Sensors to aid with soil mapping

Sensors to aid with soil mapping


Grain
Aa

New technology may have an exciting fit in allowing growers to compile accurate paddock soil maps.

Aa
GRDC southern agronomy soils and farming systems manager Stephen Loss with University of Sydney digital soil scientist Edward Jones, who has been working with a range of sensors including a near-infrared spectrometer to scan soil samples and develop a map identifying soil variations across a paddock. Photo GRDC..

GRDC southern agronomy soils and farming systems manager Stephen Loss with University of Sydney digital soil scientist Edward Jones, who has been working with a range of sensors including a near-infrared spectrometer to scan soil samples and develop a map identifying soil variations across a paddock. Photo GRDC..

Grain growers may one day soon be able to map soil in their paddocks without sending a single sample to the laboratory thanks to the efforts of an innovative young researcher.

At present paddock soil mapping, which marks soil on attributes such as pH, water holding capacity and sodicity is heavily reliant on sending in soil samples over a cross-section of the area, but this may be about to change.

Edward Jones is a postdoctoral research fellow from the University of Sydney, who is working on new technology with Grains Research and Development Corporation (GRDC) investment, examining how sensors can be used to scan soil in a manner that allows growers to divide paddocks into management zones.

He has found it is possible to use a range of different types of sensors to scan multiple soil samples across a paddock and build an accurate digital soil map identifying variation within a paddock.

GRDC northern agronomy, soils and farming systems manager John Rochecouste, said the ability to map soil types in paddocks, without sending samples to the laboratory, would be an invaluable management tool for grain growers, potentially saving both time and money.

He said the investment would only need to be made once.

"Soil properties do not change rapidly, so once growers have developed a digital map it would become an important tool to guide their decision making and importantly it would not need to be updated annually."

Even heavy applications of soil ameliorants such as gypsum and lime take a long time before they change a sol's fundamental properties.

Dr Rochecouste said acidity was one thing that could change over time, with a tendency for pH to drop, but added again this happened over a sustained period of time.

However, the soil maps will not incorporate fertility, which is a much more changeable commodity.

"Everyone wants to be able to predict plant available nitrogen, but the technology is not advanced enough at this stage," Dr Jones said.

Mapping soil by sensors requires a massive bank of data in the form of soil spectral images.

He said he was lucky in that the University of Sydney had over 8000 soil samples from across Australia in its library.

From there he built models using the samples in the spectral library to estimate the properties of new samples that were scanned.

He said the task was also made easier by the rapid development of the technology.

"When I started my PhD in 2014 one sensor was the size of a briefcase and cost around US$60,000 but now a sensor that I am currently testing is the size of a deck of cards and costs only US$3000.

"I am very excited for the day that this technology is widely available to growers and advisers, because getting as much information that you can about your soil is crucial to good crop management," Dr Jones said.

The new sensors and digital soil mapping techniques are being trialled at the University's northern New South Wales L'lara research property at Narrabri.

Aa

From the front page

Sponsored by