Scalded paddocks could once again become productive and sustainable following the results of work with landholders in the catchments of the western region of northern NSW.

Many landholders are willing to have a go at restoring their scalded paddocks if the technical assistance is available, and results so far indicate it’s worth the time and effort. Scalded landscapes are difficult to characterise as a number of soil degradation processes are often occurring – a major reduction in vegetation cover and soil organic matter the most  common.

As the soil surface sets hard, most of the rainfall is lost via runoff or from moisture evaporated from ponded water, leaving little moisture for crop or pasture growth in an environment where rainfall is already a limiting resource. Establishment of pasture plants can also prove difficult because the thick crust that commonly forms on sodic (dispersive) soils can prevent seedling emergence.

In addition to the compaction caused from decades of set stocking by hard hoofed animals, raindrops affect the bare soil surface and pack surface crusts even tighter. This increases the rate of soil slaking which causes structured soil aggregates to break down or collapse into smaller fragments. Transient salinity can further limit or complicate the establishment of
crops and pastures across scalded paddocks and may be an issue when, over time, surface soil has been extensively eroded back to a naturally saline ‘B’ or subsoil horizon.

The many variables emphasise the importance of characterising the soil properties of each scalded paddock. Tests to determine pH, slaking and dispersion, soil texture and ECe (salinity) will help in determining the best management approach.

Management approaches that have met with varying success include fencing and rotational grazing, establishing suitable tropical grass pastures, building on existing native plant systems, saltbush alleys or corridors, horseshoe water ponds, deep ripping and treatment with gypsum. Evidence suggests that fencing and controlled rotational grazing can be a highly effective approach to improving production and sustainability of scalded paddocks.

Resting for a period will allow native grass species such as Mitchell grass and shrub species including Bluebushes and Saltbushes to establish, building up organic matter and creating small niches for further plant establishment. Some form of soil disturbance which breaks up the crusted surface of scalded paddocks may accelerate plant establishment.

Saltbush alleys alternating with corridors of native or improved pasture may be a viable option to rehabilitate sites as many species are known to persist in hostile soil environments. IIn addition to boosting the forage value of a system, they offer protection and organic matter contribution to scalded soils that are prone to erosion.

Contact Lachlan Rowling, Tamworth, 02 6763 1166.