Does it matter if it's green or black?
Since the introduction of balewrapping in the UK and Ireland, the vast majority of silage bales have traditionally been wrapped in black film.
This is not, however, the case in some other countries, where either green or white films are the colours of choice. There are various influencing factors in deciding which colour to use.
Whilst all of bpi.agri’s balewrap films are protected against the effects of UV radiation, if used in the hot sunny climates found in some foreign countries, black film will absorb much more heat than will paler, more reflective colours. This can produce high temperatures within the bale, which in turn may adversely affect silage quality, by providing more favourable conditions for spoilage organisms to develop. Also, in very high temperatures, the oxygen permeability of black film will be higher than that of white or green. This will be most pronounced in countries such as Australia, Canada and South America, where little black film is used.
In the UK’s climate, black balewrap film is known to seal far more quickly than paler colours. This is because black film absorbs heat more easily and so assists the production of an airtight well-wrapped bale which in turn will produce better quality silage.
Even after 20 years of balewrap sales, black film still outsells green film by 3 to 1 in the UK reflecting the overall satisfaction farmers and contractors find in using this colour.
The majority of green or white film sold in the UK and Ireland is used for wrapping haylage bales, where users like to differentiate their product from silage. Also, because of the much higher dry matter levels of haylage, it is more prone to spoilage, and there is more of a case for a film colour which helps to keep bales at a lower and more constant temperature.
However, whether wrapping silage or haylage, it is well documented that by far the biggest benefits are to be derived from providing an improved oxygen barrier around the bale. To ensure this is the case, haylage has, for some years now been wrapped with between 6 and 12 layers of film. With conventional silage, it therefore makes much more sense to invest the small extra cost of applying two extra layers of black film, rather than changing to a different and more expensive green or white alternative.
John Lancaster, Commercial Director at bpi.agri comments “Bpi.agri appreciate that all three colours have benefits in different situations so we like to offer customers a choice when it comes to colours and sizes. Having supplied bale wrap for over 20 years we still find that demand for black film in the UK is far greater then the other colours, which we put down to a combination of factors including climate, landscape aesthetics and tradition.
DATE: 17/07/2006
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