Throughout the EU measures have been introduced to control the pollution of watercourses by farm effluent, including liquids from silage clamps, silos or bales.
One of the reasons for the growth in popularity of baled silage is that effluent management requires low capital investment compared to conventional silage. As baled silage is generally made with drier forage, it produces virtually no effluent and no special storage measures are required other than to store bales well away from boreholes and watercourses. However, if the grass ensiled has low dry matter, some effluent is produced and requires management to avoid pollution.
On the other hand, baled silage generates waste film, around 2kg from an eight layer wrap. In some countries this is also subject to legislation concerning disposal or recycling.
Recent studies at the Institute of Grassland and Environmental Research (IGER) in Wales have shown reductions in effluent production from bales wrapped with six layers of film compared to bales wrapped with four layers. Reductions in effluent production can also be achieved by using 750 mm film instead of 500 mm film.