5 July 2002

Seed rate caution urged

ULTRA-LOW seed rates have no place on Scottish farms. But there is scope to cut seed costs and improve spring management by reducing rates by up to 25%.

Three years of SAC trials followed by two years of HGCA-funded work show about 300seeds/sq m (1.27cwt/acre) is optimum for early October sown wheat, says Lawrence Morris of SAC Aberdeen. Any lower and frost heave can hit plant counts hard, even if slugs have not already taken their toll.

"Last winter we had two lots of cold weather, with temperatures down to -12C, and the lower seed rate plots suffered most from frost heave," he says. Whether that was due to less rooting or less plant cover is unclear. But the result was far too few plants to produce a viable yield in plots of Claire sown at 40, 80 and 160 seeds/sq m.

That was despite good initial establishment in favourable seed-beds free from slugs and changes to spring N and pgr use. "We just havent been able to get the thin crops to compensate enough," says Mr Morris.

"Its clear that there is scope to come down from 4-500 seeds/sq m, which is normal for the area, but you have to consider the risks."

Farmer and HGCA R&D committee member Jim Arbuckle from nearby Dunecht agrees.

"You dont want to be too near the cliff edge with seed rates. At 80 seeds youre over it and 160 is right on the edge. Crops behave very differently up here from East Anglia. They just dont put on the lush spring growth and tillering that they do in the south." &#42