Ultra-low seed rate leads to a higher yield

16 August 2002

Ultra-low seed rate leads to a higher yield

By Wendy Short North-east correspondent

GROWERS in the north of England have been cautious about cutting winter wheat seed rates for fear of yield losses. But one North Yorks farmer has seen a yield improvement of at least 20% by moving to early drilling and rates as low as 120 seeds/sq m.

Before 1999, Mike Webster was drilling about 600 seeds/sq m and getting an average yield of 7.4-8.6t/ha (3-3.5t/acre). Since making the drastic cut in rates he has seen yields rise to 9.9-11.1t/ha (4-4.5t/acre).

An additional variable cost of £6/ha for an extra aphicide treatment on very early-sown crops is offset by a similar saving in seed inputs, he says.

The most dramatic results have been on the light soils at Staynor Hall Farm, Selby. The new regime has meant yields from sand now equal those from the heavier land.

Early sowing is a key element to getting the best results. "It is absolutely essential the seed makes contact with moisture and starts germinating straight away so I follow with the press soon after drilling," says Mr Webster.

"However, once the crop is established it is less likely to suffer drought stress near harvest, because roots go down to a greater depth. That is where the main yield improvement comes from."

The additional aphicide treatment is also an important part of management.

"With early-drilled crops the foliage starts to cover the ground just when the aphids are looking for somewhere to hide during their winter migration," explains Mr Webster. "Without treatment it is possible to lose 3t/ha due to barley yellow dwarf virus."

He normally goes for a quick knock-down using a full-rate application of cypermethrin. That is followed with Sumi-alpha in October, which tackles any aphids in later-sown varieties.

Mr Webster warns that the large number of tillers (often 30-40/plant) in an early-drilled crop can produce a potential hotbed for disease. As a precaution, half-rate Erysto (quinoxyfen) is usually applied to protect against early mildew in Claire.

Varieties sown slightly later, such as Consort, Savannah and Charger, receive a conventional strobilurin/triazole programme at T1 and T2 stages.

Financial savings are important, says Mr Webster. But drilling in early September also gives him a three-week window to get the crop in. In theory, that means the wheat is safely in the ground before the worst of the autumn weather takes hold.

He admits it took two seasons before he was fully convinced of the advantages. His first attempt in 1999 was half-hearted and sowing 250 seeds/sq m where he was advised to use 120 failed to produce the desired result.

"Yields were only equal to and in some cases slightly lower than in previous years. There were too many plants and at one stage the crop looked as if it might lodge. In 2000, I got nearer the mark on seed rates and that made up my mind."

One of the few snags is sourcing seed in the early autumn. "We are drilling before most seed crops have been combined. Trying to find yearling seed is not always easy.

"Managing an early-drilled crop is not that difficult as long as the right varieties are chosen," he concludes. "It is important to get a slow-maturing variety so the internal ears do not suffer from frost-damage in November/ December. Apart from that, it is mainly a question of having the confidence to give it a try." &#42

Autumn sowings 2001

Area Variety Seeds/ Sowing sq/m date

61ha Claire 125 1 Sept

32ha Savannah 250 End Sept

30ha Consort 250 End Sept

23ha Charger 300 Oct (ex SBt)


&#8226 283ha wheat, barley, OSR, sugar beet and spring beans.

&#8226 4-5m above sea level. Blow-away sand to rich loam.

&#8226 Seeds rates down to 120 seeds/sq m.

&#8226 20% yield boost.

&#8226 Main yield increase on light sand.

&#8226 Moisture at sowing crucial.

&#8226 Home-produced cereals feed 650-sow breeding and fattening herd.

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