The Foundation for Arable Research updated growers on a verification trial for a gamma radiation spectrometer service at Crops 2022 field day in Chertsey. Photos / Tim Cronshaw
The Foundation for Arable Research updated growers on a verification trial for a gamma radiation spectrometer service at Crops 2022 field day in Chertsey. Photos / Tim Cronshaw
The results of a gamma radiation spectrometer service are being put through the wringer to see if it can advance soil sensor technology for arable farmers.
Foundation for Arable Research (Far) is working with the North Island’s Eastern Institute of Technology (EIT) to see if mapping by Canadian-based company SoilOptix lines up with other sources.
At Far’s Crops2022 field day last year, growers were told that validation trials were being carried out at five farms and three Far sites including its Chertsey base.
They’d also been mapped out with the proven technology of an electromagnetic machine and grid sampled to provide a baseline for comparison against the SoilOptix results.
Once the analysis is completed researchers hope to work out the return on investment from gamma radiation mapping compared with grid or zone soil mapping and electromagnetic field measuring.
The service produces 25 layers from a survey to map nutrient and physical soil properties, including pH, soil texture, organic matter, carbon as well as elevation and plant water availability.
It’s expected to provide carbon mapping results as well as acting as a management tool for nutrients and water on farms.
Available technology includes a Veris Sensor to measure electrical conductivity in soils and a sensor to measure their electromagnetic (EM) fields.
FAR technology manager Chris Smith said EM mapping was often used in Canterbury for variable rate irrigation and could result in 20 per cent savings in water.
He said some software packages worked out the return on investment from crop yields, the cost of variable rate irrigation, savings on avoiding watering where it wasn’t needed and the crop’s value.
Some growers used it for placing moisture probes, variable rate seeding, identifying potential nitrogen losses and soil sampling in zones.
“It’s been a proven technology and around for many years. One thing about it is once you’ve done it you don’t have to redo it for a short to long term. We’ve had surveys eight to 10 years ago and gone back and redone them and the zones are exactly the same with the values only slightly different.”
Foundation for Arable Research technology manager Chris Smith goes through the pros and cons of soil-mapping technology, including a gamma radiation spectrometer service. Photo / Tim Cronshaw
Smith said the price of $80/ha, depending on the site, should be a one-off cost and was best analysed alongside yield maps and biomass maps to get the “best bang for your buck.”
He said the gamma-ray sensor sent a signal into the ground and its ability to actively read information coming back made it easier to interpret than other sensors.
“Historically this technology has been around for a while and historically very hard to interpret. The SoilOptix we are looking at and validating is a lot more plug and play.”
There were some good opportunities ahead of it, but the technology needed to be validated, he said.
EIT environmental lecturer Chris Thorman said they were in the early stages of a trial to test if overseas scanning could be replicated in New Zealand.
“Now this is a validation trial, we are not trying to make it usable for you yet, we are just trying to see if it is viable for here in New Zealand, whether the algorithms involved in Canada and are being used across the world in Europe etc are viable here.”
