A $1 million, four-year study funded by the MLA and CSIRO and conducted by Queensland’s Department of Employment, Economic Development and Innovation has found that different grazing systems delivered nearly indistinguishable results. The study found no statistically significant differences between the systems with the choice of system relatively unimportant for land health and productivity.
But despite the constant stream of studies that ‘prove’ grazing systems are ineffectual, the practitioners of grazing management fill the top spots in the annual awards.
- Norm Smith, NSW Farmer of the Year for 2011 pioneered planned grazing management on Glenwood, near Wellington. Norm has encouraged greater diversity of desirable species with rotational grazing enabling short graze periods and long rest periods.
- 2011 Runners up, Liz and John Manchee, Narrabri, have increased rotational and cell grazing techniques and have concentrated on smaller paddock sizes.
- Runner up in 2009 Andrew and Megan Mosely, Cobar NSW take a holistic farm business management approach to ensure the business balances social, environmental and economic outcomes.. They believe that increasing soil carbon is the key to overcoming this challenge and prospering in dry times.
- The 2008 winners, Nigel & Kate Kerin, Yeoval, own and manage a cell grazing operation at Yeoval in the state’s Central West with his wife Kate, holistically managing the operations enterprises including sheep, wool, cattle trading and pasture cropping.
- The 2007 Young Farmer of the Year joint winners were both devotees of grazing management: Stuart Blake manages a mixed livestock and cropping enterprise near Walcha. Sheep and cattle are rotationally grazed, promoting continual groundcover that also helps make the most of available water.
- Joint winners in 2007 Ben and Liarne Mannix manage an 18,000 hectare property Gumbooka north east of Bourke in the western division. They use the principles of Grazing for Profit and Holistic Resource Management in their farm management.
- Queensland’s Jack Banks took out the title of 2011 Wool Producer of the Year as part of the Australian Farmer of the Year Awards. Jack implemented a rotation grazing strategy which has resulted in improvements to ground cover.
Why is it so? The gap between farmer experience and scientific experimental results has been acknowledged by scientists. Professor Ben Norton (formerly of Curtin amd Utah State Universities) told a WA Department of Food and Agriculture workshop in 2002, that the majority of published research studies of rotational grazing find that continuous grazing is better than or comparable to rotational grazing in terms of either animal or plant production. Yet “hundreds of graziers on three continents claim that their livestock production has increased by half or doubled or even tripled following the implementation of rotational grazing…” In the McClymont Lecture in 1998 he said: Science, based on 'hundreds of studies' concluded that planned grazing is not cost effective. (Norton, BE., "The application of grazing management to increase sustainable livestock production," Animal Production In Australia, Vol. 22 1998).
Professor Norton concluded that the root cause of the discrepancy between on-farm reality and the artificial ‘pots and plots’ approach which means that there is a methodology problem. The decision to simulate a grazing management situation by using 15ha to test 5 separate grazing systems was typical. All sheep in the trials were confined in small areas which forced them to graze evenly. In the real world, continuous stocking would lead to ‘patch’ grazing, where animals avoid the less palatable species and over graze the more palatable, leading to bare earth and colonization by weeds. Naturally the researchers concluded that there was no effect on herbiage mass from rotational grazing. Therefore, they concluded 'recipes' (exotic grazing management systems) don't work. This study’s findings were unreliable.[1]
The Queensland study of grazing systems also has a flawed methodology: The study failed to observe the basics of scientific method in several ways:
- There were too many variables operating to allow the systems studied to demonstrate their capacities. The properties selected were not representative of any one of the 3 categories of grazing system, but were required to operate at least 2 of the systems at the same time. Instead of clearly defining each category, the properties were graded on a continuum ranging from intensively grazed (cell) to extensively grazed (continuous).
- Animal production data was made meaningless as “livestock were often grazed across different systems within a year”.
- There were too few properties studied to provide enough data to make the results reliable. Only a total of 9 growers were involved across north and south Queensland.
- There was not enough variety in the management style of the growers. Even the continuous grazing practitioners used rest (spelling) and stocked according to the capacity of the landscape.
- Despite the ambiguity of the study, several definitive statements were made based on the findings:
- “There was little or no impact of grazing system on pasture attributes or soil surface condition.”
- “Diet quality was generally lower in the more intensive systems, especially during the growing season.”
- “There was no consistent difference in grazing days per ha due to grazing system.”
- “The intensity of the grazing system had no consistent effect on soil surface condition, pastures or carrying capacity when compared to less intensive systems on the same property.”
The purpose of the study was stated as ‘to assist beef producers make decisions about the most suitable grazing systems for their properties by providing accurate and impartial information.’ The danger is that growers will act upon the results of this flawed study.
The more intense the system, the more invested in fencing and water. "After they saw the study results, one property said they were looking at pulling up every second fence to minimise the labour needed for stock movements," Mr Hall told The Land.
An important part of the scientific method is the “Does it make sense?” test. If the results of trials defy expectations, it is advised that they be subject to scrutiny. In this case, the results confounded initial expectations, lead researcher Trevor Hall said. "We'd thought there would be massive changes, and that's what we'd be quantifying.”
It is hard to conclude that this $1m MLA/CSIRO study proved anything.
What did the readers think?
I setup our cattle to strip graze perennial pastures and or annual fodder crops year-round. Prior to this method, when using set stock rate practices the carrying capacity was up to 3.33 acres/head. While using strip grazing the carrying capacity was up to 1.11 acres/head. However, strip grazing requires more effort, with those results, I'm happy to put in the effort.
