Wambiana grazing trial field day take home messages

For many, the highlight of the day was the field trip, where graziers were treated to ‘speed dating’ type talks from the Department of Agriculture and Fisheries (DAF) grazing team. Graziers were taken to five paddocks on this 1020 ha site, to see the results of the different stocking strategies on pasture condition and animal production.

DAF’s Bob Shepherd, Peter O’Reagain, John Bushell and Paul Jones all presented in the paddock, before the groups headed back to the property for lunch and an afternoon of presentations.

A number of graziers presented in the afternoon sessions, with a welcome given by Don Heatley, former chairman of the MLA board. Michael Lyons from Wambiana Station spoke about managing for pastures and profit, followed by Jamie Gordon who talked about his experience rebuilding the country at Mount Pleasant. Fran Lyons also spoke about the family’s experience getting more grass to grow with improved grazing management at Basalt River.

“DAF has been working with the grazing industry since inception of the trial, and we have all learnt a great deal”, explained field day organiser and project leader, Dr Peter O’Reagain.

“It was wonderful to see so many graziers come along to see for themselves the long-term effects of the different strategies. There was overwhelming support for continuation of the trial and some great ideas on future directions.”

Dr. O’Reagain said that while some of the results were complex, they clearly showed that more sustainable strategies were by far the most profitable. “The results from the Wambiana grazing trial clearly show that in the in the long term, grazing strategies that match stocking rates to forage supply, and incorporate wet season spelling, are both sustainable and far more profitable than heavy stocking rates; the latter are not only less profitable, they also result in pasture degradation and the inevitable loss of carrying capacity and animal production.”

Paul Jones, DAF Senior Scientist, discussed the impact of drought and grazing on the health of valuable native pasture species, such as desert bluegrass. “Desert bluegrass is a long-lived and valuable native pasture species, however its recruitment rates are low and episodic, therefore it is essential to look after the plant species present as they could very well be grazed out during times of drought,” Mr Jones said. “Furthermore, recovery after drought will occur with moderate stocking, but not under high stocking rates.”

“Wet season spelling certainly improves land condition,” Mr Jones continued, “but takes time, and having the right stocking rate is essential for recovery to occur. Removing the grazing pressure over the growing period allows the pasture plants to set seed, thereby increasing plant vigour and provides opportunities for recruitment; making spelling an essential tool in every land managers tool box.”

Co-presenter at the Wambiana grazing trial field day was Principal Extension Officer, Bob Shepherd. “Under heavy stocking rates, currant bush can cover up to 35% of the land area. While fire dramatically reduces currant bush cover, recovery occurs over a four-year period, therefore the continued use of fire on a four to five year cycle is essential.”

“Using fire strategically will also assist to combat woodland thickening,” continued Mr Shepherd. “Woodland thickening occurs on all land types, but the reduction in long-term carrying capacity is at least twice as severe on low fertility land types, compared to those of higher fertility. This has significant implications for maintaining economic viability of beef businesses and reduces pasture cover levels to below critical thresholds in average or leaner seasons, with a flow-on effect to poor water quality, thereby making controlling woodland thickening imperative.”

More details on the trial are available in a recent research publication.

Take home messages from Wambiana grazing trial field day:

• The main productive, perennial and palatable species, desert bluegrass, is maintained under moderate stocking rates (matched to carrying capacity), but without some wet season spelling, desert bluegrass declines significantly during drought.
• All grazing systems must include some wet season spelling.
• Indian couch can increase dramatically under moderate stocking rates during good seasons (eg. 2008–2012), however, it continues to increase during drought (eg. 2014-2020.)
• Wet season spelling may enable desert bluegrass to better compete with Indian couch
• Stylos, even where not sown, are widespread in the region, and will readily colonise native pastures adding to diet quality and animal performance. Stylos increase across all grazing strategies during drought years, but the largest increase is under moderate stocking rates.
• Tree canopy cover rises and falls with the cycle of good and poor seasons. Box country has consistently higher canopy cover than silver-leaf ironbark country. Long droughts (eg. 2014–2020) cause a much larger reduction in canopy cover on silverleaf ironbark country than box country with a correspondingly much poorer response when the seasons improve.
• Under heavy stocking rates, currant bush can cover up to 35% of the land area. While fire dramatically reduces currant bush cover, recovery occurs over a four year period, therefore the continued use of fire on a four to five year cycle is essential.
• Woodland thickening occurs on all land types, but the reduction in long-term carrying capacity is at least twice as severe on low fertility land types compared to those of higher fertility. This has significant implications for maintaining economic viability of beef businesses and reduces pasture cover levels to below critical thresholds in average or leaner seasons, with a flow-on effect to poor water quality.
• Individual liveweight gain per head was on average much better at moderate (117 kg/head) than under heavy stocking (100 kg/head);  animals grew faster, graded better at the meatworks and returned a better market price.
• In contrast, total liveweight gain per hectare was on average higher under heavy (19 kg/hectare) than moderate (14 kg/hectare) stocking.
• However, higher liveweight gain per hectare under heavy stocking only possible with drought feeding (7/24 years vs 1/24 years in other strategies).
  • Animals also had to be withdrawn in droughts under heavy stocking.
  • Consequently average annual gross margin is far less under heavy stocking ($7/hectare) compared with other strategies ($13-$14/hectare) and was due to:
    • Lower price per kilogram at meatworks
    • Reduced production in dry years and droughts
    • Costs of drought feeding.