Cereal growers may need to increase their seed rates to maximise yields this autumn, particularly when drilling late, as establishment and tillering are often overestimated.

Andy Hutchison, agronomist at advisory group Farmacy, suggests growers should review their seed rates and establishment methods to maximise yields.

Most winter wheat generates only 1.8-2 tillers/plant on average, so seeds rates need to be adjusted through the autumn to optimise yields.

See also: Variable seed rates show some big benefits

For September wheat drilling, the target should be 150-200 plants/sq m, while for October-sown wheat the aim is for 250-300 plants/sq m. 

In terms of winter barley, higher seed rates are needed and Mr Hutchison recommends at least 300-350 seeds/sq m for autumn sowing.

Time to tiller

“There’s more leeway for lower seed rates with September-sown wheat, as establishment typically averages about 85% and plants have more time to tiller,” said Mr Hutchison.

However, establishment falls to 60-65% by mid-October and perhaps just 50% by November/December, with much less tillering capacity, he added.

In-field variations, such as soil types and weed pressure, can also result in uneven establishment, highlighting the value of variable seed rates and precision farming systems.

Ten years of variable seed rate work shows average seed rate increases are 35-50%, but crops and yields will be more consistent, with the greatest benefits on the most variable fields, Mr Hutchison added.

Clear benefits 

Cambridgeshire grower Daniel White has been using the Omnia precision farming system for the past two seasons to map and manage in-field variations on his 260ha farm near Bottisham, just east of Cambridge, and is seeing clear benefits on crop consistency.

“It’s our second year using variable seed rates and it has definitely made the established plant population more even across our fields,” said Mr White.

“Once you have good, even establishment, it helps take out the variability of managing the crop through the season,” he added.