1301.0 - Year Book Australia, 2007  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 24/01/2007   
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Contents >> Agriculture >> Agricultural environment

AGRICULTURAL ENVIRONMENT

Australia's average elevation is the lowest of any continent, with a mean elevation just exceeding 200 metres. The dominant topographical feature of the continent is the Great Dividing Range, which spans the length of the eastern seaboard and has a profound influence on regional weather patterns and land use.

Australia's agricultural landscapes support a wide range of soils. Most are ancient, strongly weathered and infertile by world standards, with deficiencies in phosphorus and nitrogen. Those on floodplains are younger and more fertile. Very few are considered good quality soils for agriculture. To offset nutrient deficiencies, superphosphate and nitrogenous fertilisers are widely used, particularly on pasture and cereal crops. Fragile soil structure and a susceptibility to waterlogging are other common features of Australian soils, while large areas are naturally affected by salt or acidity. These soil characteristics restrict particular agricultural activities, sometimes ruling out agricultural activity altogether.

With the exception of Antarctica, Australia is the world's driest continent. More than a third of the continent is effectively desert; over two-thirds of the continent is classified as arid or semi-arid. The wet summer conditions of northern Australia are suited to beef cattle grazing in inland areas and the growing of sugar and tropical fruits in coastal areas. The drier summer conditions of southern Australia favour wheat and other dryland cereal farming, sheep grazing and dairy cattle (in the higher rainfall areas), as well as beef cattle. Within regions there is also a high degree of rainfall variability from year-to-year, which is most pronounced in the arid and semi-arid regions. Rainfall variability is very high by global standards and often results in lengthy periods without rain. The seasonality and variability of rainfall in Australia requires that water be stored, and 70% of water consumption is accounted for by the agricultural sector. Under normal seasonal conditions, the ability of primary producers to store water ensures that there are adequate supplies of water for those agricultural activities requiring a continuous supply. The development of large-scale irrigation schemes has opened up areas of inland Australia to agricultural activities which otherwise would not have been possible.

Evaporation is another important element of Australia's environment affecting agricultural production. Hot summers are accompanied by an abundance of sunlight. This combination of climatic variables leads to high rates of evaporation. Areas that have been cleared for crop and pasture production tend to coincide with areas that receive five to nine months of effective rainfall (where rainfall exceeds evaporation) each year. In areas of effective rainfall of more than nine months, generally only higher value crops or tropical crops and fruits are grown, while in areas with effective rainfall of less than five months, cropping is usually restricted to areas that are irrigated.

Since European settlement the vegetation of Australia has altered significantly. In particular, large areas of Australia's forest and woodland vegetation systems have been cleared, predominantly for agricultural activity. The areas that have been altered most are those which have been opened up to cultivation or intensive grazing. Other areas, particularly those semi-arid regions previously cleared of timber and scrub to allow extensive grazing of native grasses, now show signs of returning to their previous condition. In recent years various state and territory legislation has seen restrictions applied to the area of old growth and regrowth forest and woodland that can be cleared without a permit.

For more details see the Geography and climate chapter.

LAND USED

In spite of Australia's harsh environment, agriculture is the most extensive form of land use. At 30 June 2005, the estimated total area of establishments with agricultural activity was 445.1 million hectares (mill. ha), representing about 58% of the total land area (tables 14.1 and 14.2). The remainder of the land area consists of unoccupied land (mainly desert in western and central Australia), Aboriginal land reserves (mainly located in the Northern Territory and Western Australia), forests, mining leases, national parks and urban areas.

Livestock grazing accounts for the largest area of land use in agriculture, with approximately 382 mill. ha, or in excess of 85% of all agricultural land, being used for this activity. In the higher rainfall and irrigated areas, livestock grazing has led to the replacement of large areas of native vegetation with more productive introduced pastures and grasses, many of which have now become naturalised.

For the year ended June 2005 approximately 6% of total agricultural land had been cropped.


