8 September 1995

Good management at clamp key to quality

TOP quality maize silage is down to good clamp management. This view is taken by Keith Blenkiron, winner of the 1995 Maize Growers Association silage competition.

Mr Blenkiron grows 49ha (120 acres) of forage maize at his 100ha (250-acre) Lark Hall Farm, Northallerton, North Yorks. He uses two varieties harvested separately at 30% dry matter.

"We want a balance between quality and yield, so we use Ema, a short, very early maturing high grain variety, and Janna a tall, medium early that provides us with the bulk," he says.

The two silos used are within a single building and have a concrete base, walls up to 3.6m (12ft) and can store up to 2000t of silage.

"The contractor has an eight-row harvester which enables us to get the crop into the clamp quickly," he says. "We aim to have the crop sealed within about a day, so that it does not heat up which is a big waste factor."

This year Mr Blenkiron hopes a crop processor on the forage harvester will crack the kernels so that the nutrients are more readily available to his 480 beef cattle.

"Using a contractor with first class machinery also means we can get the chop length down to about 0.5in – the shorter the chop, the easier the crop is to consolidate.

Mr Blenkiron says it is important to consolidate the crop as it is brought into the silo. "There is no point in filling a silo and driving a tractor over the top, then hoping that the material at the bottom will be compressed," he says.

His crop is consolidated continuously between loads using the contractors heavy loading shovel. In all each silo is consolidated for about four hours after filling.

Broiler litter

It is then sheeted with a shoulder sheet, that extends 0.6m (2ft) down the clamp side, and a cover sheet. "We make every effort to ensure the sheet is in close contact with the crop and use broiler litter spread evenly at a depth of about 0.5in across the entire surface of the sheet instead of tyres.

"It is ensuring close sheet contact that promotes good anaerobic conditions for the ensiling process rather than just weight," says Mr Blenkiron. He uses new sheets when necessary and poison baits to prevent sheet damage from vermin.

As for forage additives, he considers salt unnecessary when clamp management – particularly the sheeting – is right. "But we do use an additive to promote aerobic stability," he says.


&#8226 Chop length should be about 1.2cm (0.5in) and no more than 2.5cm (1in).

&#8226 Consolidate maize as each load is brought into the silo.

&#8226 Harvest to sealing clamp should take no longer than a day.

&#8226 Ensure sheets are in contact over the entire maize clamp.

MGAs 1995 maize silage winner Keith Blenkiron (right) tells judges his secret for top quality silage.