What factors will prevent a good fermentation?

• Introducing soil into silage – this is a particular problem below 25% DM when the clostridia bacteria from soil contamination can flourish and turn a potentially good silage into a very poor one with high DM losses (clostridial secondary fermentation).
• Late or heavy fertiliser application – assume 2.0 units N per acre (2.5 kgN/ha) utilised per day of growth and apply no more than can be taken up before the planned cutting date.
• Late slurry application – do not apply less than 10 weeks before cutting if surface spreading. If injecting, applications up to two weeks prior to cutting should be fine.
• Application of dirty water or silage effluent – do not apply to silage ground.
• High grass nitrate-N levels, ie above 1000 ppm (0.1%).
• Bad sealing – if the sheet or wrap is damaged or of poor quality, air can get in.
• Over-rolling wet young grass – with high quality direct cut or minimal wilted material under 20% DM, condition lightly, chop longer and roll sufficiently to level and tidy only.

Usually it is a combination of several of these factors, rather than any one, that lead to a poor fermentation.