Restoring productivity in the rangelands
Quality Graze is a 15 year grazing trial at the Department of Industry, Tourism and Trade’s Old Man Plains Research Station (OMP), south-west of Alice Springs. During a period that included both the wettest year and the driest 3 year period on record, production has remained consistent. This stability has helped reduce stress on the human, cattle and natural resources.
There’s little doubt that the La Niña events were critical in accelerating land condition improvement from predominantly C-condition to B-condition for much of OMP. Getting the grazing pressure right has also allowed native pastures to recover. Buffel grass has become more established, contributing to cover and yield increases, especially in the drainage lines.
So what about spelling? At OMP, the grazing trials showed that recovery in ground cover was the same with or without spelling. While there can be many benefits of spelling, such as having fresh feed available for pre-trucking cattle, it has not been the key to improved land condition in these trials. The evidence at OMP is that getting the long-term carrying capacity right is the most critical factor. In big rain years, as long as you don’t increase your cattle numbers, all of the country is effectively spelled because the cattle can’t keep up with the new growth.
In 2015, a new grazing strategy was added, with the stocking rate increased by 50%. The ground cover in this paddock has since declined and is now the lowest of all the strategies. After only 2 years, this paddock had significantly lower cover than the others. Pasture composition in this paddock tends to be dominated by early successional species, typical of what you might find after drought but also a common feature of land in poor condition.
The land condition improvement at OMP has reduced runoff and since 2012 most of the dams have rarely been full. An increase in ground cover and perennial grasses seems to have slowed surface water movement and increased infiltration of rain into the soil. This has improved the land’s ability to respond to rain. On some highly productive land types, the pasture yield per millimetre of rain has more than doubled. Interestingly, there is evidence that where the higher stocking rate was introduced in 2015 there is more run-off into the dam but poorer pasture response to rain.
A valuable characteristic of Central Australian pastures is their ability to retain nutritional quality for up to 2 years after curing. Improved land condition has resulted in more pasture growth and because it retains its value, there is more forage available well into the inevitable dry years. The improved rainfall use efficiency also means that pastures can respond to isolated storms. Even through the driest 3 year period (2017 to 2020) experienced in Central Australia, the Quality Graze project turned off the same number of high quality steers as in wetter years.