Australia State of the Environment Report 2001 (Theme Report)
Prepared by: Ann Hamblin, Bureau of Rural Sciences, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06748 5
Physical changes to natural habitats (continued)
Changes in land use in major catchments and IBRA regions [L Indicator 2.3]
A classification developed by Baxter and Russell (1994) for Australian conditions describes five primary categories of land use (Table 14). This classification shows an increasing intensity of use that approximates the degree of transformation from an initial, 'unmodified' state.
|Unmodified||Slight modification||Some transformation||Substantial transformation||Totally transformed|
Source: after Baxter and Russell (1994).
This system has been used in the assessment of the amount of bare land in each biogeographic region, and regional nutrient regimes. A fuller description is given in Baxter and Russell's (1994) system which provides a hierarchical classification for more detailed use, and is distinguishable from many existing systems used in Australia in that it does not focus on tenure. Instead it concentrates on the degree of transformation from a previously less transformed or natural state. National land use mapping has, however, tended to use a mixed land use and land tenure system or composite systems (Figure 29).
Figure 29: Land use in Australia.
The Atlas of Australian Resources (1979) mapped a progressive increase in intensity of land use radiating out from the very large areas of vacant Crown land in central Australia, through low-intensity grazing lands and conservation estate to more densely grazed regions. This transition still persists today, though there are substantially greater diversification than in 1979. In addition, a much larger proportion of the 'land not commercially used' category is in Aboriginal and conservation tenures.
In 1979, cropping was shown as a separate land use only in sugar cane, cotton, horticulture and rice-growing areas. All other cropping areas involved crops rotated with pastures, and were therefore described as 'mixed farming'. In the past 20 years all cropping has increased in profitability relative to animal grazing, resulting in a steady increase in the area of cropped lands (see Figure 31). The management of conventional ley-crop rotations has changed progressively, with both a diversification of the crops grown and a shortening or elimination of grass-based ley rotations (Hamblin and Kyneur, 1993; Walcott et al. 2001).
At the end of the 1990s a much larger proportion of cropping lands were in near-continuous production. This has been associated with increased production per unit area in rainfed grains; with wheat yield increases of more than 90 kg/ha/year (Figure 30). These increases are not an artefact of seasonal variations, as corrections have been made for the effects of season on yield. Consequently the trends can be attributed to the effects of a combination of plant breeding and agronomic practices.
Figure 30: Trends in shire wheat yields, 1982-1997.
Source: Agriculture WA for the NLWRA (2001)
The total area under irrigation has increased by 26% since the early 1980s (Figures 31 and 32) The largest increases have been in New South Wales and Queensland, and this has put significant pressure on the Murray-Darling Basin river systems. Following a basin-wide audit of water use (Murray-Darling Basin Commission 1995) a decision was made to cap the extractions at 1994 levels. In 1997, 1 472 000 hectares were irrigated in the Murray-Darling Basin, representing 71% of the total irrigated area in Australia, and consumed 95% of the water used in the Basin.
Figure 31: Area of crops and pastures irrigated in states and territories, 1984-1998.
Source: MDBC (2000)
Figure 32: Changes in total area of irrigated crops and pastures, 1984-1998.
Source: MDBC (2000)
Historically, low water prices have encouraged inefficient use. About half the total volume of water used in agriculture is for irrigated pasture, and nearly 80% of irrigated pasture land is in the Murray and Murrumbidgee valleys in New South Wales and Victoria (Cape 1997). Irrigated pastures return only one-tenth the value of irrigated fruit, vegetable and vine crops. (Hall et al. 1994). The Council of Australian Governments' water reform policies were introduced in 1998, and water prices have also risen (see the Inland Waters Theme Report). However, statistics on the extent and location of changes in land use resulting from these changes are not yet available. Even among more valuable crops, significant differences exist in the price and consumption of water between districts and between crops, making it difficult to use water pricing and trading as effective mechanisms for increased water use efficiency (Topp and Danzi 1998).
The total number of farms has declined by 18.5% since 1982 (ABS Ag stats Census IRDB 1982-1997). This reflects a growth in large farms: farms between 2500-10 000 hectares, and 50 000-200 000 hectares increasing in number, while farms of less than 50 hectares have declined sharply.
Recent studies by Ha and Chapman (2000) show that productivity growth has been very much greater on cropping farms than on livestock specialist farms, with an average 3.6% growth rate per year for crop-dominated farms (Figure 34). By comparison, productivity growth was 2.6% for mixed farms, 2.1% for beef-only farms, 1.4% for mixed beef-sheep enterprises, and 0.6% for sheep-only farms.
Figure 33: Maximum, minimum and average land use intensity 1983-1997.
Source: Walcott and Zuo (unpublished data)
Figure 34: Broadacre farm total factor productivity growth, 1978-1998.
Source: Ha and Chapman (2000)
Northern and central Australia have lower performance than the 'wheat sheep' belt (which stretches in an arc inland around south-eastern and south-western Australia). Figure 34 clearly emphasises the financial situation of the grazing industries.
At the local scale there are numerous incremental changes at the interface between one land use and the next, tending to blur the distinction between urban and rural land use. There is a progressive intensification of land use in many rural districts close to nodal communication and service centres. Moreover, the expansion of peri-urban populations up much of the eastern coast and parts of the south-western coast is occurring fast, with population growth rates in these areas of greater than 5% per annum (Hugo 1996). These population trends are dealt with in more detail in the Human Settlements Theme Report.
Ha and Chapman (2000) have provided a comprehensive overview of the capacity of farmers to pay for effective environmental management. Basically they shows that, unless farms are performing at a growth rate better the average 2.6%, they are likely to have insufficient financial resources to look after the needs of the environment. The reality is that the majority of farm businesses are in this situation.
A range of recent statistics and studies show that a disproportionately small proportion of farms in any one sector are responsible for the majority of value and volume of production across all commodities (ABS 1997, SCARM 1998, ABARE 1999). Although the '20-80' rule is often invoked in agriculture, in many industries this is now a 10-90 rule; that is 10% of the farms are responsible for 90% of the production value. The significance of this is underlined by the SCARM report (1998) which found that in recent years over two-thirds of farm businesses have made an operating loss.
Less than 8% of Australia's agricultural lands are cropped continuously or in rotation, so by far the major proportion of the land area, particularly in the rangelands and high-rainfall grazing regions, are effectively without resource maintenance expenditure. Despite the enormous efforts of Landcare groups, and the great willingness of volunteers in rural and remote areas to assist in landscape management, lack of cash and capital will continue to be the major restriction to effective control of feral pests, weeds and diseases, erosion, loss of biodiversity and other major environmental threats.
The recent policy statement of the National Farmers Federation and the Australian Conservation Foundation 2000 (NFF and ACF 2000), in calling for a major capital injection into natural resource restoration in Australia reflects the inescapable conclusion that the financial capacity for natural resource management does not exist in rural Australia.