22 June 2001

Aiming for more precise cereal seed drilling

A massive reduction in seed

rates, combined with

accurate spacing, has

achieved better cereal crop

development and bigger

yields in preliminary trials

with a new drill from

Stanhay Webb.

Mike Williams reports

CAMBS-based Stanhay is a world leader in precision seeding technology for vegetable crops. Interest in using this expertise to sow seeds for cereals and other extensive crops started six years ago when one of the companys Singulaire drills was used in trials to sow accurately spaced wheat at lower seed rates.

The Singulaire is a vegetable drill and is not suitable for cereals, says Chris Druce, deputy managing director at Stanhay. But the trial results indicated there could be significant benefits from cutting seed rates if the spacing is maintained accurately. Trials have recently continued with a Stanhay Dart precision drill, and the cereal drill that Stanhay is developing is based on the Dart and employs the same metering mechanism.

"The seeding units for the Dart are of a slimline design, which is essential to achieve a suitable row spacing for cereals," says Mr Druce. "It was also designed to stand up to the seedbed conditions that could be expected when drilling cereals, and operate at a similar speed as a conventional grain drill. It also handles other seeds, including sunflowers, sugar beet and peas."

Trial plots for this years harvest were extended to about 30 sites in England and Scotland, working with farmers, farming companies and agronomists. Sowing rates with wheat were as low as 20 seeds/sq m, but the most promising results at this stage are from the 40 and 60 seeds/sq m rates, says Mr Druce. Commercial rates are typically 200 to 300 seeds/sq m, and the 20 seeds/sq m rate is equivalent to about 10kg/ha.

Wheat crops drilled at the lowest seed rates look thin at first, he admits, but the combination of fewer plants and even spacing encourages more vigorous growth, with significantly deeper root development and a big increase in tillering.

"When wheat is drilled at 20 seeds/sq m, the number of tillers is about 30 per plant, and this produces the 600 heads/sq m which is generally considered to be the optimum. The main objective is not to save money on seed. Because plant growth is much stronger, we are also recording improved yields, the crops tend to be healthier – which may have implications for spray requirements – and deeper root penetration may benefit drought tolerance and fertiliser requirements."

Although Mr Druce is waiting until this years harvest before quoting yield benefits, some of the farmers involved in this years trials have already ordered drills on the basis of previous results or because they like the way this years crops have developed so far.

Drills available this autumn will be up to 6m wide and will be rigid, but folding 6m and 8m versions are planned for next year. The drills will consist of individual seeding units with 6.6in or 16.6cm row spacing, and seed is delivered from a front-mounted bulk hopper feeding through a distribution head or from a rear hopper with gravity feed. Stanhay is not supplying the seed hoppers, allowing existing equipment to be used on many farms.

The price of a 4m drill with 24 units is expected to be about £25,000. This includes an electro-hydraulic drive providing stepless control of the seed rate and including GPS compatibility to allow variable-rate control using field map data. Seed Manager optical sensing units for monitoring seed delivery on a unit-by-unit basis are available at extra cost, with visual and audible warnings of under- or over-seeding. &#42