A new calibration module for Yara‘s N Sensor machine will allow the machine to make the decision about what level of fertiliser to apply, according to the firm’s Stefan Reusch.

“At the moment N Sensor is relative – you calibrate it to a spot in the field, or tell it what rate you would like to put on the whole field, which it then variably applies.”

The new absolute calibration would make the decision on how much to apply based on a scan that would calculate how much N was in the crop, and from there decide how much N would be needed to fulfil the crop’s requirements until the next planned application, he said.

Yara is developing software that will allow its N Sensor to determine N rates in the field,
the firm’s Stefan Reusch (left) and Mark Tucker said

It would require the grower to enter details including crop, growth stage, yield target, timing of next application and a rough estimate of the amount of N mineralisation since the last sensor reading, he said.

Two users had been trialling a prototype model this spring, Yara’s Mark Tucker said. “We hope to extend it to more users next season.”

Fifteen orders for N Sensor machines at Cereals 2008 highlighted the interest growers had in making their fertiliser use more efficient, he noted.