Composting for Horses
I am planning on running an operation that contains around 15 horses on average. I am in love with the idea of composting, but I can not find any literature that tells me how large I should make my bins or how many I should plan on using. Any ideas?
Horse manure composts fairly well. The raw manure has a C:N ratio that is close to ideal for composting. The biggest issues are the volume of manure produced, keeping it aerated and the additional bedding. Some composters do not like to use animal manures because of the additional odors. But, a well balance compost process should not add an odor problem. The manure has all of the microbes to help it get started composting and old compost can be used as starter for a new pile. Leaching or drainage from the pile can make trouble for you. Protecting the piles from wet weather should be done. Control when and how water is added.
The volume of manure that we expect from a horse is about 3/4 of a cubic foot per 1000 lb horse. Cool weather times will slow the composting process and I usually recommend sizing everything to store 6 months of production. So, for the 15 horses you would need 12 cubic feet per day stored with a minimum for bedding added. I think you will need to break up the road apples and the small amount of bedding will help the stack stay aerated. Flipping the piles every few days will help to maintain that aerating. A composting thermometer will help you keep track of the process. The odors from the piles will help track the composting process as well.
The following guide has the basics of the composting process to get you started. Making and Using Compost
The reference materials mention at the end of the guide are available from your local Extension Center in Boone County.
There is some composting research being done out at the Bradford Research Farm, SE of Columbia.