Terraced irrigation delivers time and money savings

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Campbell Dalton is switching to a new irrigation system for maize and rice to improve labour efficiency on his family’s mixed farm in south-west New South Wales.

The new system comprises a sequence of terraced bays with a 150-millimetre drop between each bay, which, while watered separately, are linked by a bankless channel (Figure 1).

Campbell – who farms with his mother Helen and father Nayce near Yenda, east of Griffith in the Riverina region – says each bay is irrigated by backing-up water behind a closed check gate in the bankless channel, causing water to spill into the adjacent bay and travel along furrows that run perpendicular to the bankless channel.

After the first bay has been irrigated, a gate is opened to allow water to flow into the second bay. The process is repeated until all bays in the sequence have been watered.

Photo of Campbell Dalton in a paddock

Campbell Dalton checks grain prices in a paddock
that has been recently furrowed in preparation for
planting maize in October.

PHOTO: Nicole Baxter 

For Campbell, the main advantage of a bankless channel irrigation system over a siphon-fed system is eliminating the need to change up to 600 siphons every 12 hours.

What previously took Campbell six hours a day to complete, for up to five months, now takes one of his employees 15 minutes a day when crops are being irrigated. This change has released Campbell to work on other aspects of the business.

With 200 hectares (12 per cent) of irrigated land already terraced, Campbell plans to convert the remaining area when finances allow.

From the first week in October this year, Campbell will plant two medium-maturity hybrid maize varieties: PAC 345IT grit corn and PAC 607IT feed corn.

He budgets on producing yields of 10 tonnes/ha on average, but actually targets inputs to grow a 13t/ha average. In Campbell’s first year of growing maize, the crop achieved 13.5t/ha. Although small problems seemed like big problems because everything was new, he says his neighbours and agronomists provided “fantastic support”.

Graph illustration of a bankless channel irrigation system

Figure 1: Schematic of a bankless channel
irrigation system
SOURCE: Adapted from Michael Grabham,
New South Wales Department of
Primary Industries

He was pleased with the return on investment, given the massive flooding that occurred in March 2012.

The flood inundated the maize crop and came within 50mm of the heads, delaying harvest for five weeks. The grain had to be put through a drier twice before delivery.

“It was a long and painful process at 5t/hour,” he says. “But it was worth the effort. We were scrupulous with hairline cracks and fractures, and as a result there were no problems with quality.”

Campbell encourages those considering growing maize in the south to budget on drying grain once every three years.


Region South, North, West