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Savanna Explorer > North East Queensland > Grazing > Grazing, pasture and soil research

Grazing, pasture and soil research

The following article is from Savanna Links, Issue 33, 2006. Savanna Links is written and produced by the Tropical Savannas CRC.

Wambiana: the big picture on grazing

Variable rainfall in much of the savannas makes sustainable and profitable grazing a challenge. At a working cattle station near Charters Towers, an eight-year research project has been looking at different stocking strategies to deliver the best outcomes for the land, the cattle and the people. By Fran Bancroft and Kate O'Donnell.

Results | Grazing land management | Proactive managementFunding | References |

heavy stocking strategy 05
Above, heavily stocked grazing strategy


healthy pasture under lighter stocking strategy
Healthier paddock under a lighter stocking strategy


heavily grazed pasture on the right, spelled section open for grazing on the right
Heavily grazed paddock on the left, spelled pasture ready for grazing on the right
Photos: Peter O'Reagain

Much of past research in the grazing industry has focused on animal production such as supplementary feeding, early weaning and other measures to maximise livestock production. The Wambiana project has shifted that focus on to the land and sustainable management-by attempting a big picture of the whole grazing system's response to how we manage grazing lands in a variable climate.

Dr Peter O'Reagain and John Bushell from Queensland's Department of Primary Industries and Fisheries (QDPI&F) have led the Wambiana grazing trial for the past eight years. The project, is co-funded by QDPI&F and Meat and Livestock Australia, but has also received support from a range of other funding bodies. The project aims to develop a set of best practices and guidelines for graziers and over the life of the project has assessed the ability of different grazing strategies to cope with rainfall variability in terms animal production, economics and resource condition.

A 1041 ha section of the Wambiana property was leased for the project and divided into paddocks to test five strategies. These were heavy and light stocking, rotational wet season spelling, variable stocking based on available pasture and finally, a variable stocking strategy based both on available pasture and Southern Oscillation Index (SOI) predictions for the coming wet season (see box opposite). The trial is not only examining production and economic performance, but also the effects on pasture composition, biodiversity, woody vegetation and soil and nutrient run-off.

The test area has a highly variable rainfall-the annual average is 653 mm, but the historical range is 109-1653 mm-and most rain falls in January to March. During the first four years of the trial rainfall was good, but has been below average for the last four years giving a good indication of how variable the rainfall can be. The results are providing new facts and figures about sustainable land management.

Results

The Wambiana results clearly show that sustainability and profitability go hand-in-hand in the northern savannas. Light or relatively conservative stocking has consistently given superior individual animal production, a shorter time to turn-off, reduced costs and improved marketability and economic returns. Risk is reduced, land condition maintained or improved and runoff reduced. Variable stocking also performs well, but there is increased risk and an increased level of management is required. Constant heavy stocking performed well initially with the good rainfall, but land condition declined and stock numbers could not be maintained through the dry years without expensive drought feeding.

"In testing heavy stocking we are not recommending it, but we have to know the consequences of applying this strategy," explained Peter O'Reagain.

In low rainfall years, the poor animal production and expense of drought feeding under heavy stocking means that any economic benefit from running more cattle is lost. Land condition also declines and increased run-off means that when rain does fall it does not stay in the land but carries soil and nutrients in to waterways. In the longer term pasture production declines causing a drop in carrying capacity.

Peter O'Reagain sees the results as showing that, despite scepticism from some graziers as being not economically viable, sustainable grazing is the only way forward.

"It's pretty exciting that the trial is showing that sustainable management is not uneconomic but in fact very profitable," said Peter O'Reagain. "It's showing good economic returns for a variety of reasons: better quality of animals, shorter turn-off times, reduced costs and higher rainfall use efficiency.

"Trial data show that over the last four dry years the heavy stocking strategy has run at a loss while light stocking and variable strategies have run at a consistent profit. So any gains from running those higher numbers in the good years are being rapidly eroded away: of course whether this situation reverses when the good years return we just don't know," he said.

Grazing Land Management

The Wambiana trial results are also important in supporting new and existing extension and development programs. One of these is the Edge Network's Grazing Land Management (GLM) workshops delivered by QDPI&F and Meat and Livestock Australia. The GLM package is tailored to each major region to help land managers to manage sustainably and profitably in their own unique set of conditions.

"There is a whole section on management and stocking strategies in GLM, and the main data comparing different management strategies is from Wambiana," points out Marnie McCullough, Extension Officer at QDPI&F. Marnie and other extension officers are working closely with graziers and researchers to ensure that the information and results flow to all parties. "The Wambiana trial is a wonderful resource that we're very keen to promote and encourage people to look at and understand-it's my job to make sure people are hearing about that." According to Marnie, the management strategy that works best depends on the level of management that an individual landholder wants to invest in and their circumstances. "If someone wants minimal inputs, the set stocking approaches are attractive," she explained.

