Enhancing adoption of improved grazing and fire management practices in northern Australia: Bio-economic analysis and regional assessment of management options

Abstract

In this project we enhanced two existing simulation models, GRASP and ENTERPRISE, and used these alone and in combination to evaluate current and candidate ‘best practice’ management options for extensive grazing lands across 6 regions in Queensland and the Northern Territory. The main management options of interest were stocking rate, pasture spelling and fire management. Regions included the Victoria River District, Burdekin woodlands, Fitzroy woodlands, Mitchell grasslands of western Queensland, Mitchell grasslands of the Barkly region, and the Maranoa-Balonne woodlands. Regional workshops with local technical specialists and producers guided and evaluated model outputs. Modelled scenarios of different degrees of stocking rate variability over time suggested that annual increases and decreases of around 10- 25% per year in total stock numbers per property, in line with changing pasture availability, give improved financial outcomes as well as ensuring good pasture condition. Simulations within specific climate windows can produce results where fixed stocking rates perform better than some degree of variation, but these do not appear to be common. Testing of various wet season spelling regimes suggested that spelling for at least 6 months in a four-year period provided accelerated improvement in pasture condition on the spelled paddocks. If animals from the spelled paddocks were accommodated on other paddocks, however, adverse impacts could occur on these stocked-up paddocks if they experienced successive years of higher than safe utilisation levels. Net benefits of spelling regimes for the whole property can therefore be less than expected. Testing of various fire regimes suggested that use of fire to manage unwanted woody vegetation is economic when woody cover is sufficient to be impacting pasture production but not so dense as to be preventing its regular use (through lack of fine fuel).