2.4 Drought mitigation

Droughts are an integral part of a highly variable climate, as exists over much of Australia. They therefore cannot be eliminated. However, preparing for drought can greatly reduce its impact of drought. Fortunately, the recognition of the Commonwealth, State and Territory governments of the need for a National Drought Policy, ratified in 1992, has been accompanied by a proliferation of aids to assist farmers to become more self-reliant.

The first step in planning for drought is to budget for both non-drought and drought occurrences in the year ahead. More precise planning can be done using decision support systems that take account of the wide range of seasons that can be anticipated in any one environment, and relate these closely to the demands of a particular management system. In this way the production and financial consequences of a whole range of strategic and tactical can be determined, along with the associated requirements for fodder and financial reserves to survive below-average seasons.

Seasonal forecasts are one tool that can assist the planning process, though their usefulness varies greatly with location and farming system. It is important to include four possible outcomes in the planning process. There are drought years that are forecast, and those that are not forecast due to inaccurate forecasts. Then there are non-drought years that are forecast, and those that are not forecast. The opportunity costs of the latter can be very high, in that stocking rates could be reduced, or crops not sown, when a drought year had been incorrectly forecast to occur. Farm income can then be well down, despite the occurrence of a relatively good season.

For livestock producers, knowing when and what stock to buy and sell, and how much of what supplement to feed, can make a very large difference to the financial impact of a drought. A trading strategy in which stock are sold at relatively low cost when pastures dry off, and bought in when rains occur and stock prices rise, can lead to significant financial losses. Choice of an appropriate long-term stocking rate, assessment of available feed and rainfall probabilities at critical times of the year (usually pre-summer and pre-winter), which stock to sell when paddock feed is limiting, and an appropriate level of supplementary feed and financial reserves, are all important.

Livestock that are fed to maintain too much weight can be very expensive to retain, whereas those that are too light in weight can be very prone to losses associated with cold, wet and windy weather. Wheat is often the cheapest supplement in terms of energy relative to cost, although it should be introduced gradually over time to the diet to avoid losses through acidosis. Roughage should also be fed to ruminants in late pregnancy or early lactation. The GrazFeed software developed by the CSIRO Division of Plant Industry, and distributed through Horizon Software, can assist greatly in determining appropriate rations. New South Wales Agriculture has estimated savings of $7.5 million to graziers in southern NSW farmers through careful rationing in feeding supplements during a severe dry spell in1992 drought as a consequence of using this software (Donnelly 1998).

Irrigation is often touted as a means of drought proofing farms, but this is seldom the case in countries where the prices for farm products are not subsidised, and where water is realistically priced. However, irrigation can enable diversification, and allow a range of profitable crops to be produced.

Dryland farmers are well-advised to include drought-tolerant species in their swards.

Specific research projects currently (or recently) being undertaken in this area include:

• Strategies for maximising the persistence of perennial grasses through drought - Dr Jim Scott, University of New England (LWRRDC, MRC)
• Pasture and forage systems (GRAZPLAN) - Dr John Donnelly, CSIRO Plant Industry (AWRAPO; Australia and Pacific Science Foundation; MLA; Australian Pastoral Research Trust; LWRRDC)
• Grazier-based profitable and sustainable strategies for managing climatic variability (DroughtPlan) - Dr Mark Stafford Smith, CSIRO Wildlife & Ecology (LWRRDC, MRC)
• Decision support for climatic risk management in dryland crop production. Mr J.P. Egan, South Australian Research and Development Institute, PIRSA (LWRRDC, GRDC and RIRDC).

References

1. Donnelly, J.R. (1998). Managing the impact of climate variability on temperate agricultural systems in southern Australia. In Climate prediction for agricultural and resource management, edited by R.K. Munro and L.M. Leslie, Australian Academy of Science Conference, Canberra, 6-8 May 1997, Bureau of Resource Sciences, Canberra, pp. 305-318.

Contacts and institutions

Dr John Donnelly, CSIRO Division of Plant Industry, GPO Box 1600, Canberra City, ACT 2601. Ph: (02) 6246 5106; Fax: (02) 6246 5800; john.donnelly@pi.csiro.au

Dr Mark Stafford Smith, CSIRO National Rangelands Program, PO Box 2111, Alice Springs NT 0871; Ph: (08) 8950 7162; fax (08) 8952 7187; markss@dwe.csiro.au