Rangeland capability assessment in western Queensland
Cobon, D.H. Mr; Ph: (07) 4658 4400; Fax: (07) 4658 4433; cobond@dpi.qld.gov.au
Research organisation: Queensland Department of Primary Industries, Sheep and Wool Institute, PO Box 519 Longreach Qld 4730
Objectives:
1. To establish the relationship between pasture condition, production of useful biomass and sheep productivity in Mitchell grass areas of different condition classes;
2. To establish a basis for determining the grazing capacity of Mitchell grass pastures in different condition;
3. To determine the effect of growth pattern of weaner ewes on their subsequent reproductive performance;
4. To provide this information as a basis for future decision support packages.
Methodology: Identify areas of different pasture condition then measure the productivity of weaner ewes grazing those pastures. Make concurrent measurements of pasture parameters. Four paddocks (c.250 ha) of different pasture condition were established at Rosebank from pasture condition assessments in May 1990. Ewes are stocked according to pasture utilisation levels which are determined by total biomass, dry matter intake and a predetermined pasture utilisation. Botanical composition and condition (measured by species frequency) of pastures are recorded and changes over time noted. Toorak. Six paddocks (c.130 or 260 ha each) of varying pasture condition were established at Toorak and wethers grazing five of these paddocks are monitored for productivity (liveweight, condition score, annual wool production and characteristics, levels of ammonia in rumen fluid). Botanical composition and condition (measured by species frequency) of pastures are recorded and changes over time noted.
Progress: Data collected from the trials was used to develop a software package called GrazeOn that adopts a pasture budgeting approach to estimate stocking rates on mitchell grasslands in central and north-west Queensland. Stocking rate of paddocks is assessed after the end of each growing season by inputing pasture biomass and condition and density of non-domestic animals. GrazeOn has been validated on seven properties. Workshops have been conducted in the area. The software is available from the DPI and has now been released with a number of other decision support packages on the DroughtPlan CD (also available from DPI).
Period: starting date 1990-07; completion date 1998-06
Status: Finished
Keywords: Mitchell grass; sheep; sustainable; wool, decision support
Publications:
Cobon, D.H. and Peart, S.L. (1995). Astrebla rangeland condition and its effect on the productivity of Merino sheep. Proceedings of the 5th International Rangelands Congress, Vol 1, Utah, USA. pp. 97-98.
Cobon, D.H. and Pinington, G. (1996). User's Guide. GrazeOn - Pasture budgeting for better grazing management - mitchell grasslands. QDPI. Brisbane.
Cobon, D.H. (1996). GrazeOn - Pasture budgeting for better grazing management in the mitchell grasslands. DPI Note. QDPI. Brisbane. Agdex 133/940.
Cobon, D.H. (1996). Adaptive management for sustainability in mitchell grass rangelands (935472). Final project report to National Landcare Program. QDPI, Longreach.
Cobon, D.H., Pinington, G., and Scott, Q.B. (in press). GrazeOn - A pasture budgeting strategy for native grasslands. Proceedings of the18th International Grasslands Congress, Canada.
Cobon, D.H., Pinington, G.K., Crowther, M., Partridge, I.J. and Clewett, J.F. (in press). DroughtPlan CD - Decision support to help manage drought in grazing systems. Australia and New Zealand Climate Forum, Perth.
Stafford Smith, D.M., Clewett, J.F., Moore, A.D., McKeon, G.M., and Clark, R. (1996). DroughtPlan - Building on grazier participation to manage for climate variability. Occasional Paper CV01/97, LWRRDC, Canberra.
