Historical and Geographical Context (Word

Historical and Geographical Context
Agricultural land use in Australia is circumscribed in large part by climatic factors,
particularly rainfall, including its timing, amount and reliability. The characteristics of soils
become important limiting factors for plant growth at the finer scales of the local
Agriculture, which has reached its present land use after much trial and error,
experimentation and testing, needs to be considered in the context of historical changes.
Land use changes in Australia appear as intensifications in a major response to the
challenges of international markets and profitability.
The successes of Australian agriculture have really depended on the degree to which a
large overseas market existed for a product, that could be produced using little labour, but
required large areas of land and could be transported cheaply. The historical phases of
agricultural development in Australia began with wool, then beef cattle followed by grains
as enabling technologies became available, and now possibly milk products.
Gains in productivity come in response to added inputs and improved efficiencies as a
result of innovations. Increases in productivity might be expected to use the resource base
more intensively and therefore any degradation of the resource would show up in static or
declining productivity, although this may be masked by increased inputs.
Generally a change in land use is a major decision for an individual producer with wideranging ramifications. While world population growth and demands for food and fibre
provide some of the ultimate causes, other immediate causes include: production factors
such as land condition, innovations, and input costs; marketing factors such as quality,
timeliness, and prices; personal factors such as motivations, knowledge, and skills; and
external factors such as regulations, social changes, infrastructure, and government
One method in this study was to update the considerable work presented on land
utilization by Wadham et al (1964). This posed challenges: to condense the changes
considerably and to tailor the products for managers and policy use. Since Wadham et al.
wrote their last edition in 1964, a major groundswell of concern for the environmental
impacts of activities has emerged, manifest in the ESD process, the Decade of Landcare,
and the consideration of the ecological units of landscapes and catchments in planning and
2.1 Geography and climate
Land use, particularly by agriculture, is circumscribed in large part by climatic factors exceptions include the highly intensive, or protected, uses such as urban, glasshouses, and
housed poultry and piggeries. The land uses have to accommodate to the major climatic
types across the continent of wet and dry tropical, humid sub-tropical, dry subtropical,
temperate marine, and semi-arid mid-latitude.
The dominating climatic factor in Australia is rainfall, including its timing, amount and
reliability. It is commonly stated that Australia is the driest inhabited continent with the
largest variability in rainfall. However, there is a large range in total rainfall across the
continent, and it falls at different times. More detailed information can be obtained from
the Bureau of Meteorology (www.bom.gov.au).
From a plant's viewpoint the reliability of rainfall is important to potential productivity. As
an example, Figure 2-1 shows one estimate of reliability for the period July to September.
Figure 2.1 Map showing areas of different reliability of receiving more than 20
mm of rainfall for each of June, July, August and September, based on rainfall
records in Bureau of Meteorology 1900 to 2000.
This simple example, which ignores the differences in evaporation in different places,
assumes that for reliable production of a cereal crop, or for an annual grass to grow and
reseed, requires a minimum of 20 mm per month for four months (as distinct from the
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