WATER USE IN AGRICULTURE - A SOUTH AUSTRALIAN PERSPECTIVE


INTRODUCTION

This article provides a South Australian perspective on water use for irrigation purposes by agriculture for 2005-06. An overview of South Australian agricultural establishments is given including water usage, water sources and irrigation of pastures and crops. Further information can be found in Water Use on Australian Farms, 2005-06 (Preliminary) (cat. no. 4618.0).

At the end of the 2005-06 financial year, there were 16,457 South Australian agricultural establishments which were estimated to have used a total of 1,020,606 Megalitres (ML) of water for all agricultural purposes. This translates to 10.6% of Australia's total agricultural establishments using 8.6% of the Australian total water consumption for all agricultural purposes.


WATER USE

In 2005-06, 6,322, or 38.4%, of the agricultural establishments in South Australia used 90.9% of total SA agricultural water usage for the purposes of irrigating crops and/or pastures. While the proportion of total agricultural water usage for irrigation is large, it is similar to the national figure (91.9%). South Australia's proportion of total agricultural water usage for irrigation was the third highest of all states and territories.

Interestingly, while South Australian agricultural establishments use 90.9% of total SA agricultural water usage for irrigation, it is still only a small proportion of the total amount of water used for irrigation in Australia. In 2005-06, South Australian establishments used 8.6% of the total irrigation water used nationally (Graph 1). This amounted to a volume of 927,264 ML at an application rate (the volume of water applied per area, denoted by Megalitres per hectare, ML/ha) of 4.2 ML/ha - matching the national average (Table 1). New South Wales used the greatest portion of irrigation water with 41.2% of Australia's total.

In South Australia, 219,000 ha of agricultural land were irrigated, accounting for 8.5% of irrigated area nationally. New South Wales, Victoria and Queensland accounted for 85.7% of the 2.6 million ha of irrigated area nationally.

	Irrigating establishments	Area irrigated ('000 ha)	Volume applied (ML)	Application Rate (ML/ha)
NSW (a)	11413	986	4 472 617	4.5
Vic	11658	657	2 470 542	3.8
Qld	10220	572	2 435 215	4.3
SA	6322	219	927 264	4.2
WA	3249	62	317 703	5.1
Tas.	1917	80	201 822	2.5
NT	352	6	19 546	3.3
Australia	45130	2583	10 844 708	4.2

WATER SOURCES

Whereas other states' and territories' agricultural water was drawn mainly from surface supplies, South Australia's agricultural water was more evenly sourced between surface and ground water. Around 483,000 ML (47.3%) was sourced from groundwater and around 465,000 ML (45.5%) sourced from surface supplies. In comparison, 76.2% of Australia's agricultural water was sourced from surface supplies and only 21.2% from groundwater (Graph 2).



Water sourced from the reticulated mains supply accounted for 5.0% of water for agricultural purposes from all sources in South Australia in 2005-06. This was four times higher than that for Victoria (1.3%), and eight times higher than that for New South Wales (0.6%). This indicates a higher reliance of South Australia's agricultural establishments on this water source. However, South Australia's agricultural establishments were less reliant on reticulated mains supply in 2005-06 than in 2004-05. In South Australia, the proportion of the total water used for agricultural purposes from all sources that was from the reticulated mains supply decreased from 6.5% to 5.0% between 2004-05 and 2005-06.


PASTURES AND CROPS

In 2005-06, irrigation of pasture for grazing accounted for the largest percentage of irrigation water usage by volume in South Australia (Graph 3). Pasture for grazing used 265,079 ML, or 28.6% of all irrigation water used on agricultural establishments in South Australia, followed by grapevines with 24.4%. Nationally, irrigation of pasture for grazing was also the largest consumer of irrigation water by volume of water applied (26.5%).




In South Australia, fruit trees, nut trees, plantation or berry fruits had the highest water application rate with 7.5 ML/ha. Although grapevines constituted the largest area of irrigated land in South Australia with 37.9% of the states total irrigated agricultural land, they had a relatively low application rate of 2.7 ML/ha in 2005-06.


Of the different crop types farmed, South Australia had a higher application rate than Australia for nine of the twelve crop types, the only exceptions being cereal crops for grain or seed; nurseries, cutflowers or cultivated turf; and grapevines.
REFERENCE:

Water use on Australian Farms, 2005-06 (Preliminary) (cat. no. 4618.0)