Permeable covers are used to reduce odors and emissions from manure storage structures. Permeable covers are materials such as a natural crust, straw, ground corn stalks, as well as expanded clays, ceramics and ground rubber that lie directly on the surface of the stored manure and provide a physical barrier between the manure and the surrounding air.

This fact sheet is part of the Air Management Practices Assessment Tool (AMPAT) developed at Iowa State University and funded by the National Pork Board. Additional resources can be found on the AMPAT web site.