1 September 1995

Could seaweed dip boost early spuds?

DIPPING seed potatoes in a seaweed concentrate before planting could boost early season growth and help plants resist nematode attack.

That is the startling evidence to emerge from field trials conducted by Farmura, the UK importer of the South African seaweed product Kelpak.

"We knew from field trials last year that dipping seed in a solution of Kelpak and other growth hormones can boost yield," comments Farmuras Brian Herbert.

The effect is thought to come from the hormones in Kelpak stimulating vigorous early root growth.

Emergence enhanced

Treated crops emerged 10 days ahead of untreated ones and maintained an advantage throughout the season. The programme included standard foliar treatments of 4 litres/ha (2.8pt/acre) of Kelpak in early June and a further 2 litres/ha (1.4pt/acre) two weeks later.

Although no large-scale harvesting comparison was made, hand-dug row lengths suggested a 13t/ha (5.4t/acre) yield advantage on the blowing sand farm in Yorkshire, says Mr Herbert. Another site indicated an 8.6t/ha (3.5t/acre) yield lift.

That suggests that the £40/ha (£16/acre) invested in dipping and foliar spraying can be "very cost effective", comments Farmuras Michael Farrant.

This year the trials were extended to grade D nematode-infested land on Alan Kerridges Mill House farm at Stamford Bridge, York.

"The theory is that the growth stimulants in Kelpak produce a stronger root system, which is better able to withstand nematode attack physically," says Mr Farrant.

The blowing sand site had nematode counts of 57 cysts/100g of soil and 30 eggs/g of soil, with 75% of the population as G pallida. Planting was on Apr 28 with once grown, unchitted Cara seed.

By late June the untreated area was suffering nematode attack. But the treated crop, which also received standard foliar treatments, appeared unaffected.

Root and soil samples were sent to nematode specialist Colin Flemming at the Department of Agriculture for Northern Ireland in Newtownabbey, Co Antrim. His analysis showed just 16 cysts/g of root from the treated crop, compared with 60 cysts/g in the untreated crop.

Results from field trials laid down on nematode-infested and uninfested land in Northern Ireland by DANI are now keenly awaited. &#42