Why do winter barley crops continue to disappoint?
The final yields achieved by winter barley crops was discussed at a recent crop walk on the south Co. Down farm of Shaw Hanna, hosted by College of Agriculture, Food and Rural Enterprise (CAFRE).
Teagasc tillage specialist, Shay Phelan, took part in the discussion.
He explained: “We have an unfolding scenario within which many growers apply inputs to winter barley crops, which should see final yields coming in at around 4t/ac.”
“However, in most instances this potential is not realised.”
The Teagasc representative went on to confirm the yield-robbing power of Barley Yellow Dwarf Virus (BYDV) infestations in this context.
“BYDV can reduce yields by to 1.5t/ac," he said.
"Ongoing research at Teagasc is seeking to identify the specific aphids that carry the BYDV virus under Irish conditions and how best they can be controlled.”
Simon Best, who farms in the Newry area, indicated that he now sows BYDV tolerant varieties of winter barley as a matter of course.
In part, this reflects the early September-sowing dates selected within the business.
Meanwhile, manganese deficiency has been identified as a key growth limiting factor within many winter barley crops established across the island last autumn.
Phelan said: “Protecting the tillers that barley crops have produced at this stage is the key to maximising final yields.
“So it is important that growers address the manganese issue right now while also ensuring that crops’ full fertiliser requirements are met before the beginning of April.
“Taking this approach will ensure that the tillers will have access to the nutrition they need during the period when maximum levels of growth are taking place.”
Disease control strategies for winter barley focus on two challenges; rhynchosporium and ramularia - in that order.
Where disease pressure is low, a two spray programme can be considered: at the late tillering/stem extension stage; and then again at awns emerging.
Winter barleys that are following on from a previous barley crop are at the highest risk of succumbing to disease pressure.
Plant growth regulators (PGRs) should only be applied during periods of active growth. Growers should also be conscious of significant diurnal (day/night) temperature swings.
Trace elements can be added to a PGR tank mix.
Weed control in a number of winter barley crops is reported to be patchy.
Playing catch up with a herbicide now will not deliver full control where populations of annual meadow grass are concerned.
