Efficient Irrigation Improves Pasture Productivity
Increased competition for water means the whole community is looking at how irrigators use water.
He had also noticed nearby tomato farms were no longer irrigating by flooding water down furrows, but were using buried drip irrigation systems.
One had rotated tomato crops out of a drip irrigation paddock and sowed lucerne. “We were impressed with the results he achieved using drip irrigation to grow lucerne,” Dixon says.
Hence Dixon decided to install 20ha of sub-surface drip irrigation on his farm in northern Victoria, in late 2007. He added another 20ha of drip irrigation in 2012 and now permanently grows fodder on this 40ha.
He grew lucerne for the first six years on the original 20ha, and maize silage after that. The second 20ha block was sown with maize for the first year and is now growing lucerne.
As well as greater yield and water use efficiency, there are other benefits.
“The whole system is automatically controlled,” says Dixon. “I set a program on the irrigation controller and the pump starts, and it changes blocks over after the allocated time.
“The controller also automatically injects fertiliser into the water during the irrigation, so these nutrients go directly to the root zone.”
The drip irrigation pipes, or ‘drip lines’, used on the Dixon farm are the same as those used in many other crops.
Polyethylene pipe, 22mm in diameter on the Dixon farm, are inserted underground at a depth of 25cm. Inside the pipe, every 50cm, there is an emitter which regulates the outward flow of water, in this case to 1L/hr.
The system is designed to deliver the peak water requirement – the amount of water the crop will consume per day at peak growing and evaporation periods. The Dixon system can apply 12mm of irrigation water per day.
Dixon decided to install a Netafim sub-surface drip irrigation system. Netafim pioneered the development of drip irrigation in Israel in the 1960s.
For Dixon, there are three main positives. “The sub-surface drip system has allowed me to achieve higher yields and reduce my water use.
“It also requires less labour to operate. On a busy dairy farm needing lots of feed, and with the cost of water increasing, these factors have made the decision to install drip irrigation pay off.”
