Most fires have a major effect on pastures, as do long periods of drought.
Fire and drought change pastures in different ways according to a number of different factors: the intensity of the fire; the pasture species; the fertility of the soil; the time of the autumn break; and the following rains.
Unfortunately most weeds, especially perennial, survive fire and drought very well. They are also the first plants to recover and they may be prominent, due to lack of competition from preferred pasture species.
Drought or fire may cause large areas of perennial pastures to have thinned out depending on severity or intensity. Some pastures are resilient and may recover once good soil moisture conditions return.
Traditionally, phalaris has been the outstanding survivor, followed by cocksfoot, fescue and then ryegrass. Young perennial plants without well established root systems are most vulnerable. Grasses with growing points below the surface will survive best. A very hot fire will usually kill all perennial grasses.
The survival of white clover is similar to the survival of perennial ryegrass.
Strawberry clovers will survive better than white clover. Viable sub-clover seed particularly will survive extended drought and up to very hot burns. They generally have a large percentage of the seed buried into the ground after spring.
Lucerne has a good record of surviving drought. Established lucerne survives even a very hot burn despite the tops having been burnt. Young lucerne can be killed by a moderate burn particularly if a lot of weeds are present.
Future pasture strategy
Pastures are under a great deal of pressure after drought or fire. It’s important to plan pastures so that establishment is successful and livestock nutrition needs are met.
After fires and drought it can be a good opportunity to assess how to plan for future pastures to perform at their maximum productive and nutritious level. This can be achieved if the right variety and/or mix of species is included, they are well established, soil nutrient deficiencies are addressed and pasture is appropriately grazed and managed.
Affected by drought or fire? Valley Seeds agronomists and our network of distributors can provide expert advice about getting your pasture on track for this season.
The NSW DPI Drought recovery guide 2005 (Part 1) was used to prepare this article.