Composting Manure


What goes in must come out. This means horse guardians face a daunting challenge when it comes to manure management. The volume of manure and spent bedding produced at every horse farm can become overwhelming, and results in offensive odors, flies, mud, dust, and an unsightly mess. It’s a universal dilemma, and composting can help.

A closer look at the problem

“A 1,100-pound horse passes manure, on average, seven to ten times per day, adding up to a total daily output of about fifty pounds,” writes Karen Hayes, DVM, author of How to be the Perfect Horsekeeper. A small operation housing only ten horses accumulates almost seven tons of manure in just one month. And that’s just the manure. The muck pile also contains soiled, urine-soaked and wasted stall bedding, which – depending on what type of bedding you use – can double or even triple the volume and weight of stuff that goes onto the pile.”

The actual volume of manure and waste bedding isn’t the real problem. Unmanaged manure is a source of flies and offensive odors. It also results in mud (hoof problems) during the winter months, and ammonia and dust (respiratory problems) during the summer. It adversely impacts our horses’ health and our own. It degrades surface and ground water and harms aquatic life. This is why federal, state and local regulatory agencies are taking a much closer look at horse farms nationwide as a significant source of “Non-Point Source Pollution”.

Manure management options

Alternatives to unmanaged manure piles generally include:

  1. Off-site disposal
  2. Direct land application
  3. Composting

Off-site disposal is a fee-for-service arrangement with a waste hauling company. It involves your having a dumpster or roll-off container situated in a main traffic area. These containers are seldom aesthetically pleasing, and detract from the overall look of the farm. Because waste hauling is typically a franchise business, you will pay the “going rate”, whatever that might be. And rates never go down. In short, off-site disposal can be time consuming and very expensive.

Direct land application has its appeal, especially in situations where few horses live on a large land base. However, even a healthy horse passes millions of potential pathogens in his manure – bacteria, protozoa, fungi, and parasites. As long as his body maintains a healthy balance between the pathogens and friendly beneficial organisms, the potential disease-causers (what we’ll call “nasties”) don’t make him sick, but they’re still there.

“Once the manure and the nasties are on the ground, and the manure begins to accumulate, the nasties start to add up to numbers that could overwhelm even a healthy immune system,” warns Dr Hayes in her book. “Your horse’s ability to resist disease was never designed to stand up to such a concentrated germ load….

“Horses in their natural environment wouldn’t dream of grazing within sniffing distance of a manure pile, and they never stay in one grazing area long enough for manure to accumulate and become a health problem for them. In that way, their natural lifestyle automatically protects them against excessive parasite exposure.

“Compare that to modern horse facilities – even high-end ones with big, beautiful pastures – where horses are confined… With every passing year, the amount of parasite-infested land on the modern horse farm increases, and the amount of pristine land, free of manure, increasingly disappears.” Add to this the potential for degrading surface and ground water and it is easy to understand why regulators are beginning to take corrective action against the entire equine community.

Composting is a win/win option

Composting converts raw horse manure into a clean, high-value product that can be effectively used around the farm or sold for profit while eliminating contamination of land and water resources.

Horse manure compost is an excellent source of macro and micro-nutrients as well as stable organic matter, all of which support healthy plant growth. Compost also retains water extremely well, resulting in improved drought resistance and a longer growing season. The key is to make the composting process systematic and to eliminate pile turning, thereby saving time and money. The answer is to make composting a fully integrated, day to day activity – a part of the farm culture.

In the old days, composting was accomplished using the PhD Method (piled higher and deeper). This was often a one to two-year process and did little to protect surface and ground water or eliminate weed seeds in the “final product”. Today, most people think composting involves turning piles to fluff the material and reintroduce oxygen into the core. What they don’t understand is that the infused oxygen is consumed by the micro-organisms within 30 to 45 minutes, thereby yielding an anaerobic compost pile despite the expended time and effort.

Consider aerated composting

With aerated composting, fresh air (i.e. oxygen) is introduced throughout the mix of materials using an electric blower. The oxygen stimulates the microorganisms and their by-product is heat. In a properly operated compost system, pile temperatures are sufficient to pasteurize the raw material and the oxygen rich conditions within the core of the pile, eliminating offensive odors. High temperatures also destroy fly larvae and weed seeds. Finally, aeration greatly expedites the composting process and lends itself to a true flow-through process, thereby eliminating the “twoyear pile syndrome”. Again, all this takes place without having to turn the pile.

Aerated Static Pile Composting utilizes an electric blower to induce airflow through the pile and thereby help the pile “breathe”. A timer operates the blower which cycles on for three to four minutes and then turns off for 20 to 30 minutes. This system operates 24 hours a day, seven days a week. Within 21 to 30 days, the primary or “active” phase of composting is nearly complete.

Following the active phase, the material transitions into a fungal driven process referred to as “curing”. Most of the textural change to the mix occurs during this phase, yielding a uniform, dark, soil-like product that smells nice and has “magical qualities” according to avid gardeners.

The secret to proper horse manure management is composting; and the secret to composting is that it’s easy when you know what you’re doing.

How it all piles up

A recent study conducted by the American Horse Council estimates the total number of horses in the United States at roughly seven million. The volume of manure from this many horses would fill up the Rose Bowl in Pasadena, California nearly 17 times per month or 200 times each year. Stacked vertically on a football field, from end zone to end zone and sideline to sideline, the pile would stand 7.5 miles high – that’s higher than commercial airliners fly! Again, add to this the volume of waste bedding and you can see this is not a small issue.

Education, not legislation

As horse owners, it is our responsibility to properly manage the manure and waste bedding generated on our farms, and to protect our water resources and the health of our horses. Each of us impacts the world we live in – that is a given. It is up to us to choose whether our impact will be positive or negative. It’s a decision we need to make for ourselves before it’s made for us. And it’s not a matter of “if”, but “when”.

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