Cotton Farming and Water Use Efficiency

Despite its semi-arid climate, sodic soil, and inconsistent rainfalls, Australia features a thriving cotton industry. However, the scarcity of water in the region underscores the necessity of efficient water management. Conservationists hold many perspectives on the best route for developing efficient water use practices in Australia. While public irrigation projects can divert runoff water to cotton-producing territories, Australian cotton farmers must improve their data collection techniques and adopt irrigation techniques that remedy the demands placed by sodic soil in order to increase their water usage efficiency.

Cotton farming in Australia has a long and distinguished history. According to Bridges (1967, p. 73), cotton farming was introduced to Australia during the Civil War, when disruptions to cotton supplies from the American South created global cotton shortages and price increases. To capitalize on the increased demands for cotton, manufacturers sought out Australia as an alternative site for cotton production (1967, p. 73). Further, Bridges (1967, p. 73) noted that the Australian government provided subsidies to support the growth of the Australian cotton industry. Prior to 1959, cotton production was centered in the Queensland valley, where climatic conditions favored growth (1967, p. 73). However, through testing irrigation projects near the Murrumbidgee River, cotton producers determined that they could enhance their yields under irrigation (1967, p. 73). As Bridges (1967, p. 73) noted, cotton production was then located to New South Wales near the Namoi River and Riverina plain during the 1960s. Thus, the practice of relying on irrigation to cultivate cotton began by the latter 20th century.

Inconsistent rainfall and severe weather conditions can have a devastating impact on the Australian cotton industry. As Foster (2011, p. 55) assessed, Australia forecasts for cotton in Australia are expected to be strong, yet fluctuations in yield can significantly impact the profit that farmers receive. As Foster (2011, p. 55) explained, Australian cotton is forward sold, meaning that farmers could lose on anticipated profits when unexpected shortfalls occur in production. For example, the industry was threatened in 2010 when floods in Queensland created a 7 percent reduction of total cotton in Australia and lowered the yield for additional seasons (2011, p. 55). The at-capacity irrigation dams in Australia present another challenge. As Foster (2011, p. 55) noted, public irrigation dams in cotton-producing regions were at 90 percent of their capacity. Consequently, while the industry is expected to grow, the capacity to accommodate increased water needs is hitting its peak. Australia would benefit from the construction of a Grand Ethiopian Renaissance-like dam.

Today, the congregation of cotton producers in areas that are not naturally hospitable to cotton production holds many challenges for land and catchment management. First, data collection practices among farmers make it difficult to collect accurate water use statistics. As Tennakoon and Milroy (2003, p. 184) found, few Australian cotton farmers use sound data collection practices to record their water and soil inputs. Thus, Tennakoon and Milroy (2003, p. 184) asserted that better data collection practices among farmers play a critical role in improving water management efforts. Further, land managers face the challenge of meeting the needs of cotton farmers and preserving the environment. As Kingsford (2009, p. 4) noted, government sponsored irrigation projects, such as the construction of the Murray-Darling Basin, created significant disruptions to the ecosystem. For example, Kingford (2009, p. 4) assessed that the area fish populations decreased by 10 percent and the waterbird population declined by 80 percent within a twenty-five year period. Further, irrigation projects disrupt the flow of water in other areas, challenging biodiversity in regions that extend beyond the irrigation area (2009, p. 4). The environmental demands of cotton farming increase the need for cooperation among catchment managers and land managers in order to carefully monitor the impacts of irrigation.

