Pasture recovery after drought and fire

After significant rainfall in drought or fire affected areas this is a good time to think about getting pastures growing again. If areas have been in drought for more than two years have pastures thinned out and those plants remaining have depleted resilience, which requires care.

Early summer rainfall often grows a good crop of weeds rather than pasture for stock, especially if there is inadequate follow-up rain. Each paddock has varying pasture history and different plant species so each should be looked at individually and treated accordingly.

Fire affected Kikuyu paddocks in East Gippsland respond very well to rainfall events. These Kikuyu paddocks can be grazed or used as a sacrifice paddocks without any long-term damage. Kikuyu will offer very little winter feed, so over-sowing these paddocks with 10 to 15 kg / ha of a short rotation ryegrass in mid-March will give the farm some valuable winter feed.

In the high country native perennial pasture, species such as Wallaby grass (Rytidosperma spp.), Redgrass (Bothriochloa macra), Kangaroo grass (Themeda triandra) and the valuable Weeping grass (Microlaena stripoides) are resilient to both drought and fire. After these events, these species will re-establish over time but need a rest period to fully recover and increase their bulk, allowing for ground cover to re-establish.

Native species often grow on the steeper and often difficult to manage soils, or the lighter soils nearer to the coast. These soils are more vulnerable and need protection from wind or water erosion while regeneration occurs. Regeneration and recruitment are vital in native pasture paddocks as these paddocks are often inaccessible for resowing, plus the current plants have adapted over a long period and are well-suited to these soils.

Take time to assess the plant density within the pasture, even a plant density of 10 to 15 perennial grass plants per square metre will be enough to re-establish a native perennial pasture. This does not mean you cannot graze these paddocks, but you may have a lower stocking rate or choose to use rotational grazing for the next couple of years until native pastures are back to full strength.

Improved perennial pasture paddocks previously sown to Ryegrass, Phalaris, Cocksfoot or fescues will need to be assessed a couple of weeks after substantial rainfall, or after the autumn beak, to determine the density of plants and the vigour of their growth. Phalaris and Cocksfoot are surprisingly very drought and fire tolerant compared to ryegrass, so don’t under-estimate the ability of Phalaris and Cocksfoot to recover.

Assessing plant populations are important, to determine the best option for pasture recovery.  Depending on the species and the number of viable plants per square metre decisions can be made to either re-sow, over-sow or rest the pasture to regain the plant density that you require.  A pasture with 20 plus perennial pasture grass plants per square metre will be able to regenerate into a productive pasture given favourable conditions. Weed incursion is also expected but can be managed with selective herbicides after the autumn break.

Perennial clover pastures can survive cool to moderate fire and drought, depending on the severity of the event and some clover species have hard seed that will remain in the soil for many months, and recruit over time. Annual clovers such as sub clover will have viable seed buried in the soil and will germinate following drought or a cool to mild burn, providing the soil has not been subject to a very hot burn.

Annual pastures that rely on seed set from the spring will be worst affected, due to the loss of seed and the weed incursion into the bare spaces in the pasture, therefore be prepared to reseed once the autumn break arrives. Alternatively, these annual pasture paddocks could be sown for winter fodder crops or grain crops. Where extensive fencing has been lost and it is difficult to give pastures the rest they require, farmers should consider temporary fencing such as electric fending, or removal of stock on agistment or establishing a sacrifice paddock or stock containment area. Continuing to feed hay for a few weeks in a confined area will reduce grazing pressure on vulnerable pastures and will greatly assist in pasture recovery.

Details on how to build and manage stock containment areas is available from Agriculture Victoria offices or phone 136 186.

Page last updated: 23 Dec 2021