Summary
Most of the pasture grazed by cattle in northern Queensland is found in the understorey of various types of Eucalypt woodlands (forest country). This understorey is made up mainly of native pastures. A highly variable climate means that forage supply varies greatly from year to year and this coupled with relatively infertile soils creates an environment where perennial grasses, the key component of production and landscape health, are susceptible to over utilisation. The only practical management options available to producers to manage perennial grasses are grazing, spelling and fire. With this in mind Meat and Livestock Australia initiated the ECOGRAZE project in 1992 to improve our understanding of the effects of grazing, spelling, fire and climate on the condition and productivity of open eucalypt woodlands in north-eastern Queensland with the following objectives:
1. Develop management guidelines on the use of stocking rate, fire and strategic spelling to encourage deteriorated native pasture back to a more desirable state and to prevent decline of pastures presently in good condition.
2. Transfer management recommendations from Objective 1 into a range of extension activities, including property management planning modules, small group activities, landcare groups, training workshops.
3. Assess the economic benefits and costs of various grazing management strategies.
The focus of the ECOGRAZE project was to understand how pastures in different condition respond to grazing, spelling and fire and from this understanding develop grazing management options. Grazing plots were established on each of three land types in the region with land in either good condition (dominated by native tussock perennial grasses) or a deteriorated condition (perennial grasses still present but annual grasses and forbs and undesirable perennial grasses common).
At each site and in each land condition three different utilisation rates were imposed; 25%, 50% and 75%. Utilisation means the percentage of forage grown in a year that is consumed eg. for 25% utilisation, one-quarter of the forage grown in that year is consumed. The utilisation treatments aimed to achieve a wide range of grazing pressures from conservative to very high. In addition to these continuous grazing treatments wet season spelling treatments were included. Wet season spelling was imposed following the first significant rainfall event (>50 mm over two days) from November onwards. Paddocks were spelled for eight weeks and then the grazing treatments were reimposed. Each year measurements were made of pasture composition, forage availability, grazing preferences, and soil condition. Grazing commenced in 1992 and the study concluded in 2001.
The ECOGRAZE study has proven to be a successful long-term study which has developed innovative management options to enhance the condition of grazing lands in the open eucalypt woodlands of northern Australia. An important aspect of the research has been its location on five commercial grazing properties on different country types in north-east Queensland. This has allowed extrapolation of the results to a wide area across northern Australia. Another important part of the research was to be able to communicate concepts of land condition and this was successfully achieved by using a simple framework to explain land condition states and the factors (grazing, climate, fire) that drives the transitions between states.
The key findings of the field research and the economic modelling have been:
• Grazing management, not climate, is the key driver of land condition and pasture health
• Land was maintained in good condition by continuous stocking at 25% utilization or early wet season spelling followed by 50% utilization
• As perennial grasses are lost through overgrazing, rainfall effectiveness declines, pasture productivity is reduced and the system becomes desertified
• Continuous stocking at 25% utilization or early wet season spelling followed by 50% utilization recovers native tussock perennial grasses in poor condition pastures, even during drought years
• The value of wet season spelling is enormous and where a wet season spelling regime can be implemented it can provide increased flexibility to enterprise management
• Wet season spelling can be implemented using fairly simple two, three or four paddock grazing systems
• Cash flows between good and deteriorated pasture condition were on average not greatly different but pastures in a deteriorated condition gave more variable returns and there were more years in which losses occurred. If deteriorated pastures become degraded, the loss of productivity and increased supplementation costs can lead to huge financial losses
• Where wet season spelling is introduced and overall utilisation rates can be sustainably increased then cash flows can be improved even allowing for the capital costs of infrastructure developments such as water and fencing
These recommendations are increasingly being adopted by the grazing industry in the north, especially recommendations relating to the use of wet season spelling. This management option in particular has been well accepted by industry because it leads to rapid recovery of pastures and provides more flexibility than continuous conservative stocking. The ECOGRAZE findings have been promoted through producer field days, Meat Profit Days organized by Meat and Livestock Australia, brochures and their inclusion in QDPI Future Profit courses. More recently, the ECOGRAZE results have been incorporated into a major Grazing Land Education package developed specifically for producers in northern Australia.
ECOGRAZE has raised awareness of the interaction between grazing and land condition in the savannas of northern Australia. It has been particularly successful at demonstrating that grazing management rather than climate is the major determinant of pasture condition and health. This change in attitude amongst producers has led to an acceptance that more attention needs to be made to grazing management and this is now being observed in changed management practices. Another area where ECOGRAZE has influenced perceptions is through the linking of grazing management, land condition and enterprise Cost analysis. The field study results appear to have much more credibility when they are put in the context of enterprise Cost analysis using realistic case study properties. Because the ECOGRAZE study ran for eight years during which both severe drought and good seasons were experienced, producers have confidence that the results are relevant to their situation.
Near the start of the project an evaluation of four producer groups using a focus group approach was undertaken to document current grazing management practices and sources of information on grazing management. These focus groups will be reassessed over the next six months to determine in amore formal evaluation what impact the grazing research has had on producer awareness, attitudinal changes and adoption of grazing management principles flowing from the research.
The research work undertaken in this project was at the scale of small paddocks. Future work needs to examine how the grazing management recommendations from the research influence land condition and production outcomes at the scale of commercial paddocks and properties. The grazing management recommendations need to be assessed at this scale in combination with other advances in fire management, weed control, supplementation, genetics ie. a whole enterprise approach to grazing management.
