Successful composting relies on a proper carbon to nitrogen ratio (C:N); a range of 25:1 to 30:1 is generally regarded as proper. Considering that relative to carbon, a large carcass is much higher in moisture and nitrogen, this is a composting situation where adding excess carbon does not appear to be a threat to success. A well constructed pile/windrow for large mortalities should have a layer of carbon material 18 to 24 inches around the entire carcass. This results in gross C:N, considerably higher than the range described above, but does not appear to inhibit composting in the case of large carcasses. Moisture distribution will be uneven throughout the pile and there are likely to be pockets of anaerobic decomposition immediately around the mortality. While much of the external carbon does not interact with the composting center, it serves a larger role in bio-filtration and insulation. The extra carbon material may also be valuable in absorbing excess moisture from the mortality and rainfall on the pile/windrow.
-Thomas Bass, Montana State University
