If its old silage, I think I'd want to get a bit more life into it before I'd use it as mulch. Is there any way you can turn it into an active compost pile first, and then after a couple of weeks, use it as mulch? If you were to mix it with some greens and let them rebuild the microbial community, my hunch is that it will be much more beneficial to your soil.
Post Tenebras Lux
Until further notice, we will celebrate everything.
Are you okay? You look a little big. Maybe this tiny ad will help: