As any horseowner knows, horses generate a lot of manure. All too often, this valuable resource gets dumped in the “pile out back” or thrown in a dumpster to be needlessly hauled to a landfill. Both of these practices have negative environmental impacts. On top of that, they do not make good financial sense.
Composting offers an increasingly popular and cost-effective solution to any horseowner’s manure management situation.
One reason horses make great compost is the simple fact that they are quite prodigious at generating the needed starting ingredient.
A 1,000 pound horse will generate about nine tons of manure per year. In terms of nutrients, that’s approximately 100 pounds of nitrogen, 18 pounds of phosphorous, and 72 pounds of potassium produced annually. That’s a lot of free fertilizer.
Another reason horse manure makes great compost is that it contains the ideal carbon to nitrogen (C:N) ratio. A long-held rule of thumb is that a C:N ratio of about 30:1 is ideal for composting, which falls at or near the average ratio found in horse manure.
The addition of bedding to the compost pile will alter this ratio, depending on the type of bedding used and how much of it gets added to the pile. Wood shavings, a popular bedding choice, are particularly high in carbon relative to nitrogen and will increase the C:N ratio more so than other common bedding options like straw. A little bedding mixed in is fine, as raw manure is often toward the low side of the ideal C:N ratio.
Most stable owners have the perfect place to use the finished compost: their pasture.
To keep a pasture healthy , nutrients (nitrogen, phosphorous, and potassium) must be periodically reapplied as fertilizer. Finished compost is preferred as fertilizer over raw manure because the composting process kills worms and other parasites found in manure and compost is not a breeding ground for flies and mosquitos.
Before applying finished compost to your pasture, it’s important to have yours soils tested for nutrient content. The results of the soils test will tell you how much compost you should apply. Apply too little and the grass won’t have the needed nutrients. Apply too much and the nutrients in the compost won’t be fully utilized by the grass, leaving it free to migrate into surface water via runoff and cause pollution.
If you have more compost than your pastures need, consider giving it away to friends. Some entrepreneurial farm owners have even built profitable businesses selling compost to the local community.
KEYS TO GOOD COMPOSTING
* Build a proper storage area – Ideally your manure storage area should have a concrete floor and be covered by a roof or tarp. A bin system is great for having multiple piles in different stages of the composting process. Locate the storage area at least 100 feet away from streams and other surface water.
* Create air flow – Microbes responsible for the composting process need oxygen to work. Regular turning of the pile is one option. Alternatively, a forced-air system such as “O2 Compost” works well and doesn’t require as much turning of the pile, especially great if you don’t have a front-end loader.
* Manage temperature and moisture – Piles should be kept moist but not wet, having the feeling of a damp sponge. Monitor the temperature of the pile with a composting thermometer. The pile should reach 140-160 degrees F to ensure pathogens are killed.
For more information, there are many excellent fact sheets on composting published by university extension programs across the U.S. and available for free online.
Clay Nelson is Principal of Sustainable Stables, LLC ( www.SustainableStables.com ). He also runs the website FarmandStables.com , where you can see examples of composting systems from real horse farms across the US, including cost information.