Building field silage clamps with Silostop®

Monday 31 July 2017

The good growing conditions of 2017 have resulted in high yields of both grass and whole-crop. The outlook is positive for a good maize harvest. As a consequence, farm silos are fuller than usual and many farms and AD plants are looking to utilise field clamps to hold extra tonnage of silage.

Here are some top tips from Silostop® for building field silage clamps.

1. Know the law.

The relevant UK regulations are the SSAFO regulations.  In England and Wales they are the Water Resources (Control of Pollution) (Silage, Slurry and Agricultural Fuel Oil) Regulations 2010 (Amended 2013). DEFRA guidance:

“You must not make or store any silage, or unwrap baled silage, within 10 metres of inland or coastal waters. In addition, you must not store field silage within 50 metres of a ‘protected water supply source’. That is any place where water is abstracted (taken) for any of the following purposes: Human consumption, use in farm dairies, human food preparation.

Ask the Environment Agency about protected water sources or use the ‘what’s in my back yard’ map to check your local area.

For silage stored as ‘field silage’ there must be no construction works, e.g. walls or earth banks, and topsoil must not be disturbed.

If you make field silage or non-baled bags you must:

  • Choose a suitable site – e.g. if you store silage in a non-baled bag in your farmyard you must make sure you can contain any drainage
  • Notify your local Environment Agency office at least 14 days before you first use the site

Use form WQE4 to tell the Environment Agency if you intend to make or store field silage. Give at least 14 days’ notice. Send the completed form to your local Environment Agency office.”

2. Ensure good access.

You will need good access to the site with tractors and silage trailers, loaders and packing tractors. Aim to minimize soil contamination. Feed out during the following summer when ground conditions are suitable. Plan vermin and weed control for up to 10 months.

3. Build the clamp safely.

Drive-over piles are safer than push-up piles with steep sides. Clamps can have a flat centre and then appropriately sloped sides. Pack from side to side and avoid steep slopes - maximum 1 in 3.   1 metre centre height = 3 metres width from centre to give safe side slopes for rolling.

Losses during storage are greatest at the sides where silage density is lowest. Make sure to pack the sides as densely as possible.

4. Make a long narrow clamp to give rapid feed-out progression and minimize aerobic spoilage.

The target progression rate, speed of movement from front to back of clamp, is 1 metre a week in winter and 2 metres a week in summer.

5. Cover immediately after filling with Silostop® film to reduce losses.

Drive-over piles have a higher proportion of the total mass within the outer 1 metre than bunker silos. Silostop® oxygen barrier film is proven to reduce dry matter losses in the peripheral areas of silos by up to 50% compared to conventional polyethylene film.

Silostop®Max rolls of 150/300m length allow easy covering of large clamps, and Silopatch tape can be used for securing joins between sheets of film.

6. Protect Silostop® film with netting and gravel bags. 

Cover Silostop® for protection with Silostop® Open Nets and then weigh down with Silostop® gravelbags. For long, narrow clamps place a line of gravelbags on the apex lengthways, and then rows every 5metres side to side. A 15 to 30 cm layer of sand and/or soil or gravel bags placed end-to-end is an effective way to anchor film sheets and nets around the perimeter of the clamp.  Wrapped bales can also be placed around the base of the clamp to add extra weight.

Inspect the clamp regularly for physical damage to the covering film by birds and rodents.  Repair holes with Silopatches.7.

7. Feed out carefully

Avoid scraping up soil when unloading field clamps.  Soil can damage cow health and stones can damage machinery in AD plants. The silage is best left until the following summer when ground conditions are suitable for feed-out. 

For more information about field silage clamps please contact

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