The cotton industry has become a hot topic following a Four Corners report which raised concerns about the possibility of illegal pumping of water set aside for environmental purposes. But what is the cotton industry’s relationship to water, and why is it so important?
Where does cotton grow?
About 90 per cent of Australia’s cotton farms are in the Murray-Darling Basin. Mostly grown in the northern areas, cotton is particularly abundant in the Condamine-Balonne, Border Rivers and Namoi regions. Dalby, Goondiwindi, Moree and Narrabri are considered regionally important growing centres.
According to the Australian Bureau of Agricultural and Resource Economics and Sciences, (the research arm of the Australian Government Department of Agriculture and Water Resources) cotton producers often base their planting decisions on water availability and are less likely to be affected by changes in cotton and water prices than other producers. This is because cotton is usually more profitable than other crops such as sorghum, wheat and oilseeds.
How much water does a cotton farmer use?
Cotton Australia reports that the average irrigation requirement for cotton is 7.8 megalitres per hectare. This is less than rice at 12.6 megalitres, but eclipses fruit and nut trees (5.6 megalitres) and cut flowers and turf (4.9 megalitres).
During drought in 2006-7 and 2009-10, cotton production was deeply affected, and fell to a level last recorded in the early 1980s. Similarly, drier seasonal conditions resulted in an industry decline from 2012-15.
Where does the water come from?
In addition to rainwater, cotton growers in the Murray-Darling Basin rely on irrigation water to provide higher and more reliable yields. Flood/furrow systems are the most common, although travelling irrigator systems are growing in popularity.
The graph below indicates the estimated average volumes of water applied to irrigated cotton crops from 2006-7 to 2014-15.
Water trading is also used, although it is more popular in the south due to the limited connectivity of northern river systems in the Murray-Darling Basin.
Cotton Australia says that water use efficiency is improving in the industry, with a 40 per cent increase in water productivity over the past decade.