Advice for creating temporary field clamps for maize

Clamping maize in a field could be an option for farmers to avoid overfilling permanent structures or making a mess on roadways – but it requires careful planning.

Hefin Richards of Rumenation Nutrition Consultancy says temporary field storage is preferable to overfilling walled clamps to avoid wastage and excessive structural pressure on clamp walls.

See also: Maize dry matters fall 3% in varied year

“Overfilled clamps generally have poor shoulder consolidation, since it is unsafe or difficult to roll because the forage is much higher than the walls,” he says.

However, he points out that field clamps must meet regulatory requirements (see “Regulatory requirements for field silage”) and, therefore, need careful planning and consideration.

They are not permitted in Scotland, for example.

Clamp construction and key considerations

Hefin says the most important factors are location and crop dry matter (DM).

“Effluent loss should be minimal if forages are high in dry matter (more than 30%).

“You need to choose a field with good soil structure and locate the silage in an area of the field that gives easy access for filling and emptying the pit.”

He says soil type should ideally be free-draining, and a grass-covered surface is preferable.

Base sheets and hardcore are not permitted. However, if the forage is clamped in a stubble field, a layer of straw can be used to minimise silage-to-soil contact.

Hefin suggests removing this layer and using it as farmyard manure.

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When clamping in the field, Hefin suggests working with a narrow silage face to allow for more rapid movement through the clamp.

“This will minimise the risk of aerobic spoilage, which may be an issue with a large surface area face on a large clamp,” he adds.

Provided the clamp is well-consolidated and sealed, Hefin says there is no reason DM losses should be higher in temporary field clamps.

“Losses would be much lower than a poorly consolidated, overfilled clamp,” he suggests.

Farmers should use the clamp during the summer when conditions are drier, to minimise field damage.

“The drier weather will reduce soil damage, ruts, and the risk of contamination and wastage,” he points out.