14.1 AGRICULTURAL LAND USE - Year ended 30 June

Area cropped
during year
Area of
grazing land
Area of
establishments with
agricultural activity
Proportion of
Australian
land area
mill. ha
mill. ha
mill. ha
%

2001
24.5
n.a.
455.7
59.2
2002
24.1
n.a.
447.0
58.1
2003
23.6
341.3
439.5
57.1
2004
26.1
367.6
440.1
57.2
2005
26.7
382.3
445.1
57.9

Source: Agricultural Commodities, Australia (7121.0); ABS data available on request, Agricultural Survey.

14.2 AREA OF ESTABLISHMENTS WITH AGRICULTURAL ACTIVITY - 30 June

NSW
Vic.
Qld
SA
WA
Tas.
NT
Aust.(a)
mill. ha
mill. ha
mill. ha
mill. ha
mill. ha
mill. ha
mill. ha
mill. ha

2001
61.0
13.2
146.0
57.3
109.2
1.9
67.1
455.7
2002
63.4
12.8
141.4
53.5
109.0
1.8
65.2
447.0
2003
65.1
13.4
139.0
54.1
102.7
1.8
63.3
439.5
2004
63.6
13.6
144.3
52.5
101.2
1.7
63.1
440.1
2005
64.4
13.9
143.8
54.1
104.6
1.8
62.5
445.1

(a) Includes ACT.
Source: Agricultural Commodities, Australia (7121.0).


IRRIGATION

The high variability in river flow and annual rainfall, which are features of the Australian environment, means that successful ongoing production of many crops and pastures is dependent on irrigation. In 2004-05, just over a quarter (35,200) of all agricultural establishments reported irrigation activity. In total 10,100 gigalitres of irrigation water was applied in 2004-05, an average application rate of 4.2 megalitres per irrigated hectare.

Rice is only grown in areas that can guarantee an adequate supply of irrigation water. Grapes, cotton, vegetables, fruit (including nuts) and sugar cane are the other most intensively irrigated crops, with 90%, 89%, 89%, 74% and 40% respectively of their total growing areas being irrigated in 2004-05. However, the total area of land irrigated, about 2.4 mill. ha in 2004-05, represents less than 1% of the total land used for agriculture (table 14.3).

Most irrigated land is located within the confines of the Murray-Darling Basin, which covers parts of New South Wales, Victoria, Queensland and South Australia.


14.3 AREA OF CROPS AND PASTURES IRRIGATED - 2004-05

NSW(a)
Vic.
Qld
SA
WA
Tas.
NT
Aust.
’000 ha
’000 ha
’000 ha
’000 ha
’000 ha
’000 ha
’000 ha
’000 ha

Pastures (native or sown)
For grazing
277
425
^46
^46
n.p.
39
n.p.
842
For seed production
*3
n.p.
*1
^17
n.p.
3
n.p.
33
For hay and silage
48
^63
^22
^13
n.p.
^3
n.p.
151
Cereal crops
Cut for hay
^17
*7
*7
*2
**-
^-
-
^33
For grain or seed(b)
237
^25
^38
*3
**3
4
-
309
Not for grain or seed
^8
*1
*8
*1
**-
2
-
^19
Rice
n.p.
n.p.
-
-
-
-
-
51
Sugar cane
n.p.
-
209
-
n.p.
-
-
213
Cotton
146
-
^124
-
-
-
-
270
Other broadacre crops
^30
^9
^11
*3
n.p.
8
n.p.
63
Fruit trees, nut trees, plantations or berry fruits
26
^30
31
19
^9
^4
2
122
Vegetables for human consumption
^16
23
31
16
7
16
-
109
Grapevines
36
36
*4
61
^8
*1
-
147
Total(c)
910
636
542
184
45
86
4
2,405

(a) Includes ACT.
(b) Excludes rice.
(c) Totals include other pastures or crops n.e.c.
Source: Water Use on Australian Farms, 2004-05 (4618.0).


More information on the use of water by the agriculture sector is provided in the Environment chapter.



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