Nelson and Marlborough grape growers are turning to inexpensive sensors to help cut irrigation costs and to boost yields
and fruit quality.
The change to new portable sensor technology has occurred as a result of demonstrations throughout the country by
Wanganui Agriculture New Zealand horticultural consultant Colin Spence. The demonstrations of the Diviner sensor, a
hand-held probe, were funded by Technology New Zealand through its TechLink scheme. They showed farmers in late 1998 how
new technology could benefit them.
"We aimed to let growers know that this technology existed, show them how it could assist them, develop their confidence
in it and allow them to discover its potential and how it could be applied to their business," Mr Spence says.
Nelson and Marlborough growers have adopted a monitoring service using the portable technology. A typical client with
three sites pays $1650 a year to use the service with a one-off installation cost of $1100. An operator does not need to
be licensed to use it.
Nelson Agriculture NZ agribusiness consultant Greg Dryden says two of the largest growers in the country, as well as
smaller contract growers, are now using the hand-held probe that is inserted down PVC access tubes dotted about a
property.
"It takes a soil reading by sending out an electric charge and the probe picks up the moisture content in the soil," he
says. "A user reads the display indicating how wet the soil is, and can then make an informed judgement about whether to
irrigate and by how much."
The system makes irrigation more precise.
"The days of irrigating by gut feeling, or kicking the dirt with your boot, are over," Mr Dryden says. "Water is a
scarce resource, pumping it is expensive, and in many cases you have to apply to your local council for a water right
before you can irrigate. District councils are beginning to look very closely at how water is being used."
As well, badly judged irrigation can put stress on plants, leach fertiliser into ground water, induce excessive growth
and lead to an outbreak of plant disease. Grape growers are able to significantly influence quality through controlled
water stress of the vines.
Mr Spence says the shift to more precise methods of irrigation are common in some countries. In the Australian state of
Victoria, for example, farmers use small on-farm weather stations wireless-linked to a PC back at the house. The farmers
can use the system to make disease predictions and control irrigation pumps by shutting them on or off.
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