Scenario 3 - Mallee Sustainable Farming

Development Phase

Intermediate Moderate Phase

Water Salinity Level

Low to Medium Salinity

Key Comments

While scalded areas are relatively small and topsoils at a less toxic stage, full restoration is possible provided immediate steps are taken to stop the excess water flows.

Discharge Zone Management

There are 3 paths that can be taken on the discharge zone, depending on the site situation and the farmers management preferences.

One option is to establish puccinellia / tall wheat grass on developing bare patches to maintain perennial cover and restore topsoil health within a few years. This will be dependent on reducing the flow of water into the seep zone to lower or dry out the perched water table. The area can be maintained for permanent cover and grazing, or turned back to crop production once topsoil is back to health.

Saltland Pasture Manual

A second option that may be more suited for continuous croppers, before the scald areas are too large, is to place 15cm of sand and straw on the bare areas prior to seeding, to achieve good crop germination and growth over the discharge area. However, this should only be done a high water use option is actively lowering the water table, such as a strip of lucerne around the seep perimeter. Otherwise, the capillary rise will continue bring salt to the surface and salinise the sand layer, nullifying any positive impacts of you earlier efforts. If this happens then it may be better to take the salt tolerant pasture establishment option.

A third option is to concentrate on utilising the excess water in the discharge seep area by permanently filling it with saltbush and salt tolerant pastures, without trying to intercept the flow of water into these areas. This is more suited to livestock farmers and its success will depend on the catchment area being small enough as to not overwhelm the water use created in the discharge area, otherwise the degradation will continue to spread. It is best to seed the area first with a mix of puccinellia, tall wheat grass and messina just prior to planting the salt bush rows. The spacing of salt bush rows may depend on your own preferences for ease of livestock management within the area.

Interception Zone Management

Sow lucerne in a targeted strip of about 20m wide between the discharge and recharge zones, as close as possible to the affected area to intercept lateral water flows. Larger lucerne plantings over the sandy recharge areas can be challenging, but if success and suits the farming system, then will more rapidly dry out the perched water table in the discharge zone. Maintain lucerne and crop through it if required.

Planting rows of local native trees to intercept flows and reduce water tables can be effective once they are well established, but this may not suit your farming systems and machinery operations, unless they fit along an existing fence-line for minimal impact.

Recharge Zone Management

Any deep sand amelioration with ripping, spading, delving, claying and the mixing in of manures or other organic matter etc, resulting in higher water retention and plant water utilisation will have a positive impact on reducing recharge, but will not have as dramatic affect as the water interception achieved with deep rooted perennials.

If it works for your farming system and paddock and you get a season with favorable conditions, then establishing lucerne over a larger portion of the recharge zone will significantly increase the rate at which the perched water table dries up and ceases to be affected by high rainfall periods and events.