10 April 1998

A good start key to linola

By Louise Impey

GOOD establishment is the key to high yields of linola, advises Nickersons Seeds technical manager, Alastair Moore.

That means getting seed-bed conditions right and providing protection against early flea beetle attack, he stresses.

"Linola can be grown on most soil types providing a good seed-bed can be achieved," he says. "A pH of 6.0-7.0 is recommended, so soils below pH5.5 should be limed."

The need for a fine, firm seed-bed means autumn ploughing is recommended, followed by a minimum number of spring ultivations. Rolling before or after drilling can help by retaining moisture close to the soil surface.

Drilling should take place between mid-March and the end of April. "The soil temperature has to be rising, or emergence will be delayed", warns Mr Moore. "But late drilling can subject the crop to drought."

In contrast to conventional linseed, the seed rate for linola is reduced to 50kg/ha (45lb/acre) due to its smaller size.

"Seed should be drilled to an even 0.5in depth," he adds. "If it is sown too deep, say below 1in, it may not come up."

Vitavax RS (carboxin + thiram + lindane) protection is essential for flax flea beetle control. Mr Moore points to ADAS trials which show this is the most effective seed treatment for this purpose. But a cypermethrin spray may also be required at emergence if flea beetle numbers are high, he adds.

"Fertiliser requirements are low. Although much depends on the soil index, most crops needs 40kg/ha of P, 50-60kg/ha of K and 80kg/ha of N."

Linola grown on sandy and shallow soils on chalk needs less nitrogen in the seed-bed and more as a top dressing. In contrast, medium and clay soils should have more in the seed-bed to avoid lodging.

Good weed control is important because linola is not a competitive crop," advises Mr Moore. "There is an increasing number of agrochemicals cleared for use on it, but growers should always check the manufacturers recommendations."

He prefers post-emergence herbicides to the use of pre-drilling or pre-emergence materials. "Waiting until the crop is 6-8in high will give growers a good idea of the weeds they are up against.

"Then they can use a product such as Ally (metsulfuron-methyl) or Basagran (bentazone) for broad-leaved weeds, and any of the approved graminicides for grass weeds." He admits cleavers may prove difficult to control.

The benefits of growth regulator use on linola are unclear, Mr Moore maintains. "Trials results have been very variable. A vigorous crop on very fertile soil may need an application to prevent lodging."

Insecticides and fungicides are rarely necessary, he stresses. "If it is wet, a fungicide at the end of flowering may be needed for botrytis and alternaria."

Harvesting is by direct combining and the use of a desiccant. "The key to a successful harvest is to apply the desiccant when the seed is rattling in the pods and then leave the crop for up to three weeks.

"Plenty of water and a large droplet size are important with desiccation – nearly all the harvesting problems we encounter are due to green straw," he says. "That is when wrapping starts to occur."

Crops are usually cut by the end of September. Mois-ture content can vary from 7% to 15%, though the maximum for storage and marketing is 9%. Yields in 1997 averaged 2.5t/ha (lt/acre).

"Linola deteriorates rapidly in store at a high moisture content," warns Mr Moore. "It is easy to dry and, if required, should be dried soon after harvest. Both continuous flow and batch driers are suitable."

New edible linseed lines demand some changes to established linseed management to make the most of the premium-earning crop.

LINOLA SOWING NEEDS

&#8226 Firm, fine seed-bed.

&#8226 Flea beetle control.

&#8226 Reduced seed rate.

&#8226 Beware deep drilling.

&#8226 Low fertiliser input.