Silage is one of the most valuable feed resources on the farm, but its quality can be drastically compromised by one often-overlooked contaminant: soil. While a bit of dirt may seem harmless, even small amounts of soil contamination can have serious consequences for fermentation, animal health, and overall feed value.
In this article, we’ll explore why keeping soil out of the silage-making process is crucial and how to reduce the risk.
Soil: A Silent Saboteur in the Clamp
Soil can carry a range of harmful microorganisms that thrive in the silage environment. The biggest culprits are Clostridia bacteria and Listeria monocytogenes both of which can wreak havoc on silage quality and livestock health.
- Clostridia bacteria, found naturally in soil and manure, disrupt the fermentation process by converting valuable sugars and lactic acid into butyric acid, ammonia, and other unwanted compounds. The result? Silage that smells bad, has low nutritional value, and is often rejected by animals.
- Listeria monocytogenes also enters via soil and can survive in poorly fermented silage. This bacteria causes listeriosis, a serious and often fatal disease in sheep and cattle, particularly during late pregnancy and early lactation.
More Than Just Microbes: The Ash Effect
Another issue with soil is the increase in ash content. High ash levels in silage signal contamination with soil or dirt, which dilutes the true feed value. This non-nutritive material reduces energy content, affects palatability, and can cause unnecessary wear on feeding equipment.
How Soil Gets into Silage
Soil contamination can occur at several points in the silage-making process:
- Cutting too low with the mower, especially on uneven ground
- Harvesting in wet or muddy conditions
- Dirty machinery or trailers
- Dragging soil into the clamp during filling
- Using soil to weigh down silage sheets
Each of these risks is preventable with good management and attention to detail.
Practical Steps to Keep Silage Clean
To reduce the risk of soil contamination:
- Lift mower height slightly to avoid scalping the soil surface.
- Wait for dry conditions before mowing or harvesting to minimise mud pickup.
- Keep trailers and loaders clean, especially wheels and buckets.
- Avoid driving across the clamp with dirty tyres.
- Use clean silage sheeting and weighted bags (not soil) to seal the clamp edges.
- Manage headlands carefully, as these are often the dirtiest parts of the field.
The Bottom Line: Better Silage, Healthier Livestock
Clean silage means better fermentation, higher feed value, and healthier, more productive animals. Avoiding soil contamination doesn’t require major investment just good attention to harvesting practices and clamp management.
At a time when feed costs are high and margins are tight, making high-quality silage is more important than ever. Keeping soil out is one of the simplest and most effective ways to protect your investment.
