There are many things which should be considered when looking for good quality silage in the clamp. Not only should it be compacted and consolidated well, but the area should also be appropriately and quickly sheeted and weighed down. It is also important to ensure that the silage isn’t contaminated.

What Is the Process for Silage in the Clamp?

Bacteria on the cut grass produce lactic acid using sugars which are present in the plant from photosynthesis. This then ferments the grass into silage. The low pH produced prevents the harmful bacteria from reproducing, helping to maintain the quality of the silage. It’s important to keep the air out, allowing the silage to stay at a stable pH.

Secondary Fermentation

Secondary fermentation can be caused by multiple different factors. One cause of secondary fermentation is when the clamp is not correctly sealed, it also occurs when the grass has soil contamination (clostridia). Another cause of secondary fermentation is when the sugar content of the cut grass is insufficient, this happens when the grass has been left to wilt for too long or when it is cut at the wrong time of day.

Clostridia uses proteins in the herbage for fermentation, producing butyric acid and ammonia. This results in a slow drop in the pH and therefore inconsistent silage with high in-clamp losses. The silage which is affected by clostridia may appear a dark brown colour with a slimy texture, it being likely it will have a vinegar-like scent. 

Should You Bale or Clamp the Grass?

When considering whether to put your grass in a bale or clamp, it is important to consider the positive and negative impacts that these options can have. 

Bales: Pros vs Cons

Pros  

• They are consistent, the complete fermentation leading to less wastage
• Bales are convenient to use as they can be transported and fed in the field
• They are flexible in timing as making bales and be done on a field-by-field basis rather than all at one
• It can be a quicker process than clamp silage due to fast fermentation
• Bales can be target-fed

Cons

• Bales use a greater amount of plastic, which is both costly and produces negative environmental impacts

Clamp: Pros vs Con

Pros

• Silage in the clamp is much less costly to produce
• They are quicker to feed as there is no need to use a telehandler to open the bales 

Cons

• There are greater losses from effluent, and it is important to have the ability to store it
• There is also a risk of the face going mouldy when the clamp is the incorrect size or if the silage is dry

Preparing the Clamp

It’s important to remove any material from the clamp and make sure the floor is draining thoroughly. Side sheets should also be placed along the walls to ensure the clamp is fully airtight.

The clamp should be filled rapidly and rolled in shallow, even layers to ensure thorough consolidation. Not only will over-filling the clamp result in poor consolidation, but also low-quality fermentation and high in-clamp losses.

As soon as the clamp is consolidated, the sheets should be put on the clamp. The sheets should consist of one ‘clingfilm’ like layer, followed by a protective sheet. It is important to ensure that the clamp is fully covered by airtight sheets. 

Any holes in the sheets will allow air and water into the clamp, resulting in waste. To prevent this, the sealed grass can should be weighed down with heavy objects, such as tyres, nets, or bales.