Mitigating Drought at a Farm Scale

At a property level, policies for stock, pasture, and crop management tend to be based on expectations of average climate rather than on an extreme event such as drought. There is also a degree of flexibility to cope with the eventuality of extremely dry periods, although there comes a point when the most economic approach is to deal with drought when it happens (e.g., Daly, 1994). Strategic and tactical responses to drought differ according to the type of enterprise, and a variety of information is synthesized on fact sheets on various state government Web sites (e.g., http://www.longpaddock.qld.gov.au/QueenslandDroughtMonitor; http:// www.dpi.qld.gov.au/drought;http://www.agric.nsw.gov.au). Strategies in nonirrigated cropping lands may include diversification of crops with varying degrees of drought resistance, sequencing of crops and fallow, or adjusting fertilizer application.

If drought results in the failure of a crop, the only alternative is to either do nothing or to plant a short-season crop. In pastoral lands, the options are also limited (Bureau of Agricultural Economics, 1969). One of the most important strategies is to maintain a conservative stocking rate in most years to reduce forced destocking, conserve fodder, make animals physically better prepared for dry conditions, and make feed available for purchase of stock from nearby areas.

A number of computer-based decision-support tools (e.g., Drought Plan; http://www.regional.org.au/au/asit/compendium/i-06.htm) have been developed to help primary producers assess options for drought management (White and Howden, 1991). Many decision-support tools are based on farm-scale agronomic models and allow alternative management strategies to be simulated and tested over a long (approximately 100-year) period. Results can be expressed as probability distributions to indicate the risk associated with specific management options and the degree to which ENSO, for instance, changes this risk. Agronomic models such as GRASP and AP-SIM (described later in this chapter) have demonstrated the usefulness of ENSO-based statistical climate forecasts for a range of decisions, including those linked with drought management in both cropping and grazing lands (Hammer et al., 2000).

The remainder of this chapter focuses on the broad-scale monitoring of drought and, in particular, the development and implementation of a national drought alert system. The system has proven valuable in assisting the process of objectively allocating drought relief and has the potential to improve preparation and planning for drought by focusing attention on emerging drought situations.

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