Demand for high-quality Irish distilling barley continues to grow according to Teagasc’s Dr. Richie Hackett, who addressed the recent Teagasc malting barley webinar.
According to Hackett, the percentage protein within a grain of barley is essentially the ratio of total starch to total protein.
“From a distilling perspective, the objective is to maximise the starch levels within the grain,” he said.
“Starch is produced as a result of photosynthesis. And to maximise this process we need a crop with a good canopy.
“Making this happen requires good germination, good establishment, good tillering, good green-leaf production and the absence of plant disease.”
Protein within barley comes from three different sources: the soil, added manures, and added chemical fertiliser.
“When it comes to growing malting barley crops, we are striving to maximise rates of photosynthesis, without the use of added nitrogen,” Hackett explained.
The key factors that will drive the efficient production of malting barley crops are: good soil fertility; soil pH being at the correct value; phosphate and potash added at the specific levels required by the crop; plus good weed, pest and disease control.
“Trace elements also play a critical role in optimising crop yields,” said Hackett.
“Early sowing also gives higher yields and lower protein values. This is particularly so when crops are grown for distilling purposes.
“However, soil conditions must be appropriate at time of sowing.”
Significantly, Hackett confirmed that a specific nitrogen application can deliver a range of possible grain protein percentages.
“This is the key issue,” he stressed.
“There is no one right rate of fertiliser. Numerous Teagasc trials have confirmed that grain protein levels will rise once fertiliser nitrogen rates rise above 50kg/ha.”
Hackett continued:
“Conversely, grain protein levels will fall as applied nitrogen rates are reduced. But again, at a single nitrogen application rate, grain proteins can be within a very wide range, depending on site weather conditions and a range of other factors.
“So there is an inherent risk in selecting a fertiliser nitrogen application rate that will both maximise yield and the proportion of a barley crop that is selected for distilling purposes.”
According to Hackett, a balance can usually be struck between 110-120kg nitrogen per hectare.
“But this will vary between fields. Growers should always look at the history of a specific field and how it has performed in terms of producing good crops of distilling barley over a number of years,” he said.
The tillage specialist added:
“Teagasc is not recommending farmers to further reduce the levels of nitrogen they apply to distilling barley crops this year.
“Farmers will know from past history what has worked for them. And they should stick with this approach during the season ahead.”