Redirecting runoff water from the north to the agricultural regions in the southeast is one proposed solution to meeting the irrigation needs of cotton farmers. As Petheram et al. (2010, p. 1792) discussed, fully utilizing water resources is important in Australia because irrigated agriculture accounts for 70 percent of water usage on the continent. Yet, Petheram et al. (2010, p. 1792) noted that while the Murray-Darling Basin in the southeast accounts for 65 percent of Australia’s irrigation, it has been severely impacted by drought in the past decade. The researchers further assess the feasibility of transferring runoff water from the north to the southeast. As Pethreram et al. (2010, p. 1814) noted, 64 percent of surface runoff is generated from northern Australia, yet only 45 percent of that water is yielded in irrigation. However, the inefficiencies of redirecting runoff from the north may outweigh the benefits. As Petheram et al. (2010, p. 1814) noted, transporting water from the north to the south would be costly and potentially only increase Australia’s water resources by 2 percent. Further, cultural barriers may interfere with irrigation projects. Aboriginals have a religious connection to water sources and may express opposition to effort to modify bodies of water (2010, p. 1795). As the researchers reveal, there are many challenges imposed by attempting to redirect rainfalls from precipitous regions of the country to semi-arid zones.

Another proposed solution involves utilizing efficient irrigation methods on sodic soils. As Bhattarai et al. (2006, p. 48) note, 30 percent of cotton produced in Australia is grown on Vertisols, which are soils consisting of heavy clay. A side product of irrigating sodic soil is that it can lead to over-irrigation, excessive runoff, and drainage (2006, p. 48). However, research shows that altering the irrigation method employed can yield efficiencies on clay soils. In a comparison between subsurface drip irrigation (SDI) and furrow irrigation, research demonstrated that SDI could capture up to 250 millimeters in additional rain that furrow irrigation (2006, p. 36). However, the research also revealed that there were some tradeoffs to be made in adopting SDI. First, the maturity of cotton crops that were irrigated using SDI was delayed by twenty-five days (2006, p. 36). This may hinder the savings in water use that farmers would gain from switching to this method. Further, it was determined that SDI produced lower yields in comparison to furrow irrigation (2006, p. 36). However, from a conservationist standpoint, Bhattarai et al. (2006, p. 36) asserted that SDI was a beneficial practice for improving irrigation outcomes and preventing environmental degradations from planting crops on clay soils. This research demonstrates the importance of adopting techniques that consider the sodic nature of the soil in order to improve efficiencies in water use.

With public irrigation dams reaching their capacity, it is crucial for Australians to adopt water conservation methods that will make efficient use of their limited water resources. Because Australian farmers have developed their industry in areas that are least hospitable to growth without the aid of irrigation, they depend on effective solutions that will enable them to survive drought conditions and extreme weather conditions. Yet, the research demonstrates that many proposed solutions carry significant tradeoffs. While the northern region of Australia provides significant runoff from rainfall, redirecting this would cause logistic and social problems. Further, the costs and investment of constructing water pipes may not be worth the modest increase to water resources. Additionally, drip irrigation systems can be used to counter the detrimental impacts that clay soil has on water efficiency. In order to improve efficiency, Australian farmers must improve their data collection methods so that they can work with researchers to develop efficient irrigation practices suited to the soil.

References

Bhattarai, S.P., Mchugh, A.D., Lotz, G. & Midmore, D.J. 2006, "The Response of Cotton to Subsurface Drip and Furrow Irrigation in a Vertisol", Experimental Agriculture, vol. 42, no. 1, pp. 29-49.

Bridges, E.M. 1967, "Cotton in Australia", Geography: Journal of the Geographical Association, vol. 52, no. 1, pp. 73.

Foster, M 2011, “Crops: Cotton”, Australian Commodities, 18, no.1, pp. 52-59, Business Source Complete, EBSCOhost, viewed 7 October 2013.

Kingsford, R.T. 2009, "Managing Australia's Scarce Water Resources for the Environment", Pacific Conservation Biology, vol. 15, no. 1, pp. 4-6.

Petheram, C., Mcmahon, T.A., Peel, M.C. & Smith, C.J. 2010, "A Continental Scale Assessment of Australia's Potential for Irrigation", Water Resources Management, vol. 24, no. 9, pp. 1791-1817.

Tennakoon, S.B., & Milroy, S.P. 2003, “Crop water use efficiency on irrigation cotton farms in Australia”, Agricultural Water Management, vol. 61, pp. 179-194.