Achieving the right balance between nitrogen content and yield has always been tricky for malting barley growers. Robert Harris finds out why this year is no exception
MALTING barley growers should concentrate on maintaining target grain nitrogen levels rather than increasing yields.
That means sticking to tradition – even new, higher-yielding varieties should be fed limited amounts of nitrogen fertiliser early.
That is what Banks Agriculture, of Sandy, Beds, will be telling its customers this spring. "There has been a lot of talk about the additional yield of new varieties like Angora, Fanfare, Gleam and Melanie," says managing director Michael Banks. Some advisers suggest the extra output dilutes grain nitrogen, so high yielding varieties can cope with more fertiliser.
But such varieties have larger grains which tend to accumulate nitrogen, Mr Banks maintains. "Barleys with a lot of size tend to be nitrogen cuddlers – Puffin is typical." That means they can easily be pushed above 1.7% N, reducing premiums, or worse, over 2%, when they will only be fit for feed.
Growers should aim to apply a maximum of 100 kg/ha (80 units/acre) of nitrogen to first malting barley crops, perhaps 5-10% more on second crops on light land, says technical manager Bob Mills. Company trials reinforce that message.
"Pushing the amount of applied nitrogen had quite a dramatic effect on grain nitrogen last season, despite the typical extra 5 cwt/acre yield. An extra 25kg/ha raised grain N by 0.2-0.3%. We shall be doing more work this year, but on those results I definitely would not recommend increasing fertiliser rates."
Soil testing to fine-tune applications is of limited use, he maintains. "Malting barley growers tend to be fairly conservative. If the test suggests a different rate, most wont follow it. They may be right – some tests dont seem to be that accurate, as they only provide a snapshot at the time they are carried out."
Early March remains the best time to apply nitrogen, he adds. Split applications are not favoured. "You can go too early – most barleys are prolific tillerers, and you can end up supporting too many tillers which increases the risk of shrivelled grain. And applying fertiliser at the end of March or the beginning of April is a real risk – it can push grain nitrogen sky high." Dry soils limit uptake, so much can still be available to the plant later if rains return.
However, Mr Banks is concerned that the amount of some newer varieties being grown is too high. "There is a lot of Fanfare in the ground, for example – more, I think, than the market will want." For some growers, especially those on heavier, marginal malting barley land, it could pay to apply a lot more nitrogen and push crops for feed.n
New higher yielding malting barleys still need careful nitrogen management if they are to make the grade, says Michael Banks.
BARLEY N MANAGEMENT
• New, higher yielding barleys tend to accumulate N.
• Maintain existing fertiliser practice.
• Aim for 100kg/ha in mid-March.
• Consider pushing some new varieties for yield.