FARMERS are busily crunching the numbers as the winter crop progresses to see whether the premiums for high protein wheat and malt barley lines make a late season nitrogen application, with the primary intention of boosting protein, not yield, is economic.
Simon Craig, partner with Mallee-based consultancy business Farm 360, said manipulating protein levels through nitrogen applications was a difficult process.
“You really need to have an idea of what the starting protein is like and that can be difficult to assess, and then there are the seasonal considerations.”
“For instance, it could be the right growth stage to put the nitrogen out but if there is cool and wet weather after the application the nitrogen may be used by the plant to swell grain size, which will have an impact on yield, not protein.”
Other variables include the amount of mineralised nitrogen in the soil and temperature.
He said applications after growth stage 40 (the booting period) could be expected to influence protein levels rather than yield.
Lee Menhenett, agronomist with Incitec Pivot, said a nitrogen application in the reproductive stage, around GS39 to 45 could be considered a bet each way in terms of yield and protein increases.
“It will probably have an influence on yield and also is likely to boost the protein, although the exact correlation of what happens comes down to the conditions.”
He said yield and protein levels were linked.
“If you’ve got wheat in that ASW class at harvest it is likely you haven’t maximised your yield.
“Once you get to that 10-10.5pc protein level, you’ve probably gone closer to your yield potential.”
Barley requires less nitrogen than wheat to alter its protein, which he said could also be important, given growers are keen to produce malt quality barley this year due to a strong premium.
Mr Craig said the rough rule of thumb was that it required 10 kilograms of nitrogen a hectare (roughly 20kg of urea) per tonne a hectare of expected yield to raise a wheat crop’s protein by one per cent.
For example, if a crop was expected to yield 4t/ha, Mr Craig said 80kg/ha of urea would have to be applied to get the protein response.
This figure is halved in barley, where 5kg/ha N per tonne a hectare of yield is required for the same protein response.
However, the issue in malt barley is the strict delivery requirements of protein levels between 9pc and 12pc.
Mr Craig said farmers would have to crunch the numbers.
“It is not an insignificant amount, especially given farmers have already stretched their input budget this year due to the potential for good yields,” Mr Craig said.
He said he would only feel comfortable once premiums for H1 grade wheat got to $50/t or more above APW.
Mr Menhenett said that on a historical basis, nitrogen prices were cheap.
He said he believed farmers could get an economic response from later season applications when the conditions were right.
“The window is obviously drawing to a close in the earlier developing regions, but through the high rainfall zones there is still quite a bit of time left.”
He said trafficability was an issue through parts of the Riverina, Victoria’s north-east and the Wimmera region, but added planes were being used to get the nitrogen out.
