The use of plastic film instead of netting when tying round bales for wrapped baled silage

The possibility of replacing net with film to tie large round bales for silage making was investigated. A specifically designed polyethylene film has been developed and used to replace the typical net wrapping. A film-tying device, which was already on the market, was fitted to a variable chamber round baler and used instead of the standard net-tying system. A total of 48 round bales, consisting of half Italian ryegrass and half lucerne were baled following a 2-day wilting period. Half of the bales were net-tied and the other half film-tied. The bales were wrapped with 4 or 6 layers of stretch film and stored outside, half on their ends and half on their curved surfaces, for 180 days. The mechanical, fermentative and microbiological aspects were investigated. The work rate was not affected by the tying method. No evident damage to the film used for tying was observed before or after ejection from the baler or after the mechanical handling using a typical bale squeeze. Plastic consumption for film-tying was slightly higher, but mould on the bale surface was reduced compared to the net-tying method. This study has shown that film-tying could represent an interesting alternative to net-tying when preparing round bales for making silage.

Research highlights
► The stretch plastic wrapping system has shown some limits with regards to sealing efficiency and the non-uniform distribution of the plastic film on the bale surface.
► A specifically designed polyethylene film was developed to replace the typical net wrapping to tie large round bales for silage.
► This tying method increase the number of layers in the areas that are most at risk to damage.
► The surface covered by mould was reduced on film-tied bales compared to the net-tied bales.