Variable stocking is based on assessing how much feed there is at the end of the wet and adjusting cattle numbers accordingly. Apart from the guidelines and principles from Wambiana, graziers have a suite of existing tools available to help make such decisions including pasture yield standards, the Rainman package, Breedcow and Dynama herd budgeting.

Proactive management

However, strategies like variable stocking are still reactive and stocking decisions are not made until the end of the wet season when, according to Dr Greg McKeon from Queensland's Department of Natural Resources and Water (QDNRW), the damage may already have been done.

"What damages perennial grasses is heavy grazing through the growing season in relatively dry years. So even if stock numbers are adjusted, it is still possible to cause pasture degradation by over-stocking when good seasons are followed by very poor years" he explained.

"Climate forecasting is one tool that managers could use to be more proactive in managing for variable seasons."

At Wambiana the SOI was successfully used to reduce stock numbers before the dry years arrived. Currently, the SOI only has a three-month lead-time, so the cattle were sold in November. Even though this was less than ideal due to poor prices, Peter O'Reagain said the strategy on the whole worked very well.

"The SOI strategy allowed us to cut stock before we ran into trouble with the dry years, as happened under constant heavy stocking. Economically, the strategy performed much better than simply running at a very heavy or very low stocking rate," said Peter.

The SOI strategy was on a par financially with variable stocking, but because of early de-stocking, had better results in terms of pasture condition.

"Ironically, we had a very good wet season at the start of the trial in December 1997, despite initial SOI predictions of a very poor year. By keeping stocking rates low in 1997-98 you could argue there was a potential loss of income," said Peter. "But in terms of land management I don't think so.

"The way I see it, losses from being caught out by drought are far worse than the money you might forgo by not having extra cattle in a very good year."

While the SOI might currently be the best forecasting tool available for Queensland, new forecast systems are being developed for use here and in other parts of Australia. For example, the CSIRO Oceans to Farms project is using Sea Surface Temperature variations to predict rainfall and is using economic modelling to evaluate the usefulness of predictions.

Greg McKeon helped develop the GRASP modelling system that has been in use for many years. He aims to get the model working for the whole of northern Australia and to train people in its use. Similar projects are under way in Australia in NSW and the Northern Territory, and overseas in Zimbabwe where GRASP is used to run management and climate scenarios tailored to these regions. "Part of these studies could involve simulation of the grazing strategies being tested at Wambiana," said Greg. "El Nino affects the climate in many countries. So the idea of linking management to warnings of what's to come, could work around the world."

Pastures can take a long time to respond to management and climate and Peter O'Reagain stresses the Wambiana trial isn't the final word on these issues. However, the data is certainly some of the best available and shows the costs and benefits of different strategies. The important message is not that one strategy is necessarily best, but rather that there are a set of principles and guidelines that can be tailored to particular regions and properties across most of northern Australia.

"From our experiences, I would say your best management must involve spelling and assessing available forage and adjusting stock numbers at least once a year," said Peter. "You should use climate forecasting as an additional tool in making management decisions." Understanding the carrying capacities applicable to your region and land-types is the key.

"Be very careful with your stocking rate and know what the limits are for your area as you change stock numbers with the changing seasons."

Other agency funding   

Several agencies and organisations contributed funding or resources to the Wambiana project: the Tropical Savannas CRC, the Great Barrier Reef Marine Park Authority, the Natural Heritage Trust, the Drought Regional Initiatives and CSIRO. 

References

1. Kutt, A. & O’Reagain, P. ‘Conservation without cost’, Kraatz, M., Clark, M., Jacklyn, P. (Eds) (unpublished), in The Bush Book: A management manual for small areas of native bushland, Tropical Savannas CRC.

O’Reagain P.J. & Bushell J.J. 2003, ‘Effect of grazing strategy on animal production in a seasonably variable tropical savanna’, in Proc. VIIth International Rangelands Congress, Durban, South Africa, July 2003, pp. 913–915.

O’Reagain P.J., McKeon G.M., Day K.A. & Ash A.J. 2003, ‘Managing for temporal variability in extensive rangelands – a perspective from northern Australia’, in Proc. VIIth International Rangelands Congress, Durban, South Africa, July 2003, pp. 799–809.

O’Reagain P.J. & Bushell J.J 2003. ‘The effects of fire on woodland structure and density in a north Australian tropical savanna’, in Proc. VIIth International Rangelands Congress, Durban, South Africa, July 2003, pp. 393–395.  

Contacts

Dr Peter O'Reagain
Principal Scientist
Department Primary Industries & Fisheries
Tel: 07 4787 2155

Fax: 07 4787 4998

PO Box 976
CHARTERS TOWERS, QLD