Wireless Warriors

As the deadly chill of frost starts to settle in the low-lying reaches of Bennys Creek Farm, an alarm shakes Ned Sutherland from his slumber. He jumps on his tractor and goes out in the crushing cold to try to save the macadamia nut trees that the wireless monitoring system shows is threatened by frost.

Sutherland’s 100-acre macadamia nut plantation is located between Bangalow and Lismore on the New South Wales North Coast. In terms of farms in the area, Sutherland’s macadamias are a relatively new industry. He is banking on the wireless data monitoring system from integrator Environment Information Technology (EIT) to give him a jump on his competitors.

EIT’s system uses soil probes to monitor things such as soil moisture, salinity and temperature, and wirelessly transmits that data -- often at half-hourly intervals -- back to a central location where it is graphed and viewed online. Sutherland finds the frost detection capability invaluable.

He pre-sets the alarm to go off at a certain temperature so it gives him time to get to the affected trees and irrigate them to try to ward off the deadly effects of frost. “It’s very accurate and very good and inexpensive to run because it’s solar powered. What the probe detects is radioed back to the office or house,” he says.

He hopes to take it a step further so that when the probes detect temperatures indicative of approaching frost, the monitoring system will kickstart the irrigation system automatically and Sutherland won’t even have to get out of bed. EIT first started to use microprocessors in field data collection in Australia in 1981 and claims to be the first in Australia to do so.

“The Department of Agriculture had a problem trying to correlate disease and temperature and wetness in plants.”

“We produced equipment to aid field studies and water quality,” says EIT’s head of R&D Rob Hannah. Initially there were a lot of wired systems in agriculture to run data back but wires are expensive to install and also machinery ploughing through paddocks tended to rip them up.

“Wiring is not a good option in agriculture, so hence the move to radio,” he says. Generally, wireless monitoring systems out in the paddocks require lower speeds of data transmission but they have to be very robust to withstand being out in the weather with little protection against the elements.

They also have to have low power consumption, ideally solar power. “It has to be reliable because a lot of field studies are established thousands of kilometres away from the person doing the trials,” Hannah says.

EIT does some of its own installations in the Northern Rivers area but primarily sells the wireless monitoring systems to people who run irrigation design and installation companies.

The scarcity of water and the escalating cost of irrigation are making people look at water efficiencies. Historically, field data like this was recorded using pens on charts or magnetic tape, Hannah says.

“Then we had solid state memory on removable, robust sealed modules that saved data. Recently there’s emerged a need for distributed monitoring in agriculture, or up and down rivers for water quality studies such as in the Hunter Valley [NSW].”

Once farmers decide to do soil-moisture monitoring of their crops for water efficiency or optimisation of growth, then using EIT’s wireless solution is not generally a big decision says Hannah. “Once they see the usefulness of the data and that it’s going to save them money or increase their yields, then they can justify the cost of the solution.”

On average, to put in a soil probe and a complete radio transmitter node costs around about $3000 by the time it’s installed, Hannah says. “The radio connection is 30 percent of the install. The remaining 70 percent is the measuring equipment.”

Sutherland says it takes seven years for a macadamia tree to mature so it is ready to bear a crop. “A mature tree can give you 20 kilograms of macadamia nuts a year at up to $4 per kilogram,”  he says. Given they are very sensitive to frost, even if the wireless monitoring system saves just one tree, it is close to paying for itself over the life of the tree, he says.

EIT has customers all over Australia and internationally. “We have some of our equipment in the Mediterranean Sea which transmits data to Greece, so it has to be reliable and have low power consumption. In other places they’re monitoring in heavy rainforest canopies so solar power is not suitable,” Hannah says. In those cases batteries are swapped every six months or so.

EIT’s wireless technology is used on the Sydney Harbour Bridge to monitor temperature and wind-chill factor for the Bridge Climb company. Vineyards use it to deliberately alter the water supply to the vines to ‘stress’ the plants, thus manipulating the flavour of the wine.

“In South Australia where there’s a few smaller vineyards together, they install soil probes on the various vineyards and bring the information back wirelessly to one central point, where they will then feed that into a computer into some sort of internet function,” Hannah says.

The system is also used for gas wells and in waste-water management, and EIT has had enquiries about its product from India and Spain.