No Plans To Ditch Furrow Irrigation

11 August, 2006

__An investigation of alternative method of irrigating the Australian cotton crop has concluded that while some options show potential, more mileage can still be gained from optimising traditional irrigation techniques.

A joint-presentation to the Australian Cotton Conference by Emma Carrigan and Sarah Hood compared results from several alternative siphon-less irrigation systems.

The study was initiated because of the industry’s commitment to improving Water Use Efficiency (WUE) for economic, environmental, social and political reasons.

Furrow irrigation is the dominant irrigation system and is used by over 90 per cent of the Australian irrigated cotton industry. However, increased precision during furrow irrigation with siphons typically involves higher flow rates using larger or multiple siphons over shorter times than that observed across the industry.

Consequently, irrigators aiming to improve their WUE require further intensification of an already labour intensive system at a time when there is a dwindling labour force. As a result there has been increased interest in less labour intensive irrigation systems.

Four systems were assessed including overhead (lateral move), bank-less channel, bank-less head ditch and pipes through the bank, over the 2005-06 summer. The trial sites were located throughout the Border Rivers and Lower Balonne Catchments.

“The investigation is in a preliminary phase. None of the alternative systems have been fully optimised. The siphon-less and furrow systems evaluated have shown potential to benefit from optimisation and further investigation into “how far the systems can go” is needed to provide a greater understanding of what is achievable for each.

“The gross margin (based on growers estimates) of all the systems confirmed that a significant cost saving in labour can be achieved through the adoption of a siphon-less system at a higher cost of development.

“While furrow irrigation with siphons remains the dominant irrigation method in the Australian cotton industry, efforts towards improving the performance and profit per megalitre of this system still remains of paramount importance,” the presenters said.

Sarah Hood works with Sustainable Irrigation Systems at St George, while Emma Carrigan is with the Queensland Department of Primary Industries and Fisheries at Goondiwindi.

The Siphon-less Irrigation Project is partnered by Sustainable Irrigation Systems, Department of Primary Industries and Fisheries RWUE2, Department of Natural Resources and Mines RWUE2, Cotton Catchment Communities CRC, CRDC, Queensland Murray Darling Committee, Border Rivers- Gwydir Catchment Management Authority, National Centre Engineering and Agriculture, NSW Department of Primary Industries and Aquatech Consulting.

Further information: Emma Carrigan 07 4671 6719 Sarah Hood 0428 255 506

Image: Sarah Hood (left) and Emma Carrigan at the Cotton Conference