THOUSANDS of dollars in savings from reduced water use could be on the way to irrigators, as research into variable rate irrigation returns encouraging results.
Varying the amount of water applied to pasture from a centre pivot depending on soil type and weather conditions has saved $5,300 in energy and water use a year at a research trial site on a dairy property in northern Tasmania.
The project, lead by the Tasmanian Institute for Agriculture, found potential savings on other sites under consideration may reach $12,000 a year.
Sensor technology was deployed to collect data on power and water use, as well as soil moisture. Combined with topography and soil type, a map is produced of the landscape change under the irrigators’ sweep.
The data is overlaid with weather and evaporation information and the inputs crunched to calculate an optimum watering rate under the centre pivot’s sweep across the paddock.
Project leader, Dr James Hills, said mapping the shifts soil and topography irrigated area is crucial, and enables irrigation rates to be targeted as the season progresses
“By installing a variable rate irrigation on our trial site at Montana we saw a 29 per cent reduction in water use,” said Dr Hills, a University of Tasmania research fellow.
“On a pivot of 55 hectare this could potentially save up to 70 megalitres over the irrigation season that could be used elsewhere on the farm to increase productivity.
“Typically we have found that variability reduces as the season progresses.”
The project has also shown that effective irrigation scheduling can lead to significant increases in productivity.
“Our monitoring on one farm has found that improving scheduling can increase pasture production by more than 20 kilogram of dry matter per hectare a day (DM/ha/d), which equates to 1.8 tonnes of dry matter a hectare over the key irrigation months,” Dr Hills said.
“The farmer has now made adjustments to the irrigation schedule for this season and pasture growth rates are averaging about 60kgDM/ha/d, compared with only 40kgDM/ha/d at the equivalent time last season.”
Tasmania Institute for Agriculture is a joint initiative between the University and Tasmanian Government. The Tasmanian variable rate irrigation research is part of the Smarter Irrigation for Profit project, which is backed by the federal government’s Rural Research and Development for Profit program.
University of Southern Queensland is also contributing to the project, working on an control module which would run software which automates the variable water rates, based on the data inputs from the field.
Dr Hills will present the findings next week on Thursday, 18 May 2017, 8.30am until 2pm at the Riverlands Centre in Longford, Tasmania. This event is free and open to the public. Click here to register.