Soil Condition
Testing, developing and promoting principles, guidelines and decision tools for sustainable grazing of tropical savannas
To quantify the long-term (over 10 years) effects of different strategies for managing utilisation on:; 1. resource condition, including cover and patchiness; 2. pasture production and species diversity; 3. soil and nutrient loss (link to Burdekin catchment study); 4. animal performance and production; 5. economic return
Estimating ground coverin northern Australia rangelands using Landsat TM imagery
Ground cover is a key indicator of rangeland condition, but efficient methods to monitor cover over the various land systems of Australia's northern rangelands are still to be fully developed. The potential for using Landsat TM data for monitoring and mapping trends in groundcover is being assessed in northern Queensland. Preliminary results using ten commonly applied vegetation and cover indices suggest the approach could be a valuable monitoring and modelling tool. However, its ultimate success will depend on whether the prototype method can be applied to state and nation wide monitoring. Further fieldwork will be required to calibrate and validate different geographic regions, and the development of multi- temporal and spatial indices (A).
Characterisation and assessment of rangeland resources
A project to characterise and assess rangeland resources conducted a biophysical and socioeconomic inventory of the Ord River catchment in the East Kimberley WA. The tools and capacity developed during the project provide a basis for implementing monitoring programs to assess future trends in rangeland resources. The socioeconomic profile can be used to assist in regional land use planning and management. An assessment of current biodiversity data serves as a precursor to a regional conservation plan and enables the identification of gaps to target future resource allocation. The project also developed a methodology for mapping land units that produces maps of high quality and resolution more cost effectively than traditional field-based methods. Interactive computer-based software, Vegmachine, was also developed to monitor rangeland condition using remote sensing. The results of the project provide a sound basis for an improved understanding of the East Kimberley?s rangeland resources, and the impact of intensified production (A).
Building Grass Castles: Integrating Ecology and Management of Australia's Tropical Tallgrass Rangelands.
The tropical tallgrass rangelands of Australia are declining in condition in response to increased grazing pressure. However, large areas are still in good condition and many of the deteriorated areas are not yet irreversibly damaged. Increases in grazing pressure have been associated with the loss of perennial grasses, woody weed invasion, and increased run-off and soil loss in some areas. The population dynamics, diet selection patterns, defoliation responses of the perennial grasses and impacts of fire are outlined and ways this understanding can be incorporated into management are presented. The perennial grasses are sensitive to defoliation and can only be lightly utilised. Annual utilisation rates should not exceed 25% in areas of moderate and high fertility and this threshold'safe'level decreases to 15% on infertile soils in the monsoon zone of the north and north-west. Spelling pastures during the wet season, when they are particularly sensitive to defoliation, may enable utilisation during the rest of the year to be increased. Such a grazing regime allows fuel accumulation, increasing the opportunity for use of fire in managing exotic woody weeds and the treetshrub layer. Fire can also be used to improve animal distribution and reduce the formation of patches which are prone to soil degradation. Sown pastures and tree clearing can be used to increase carrying capacity and improve flexibility in the management of native pastures but careful consideration needs to be given to these improvements to prevent problems such as salinisation and unwanted spread of exotic pasture plants. One of the difficulties in developing recommendations relevant to management is that most of the ecological understanding is at the plant and plant community scale but most problems occur at the paddocWlandscape scale where our knowledge base is limited. Future work should focus at this large spatial scale so that ecological principles derived from a range of scales can be better integrated into guidelines more appropriate to extensive management of tropical tallgrass rangelands. Key words: grazing, population dynamics, defoliation, diet selection, fire, grass decline
Groundwater quality in the Ord Irrigation area, its sustainability for irrigation and prediction of salinity and sodicityhazards
'June 2003.' System requirements: Internet connectivity, World Wide Web browser, and Adobe Acrobat reader
Introduction (Groundwater and Water Management in the Ord River Irrigation Area)
This paper deals with irrigation farming and changes in groundwater in the Ord River Irrigation Area WA. The ORIA and its water resources are described. The salt tolerance of crop species is discussed and the need for efficient irrigation and scheduling of irrigation noted.