24 July 2002

Disappointing six-row performance explained

SEVERAL reasons could lie behind the lower than expected specific weights being reported in a widely grown six-row winter barley.

Camgrains Philip Darke reports Siberias quality as "poor, very thin, low specific weight and high screenings."

Only a few samples have been seen so far in a "stop/start" harvest, says Norfolk-based Stephen Howlett of Grainfarmers. "Everyone was hopeful of Siberia, but it is struggling to make 63kg/hl." He blames earlier drought.

By contrast Wilts-based grower David Hues believes wet weather during grain filling is largely responsible for the 61kg/hl from his Siberia off heavy clay over chalk. Last year he achieved 66-67kg/hl.

Banks Cargill samples from Hants and Dorset have ranged from 66kg/hl to as low as 57. "But there is no wholesale problem yet," says the firms Jonathan Hoyland.

Dalgety agrees that the French-bred varietys specific weight, rated by NIAB at 63.4kg/hl, is not as good as it was last year. The firms Mike Jeffes says reduced seed rates may be another reason.

The variety tends to perform best when most output comes from the main stem, as in spring wheat. Lower seed rates produce too many tillers, he explains.

"All our trials indicate that a rate of around 400 seeds/sq m rather than 250-300 gives better bushel weights as well as better yields." An ARC trial sown at 450 seeds/sq m produced 65kg/hl, but 250-300 gave only 61, he notes.

Masstocks David Langton says take-all could be playing a bigger role than normal. "Take-all is reasonably bad this year, but you dont see the whiteheads in barley." &#42

Quantity, but not quality: Siberia barley pours off the combine at the Wentzel Estate, Herts. "Specific weights are only 62kg/hl… but the 9.5t/ha yield more than makes up for the loss in quality," says farm manager, Tim Whitehead.