peninsula farmers with a challenge to overcome. Many farmers from WA to Victoria’s Mallee region now face the threat of permanent loss of productive farming land to Mallee seeps.
The Eyre Peninsula Landscape Board is providing support to farmers through focusing on overcoming the rising degradation of Mallee seeps on Eyre Peninsula.
The initial two years of the project was funded by the Australian Government’s National Landcare Program with the current 12-month project extension funded by the Board.
Mallee seeps expert, Farming Systems Consultant Chris McDonough from Insight Extension for Agriculture, has been leading the local trials.
Read this update from Chris at the end of 2021 on how the Mallee seeps interventions are working on each site so far.
What is a Mallee seep?
A Mallee seep is an area affected by a localised perched water table that brings water and salt to the surface soil layers that can result in surface ponding and bare saline scalding over time.
Mallee seeps generally begin when too much fresh water is present in the soil. The soil saturation leads to salinisation and land degradation if no management actions are taken. The issue for farmers is that soil health declines to the point that it no longer functions to support life. This project seeks to document the process of assessing a paddock with seep issues, explain where to concentrate efforts for remediation and visually show the effects of managing the area.
“Mallee seeps are a growing issue on the Eyre Peninsula, generally developing as perched water tables above tight clay layers, forming below deep sandy areas that are collecting excess water in localised catchment areas,” explains Dr Chris McDonough.
“They differ from the large scale highly saline creek-line systems that can’t readily be fixed individually by farmers. However, if left unmanaged, mallee seeps can rapidly spread causing water logging, increasing surface salinity and large, unproductive bare scalds.”
A farmer’s bottom line is affected by mallee seeps, the paddock is changed and productivity is affected. Ways to work with mallee seeps to lessen their impact in the paddock have been summarised by Dr Chris McDonough below.
They key to managing and restoring Mallee seep areas is to establish living soil cover over bare ground and to target high water-use strategies to reduce perched water tables. Read this case study from a Lock farmer about how he's been able to manage seeps.
Applying strategic management can result in:
- stopping the spread of the degradation;
- achieving good soil cover and grazing; and
- restoration back to full crop production, in some cases.
However this will depend greatly on how severe the seep scald has become at the time of applying intervention strategies - early identification and thoughtful action is the key to achieving optimal outcomes in Mallee seep management.
The project
The project is trialling management options suited to both mixed farmers and cropping-only farming systems to explore remedial options. The objective is to slow the increase in unproductive saline land in farming systems where farmers apply highly productive cropping techniques that increase paddock water use efficiency through the effective control of summer weeds.
Some of the methods being used to reduce the unproductive mallee seep areas include planting strategic strips of Lucerne up slope of the mallee seep, establishing puccinellia on the seep to slow osmosis, adding sand layers to improve saline scalded topsoils and pumping water out of the seep to use elsewhere on-farm.
Read this project summary from the first year of the project.
Resources for farmers
A series of videos are in the process of being developed to outline Mallee seep management options.
Video #1 - Creek-line salinity identification and management
Creek-line salinity is different to Mallee seeps but important to identify and manage to avoid spread into paddocks. Farming Systems Consultant Dr Chris McDonough explains how to identify creek-line salinity and outlines the management strategies of planting salt-tolerant trees and saltbush.
This video has also been included within the Mallee Seeps Decision Tree which is an interactive on-line guide to all aspects of Mallee seeps management.
Video #2 - Fixing a Mallee seep with Lucerne and Puccinellia
This video shows how quickly a growing Mallee seep scald can be turned back to production using strategic lucerne plantings and puccinellia. It includes footage and results from our trial on a Kimba farm.
Video #3 - Bringing a large recent bare scald back to life
See how a bare scald at Rudall now has cover with puccinellia successfully growing to help stop the seep spreading, improve soil and stop soil accumulating on the surface. Lucerne was also planted but wasn’t as successful yet. Chris McDonough explains what actions they will take to get lucerne to grow, which will help bring the land back to full agricultural production.
Video #4 - Fixing a developing seep before it becomes a scald
A trial site on a farm at Lock has come back to life from a developing Mallee seeps scald. The developing scald area had degraded over a few years – from being a noticeably wet spot in the paddock to not being productive at all. Watch how the trial project has progressed from a spreading scald to rehabilitated land that will be used for production again.
Ways to get involved
Farmers will be invited to see the trials sites near Kimba, Rudall and Lock throughout the project.
If you would like to be kept informed about the trial demonstrations and other project activities, you can contact:
Team Leader Landscape Operations - East, Tim Breuer (in Whyalla)
Ph: 0488 000 481
Email: timothy.breuer@sa.gov.au
Regional Agricultural Landcare Facilitator, Amy Wright (in Kimba)
Ph: 0467 004 555
Email: ralf@airep.com.au
Mallee seeps resources
The following resources provide more general information about mallee seeps:
- Listen to Dr Chris McDonough speaking in August 2020 about mallee seep trials in SA on ABC radio’s Country Hour (interview at 16.30)
- A GRDC update paper from Dr Chris McDonough, focusing on ‘soaks are seeping across the Mallee – what can be done about it?’
- Guide to using the Data Farming application for Satellite NDVI imaging to assist in identifying and managing Mallee seep threats.
Mallee Sustainable Farming (MSF) brings together farmers and researchers to build more efficient, profitable and sustainable farming businesses in the low-rainfall Mallee region across New South Wales, Victoria and South Australia. Their website is a useful resource including details of current projects.
Keep up-to-date
Find us on Twitter twitter.com/EPLandscapeSA and on Facebook at facebook.com/EPLandscapeSA. You can also subscribe to our quarterly newsletter which provides updates on all our projects.
