Development Phase

Intermediate Moderate Phase

Water Salinity Level

High to Very High salinity

Key Comments

These sites can continue to deteriorate to larger bare saline scalds, depending on the size of the perched water table beneath. The strategy must be to stop any flow of rainfall recharge from entering the highly saline perched water table so that over time it may subside to a level lower than it can affect topsoils and crop growth. Swift action is necessary to limit the amount of salt rising and contaminating the top 50cm of rootzone soil that will greatly impede the process of rehabilitation back to production.

Discharge Zone Management

With high water salinity, these sites can deteriorate very quickly to large highly saline scalds. It is recommended that the salt tolerant puccinellia and tall wheat grass be sown into this area to establish permanent cover and utilise water before it brings salt to accumulate to highly toxic levels at the surface. This will buy some time to protect the site while the interception zone treatment to establish and begin to take effect. It is better to roughen the soil surface and waiting for a good salt leaching before sowing or spreading the puccinellia, as this will give the seed more opportunity to find suitable niches to establish in. Bare patches will tend to fill in over time, and time can be encouraged by cutting and spreading seed heads. Lucerne establishment on or immediately surrounding this discharge zone will have limited success due to high perched water table salinity.

Interception Zone Management

Sow lucerne in a targeted strip of about 20-30m wide at least 20-30m up the sandy rise, where the lucerne roots can access and intercept water of lower salinity before it reaches the discharge zone. Maintaining this lucerne strip long term will be vital, even if cropped through the growing season. If the water table is still found to be highly saline in this suggested mid-slope zone, then planting salt tolerant trees around the boundary of this emerging seep area may be the best option.
Planting rows of salt tolerant trees to intercept flows and reduce water tables can be effective once they become well established. However they may not suit your farming systems, unless they fit along an existing fence-line for minimal impact or you are prepared operate machinery around them.

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.

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