ONE of the most talked about subjects in agriculture over the last two years has been variable rate product application.
According to Agrarian Management agronomist Chris Pinkey, who spoke to farmers at last week's Northern Agri Group spring field day, the advance of technology has placed it firmly on farmers' radars.
"Variable rate applications are happening now," Mr Pinkey said. "Some farmers already have an excellent database of information about their farm."
According to local farmer Ben Cripps, employing EM38 (electro-magnetic scanning) and radiometrics has put him on the pathway of gathering as much information as possible to form paddock zones.
"We can then get a better handle of water-holding capacity and soil physicality," he said. "EM38 by itself does not work well on the sand plain but with the addition of radiometrics we can measure variations in paddocks to isolate zones to a depth of three metres on the sand plain.
"Once we've scanned the paddocks we do a huge amount of soil coring which can then be analysed in a laboratory.
"For example, we can correlate the score with EM scanning to generate a pH reading which can be formed into a liming map.
"So with EM38 and radiometrics we can create zones to identify what strategies to take to improve productivity.
"We can better understand what is going on in the soil and the limitations to yield.
"Our machines were variable rate-capable, we just needed the software upgrade."
According to Mr Cripps, one of the biggest benefits so far was applying variable rate potassium.
"We actually used the same amount of K the previous year but it was more targeted," he said.
"We also saved about 2500 litres of Flexi-N over 650ha of trial.
"In the future I am hoping we can vary seed rates as dictated by the zones we create and possibly look at herbicides and fungicides."
Yuna farmer Brady Green said he was using Google Earth maps to identify paddock variability.
"We're in the process of going into variable rate and we're drawing up our own zones based on Google Earth maps," he said.
"We're trying to make it as simple as possible.
"We've collected all the data we need and tested 160 sites down to half a metre.
"We've already diagnosed subsoil acidity and compaction as two of our biggest issues by taking samples and doing our lab tests."
