Supplement wrapping information ('wrapped or covered in plastic') is used to estimate the embodied plastic energy and CO2 emissions from plastics. It is assumed that less plastic is used for silage stacks and this is about a 1/3 of that used for wrapping bales.
Leachate from silage stacks can be a point source of pollution; supplement nutrients lost through storage are added to the farm nutrient budget as immobilised nutrients. The "effluent from stack contained" box should only be selected if there is an impervious layer (eg. concrete, plastic etc.) between the bottom of the silage stack and the soil.