Treading lightly to restore native pasture after fire

Native pastures play an important role in livestock nutrition for some farmers, particularly those in the North East where the environment and landscape is well-suited to native species. For those farmers affected by the fires of 2019–20, restoring native pastures is an important step in the farm’s recovery.

There are about 1,000 native grass species in Australia; species that are well adapted to the country’s harsh and varying climate and low-fertility soils. As a result, there are situations and environments where native pastures can be a well-adapted, sustainable and suitable choice for livestock production.

Research shows that to restore native pastures you need to implement deferred grazing. While this is something most farmers do traditionally, it is particularly important to carry out this strategy after fire. Restoring native pastures will help maintain population density and avoid invasion by undesirable species such as onion grass, broadleaf weeds and annual grasses.

There are many deferred grazing regimes including optimised deferred grazing, short-term deferred grazing, long-term deferred grazing, timed grazing and strategic deferred grazing.

The aim of deferred grazing is to:

  • ensure ground cover remains about 70 per cent up to mid-January
  • increase native perennial plant density
  • reduce annual grass seed germination
  • increase perennial germination and seedling survival
  • increase root biomass down to 60cm
  • increase subsequent years herbage mass.

Optimised deferred grazing

Optimised deferred grazing is one of the most effective strategies to alter pasture composition and lift perennial grass population and production while suppressing annual grasses. This strategy requires a high stocking rate, with animals grazing dry and lower quality feed.

Care needs to be taken with the class of stock grazing these pastures to ensure their needs are met. Supplementary feeding may be required to meet nutritional requirements.

With optimised deferred grazing, the withholding time from grazing depends on the growth stage of the pasture plants, with grazing generally prevented from spring to late summer depending on seasonal variations.

The period of time that paddocks need to be rested for optimised deferred grazing will depend on the pasture growth stage and seasonal variation. Generally, this occurs in spring to late summer.

This deferred grazing starts after annual grass stems elongate, but before seed heads emerge so the growing points of undesirable annual plants can be effectively removed by close grazing. The completion of the paddock resting phase for this grazing strategy depends on pasture conditions of the desirable perennial grasses (seed set, growth and herbage on offer), which are generally ready for grazing from late summer to early autumn.

This strategy aims to reduce the amount of seed produced by annual grasses and alter pasture composition – lifting the proportion of perennials while suppressing the annual grasses.

To implement optimised deferred grazing, farmers need to have a clear understanding about pasture composition, growth stage, seasonal constraints and expected outcomes.

Optimised deferred grazing should be used when:

  • There is a reasonable amount of desirable perennial species (>20 per cent)
  • There is the capacity to intensively graze a paddock (adequate fencing and stock requirements).

Timing is crucial, as heavy grazing is required when most annual grass stems have elongated in late winter and early spring but before the seed heads emerge.

Deferred Grazing (DG) Quick Reference Guide

TypeAimMethodPost DG
Optimised

Increase perennial and suppress annual grasses (initial native grass composition greater than 20 per cent)

Graze pasture heavily when annual grass stems elongate and before seed heads emerge. Complete DG in late summer to early autumn

Rotational grazing using native grass leaf stage as a guide

Short-term

Use feed in summer while increasing soil seed reserve

Withhold grazing from mid spring (October) to mid summer (January)

Rotational grazing using native grass leaf stage as a guide

Long-term

Restore perennial plant density

Withhold grazing from mid spring (October) to autumn break

Rotational grazing using native grass leaf stage as a guide

Timed grazing

Restore plant density of very degraded native pasture (initial native grass composition less than 20 per cent)

Preferably withhold grazing in mid spring (October). Graze pasture after 120 to 130 days of resting, then repeat for at least a year

Rotational grazing using native grass leaf stage as a guide

Strategic grazing

Combine deferred grazing with weed and fertiliser management

Choose one of the DG strategies. Use the same rule of the DG

Rotational grazing with weed and fertiliser management based on recommendations

Page last updated: 02 Jun 2021