IN A YEAR when the weather threw its worst at Oxon winter wheat grower Alan Smith, a pilot precision fertilising advice service based on electro-magnetic induction (EMI) scanning (Arable, Apr 2), mineral nitrogen sampling and variable rate applications clearly paid off.
Mr Smith tested the Masstock Dalgety DDF approach on an 11.6ha (29-acre) field of Hereward at Kingham Hill Farm near Chipping Norton.
“It was a real eye opener,” he says. “The fields either side went flat but this one stood.”
Although the yield, averaging 9.4 t/ha (3.8 t/acre), was much the same as the others, the quality in those fertilised as usual was lost to the weather, he says.
“I must admit that before harvest I wasn”t too sure about the result of what we had done. The field was not as green as the others and went off a lot quicker. But that meant we were able to combine it earlier.”
Its protein was about 15% and Hagberg 340-350. “It went for Class 1 milling wheat, no problem.”
By the time the other fields could be cleared the grain had chitted and any bread-making quality had gone. “The Hagberg was down to 70.”
The weather, rather than precision farming, was most responsible for the difference, he admits. But applying nitrogen variably has clearly been a success.
“You are giving the crop what it needs where it is needed. Quite apart from the fertiliser saving, there must be less being leached, so there is an environmental benefit.”
At an average of 189kg/ha (151 units/acre) over the field Mr Smith used a tonne less than his normal application practice would have applied, saving 12/ha (4.90/acre).
As nitrogen inputs come under greater public scrutiny, and to ensure they return maximum value, more accurate targeting will grow in importance, says Dalgety agronomist Gordon Thornton. “There was quite a surprising variation in how much product was applied, from 275kg/ha down to nothing.”
The EMI data, along with previous cropping, yields and information on other inputs was sent to Kemira GrowHow precision farming adviser Robin Thompson and processed using the company”s LORIS software.
“LORIS matches the N requirements to the soil”s yield potential. In trials over five years we have averaged yield increases of 3.5%,” he says.
That software output controlled how much nitrogen was applied in the mid-May second top dressing through an Amazone spreader linked to Farmworks SiteMate VRA software. “We will definitely be extending this over more of the farm,” says Mr Smith.