As a life-long horse owner and environmental educator, composting horse manure was something I knew about but didn't fully appreciate until I first brought my horse home to live on my small property. That's when I came face-to-face with one of the less appealing realities of stable management—manure, and lots of it.
Composting manure was the solution to the equine "output equation" anyone who has cleaned a stall is familiar with : A single horse produces about 50 pounds of manure per day, which adds up to more than eight tons per year. Add to that the eight to 10 gallons of urine a horse generates, plus the wheelbarrow or more of bedding used each day, then multiply that by the number of horses on a property. Obviously, it's not long before a manure mountain is crowding you out of your acreage.
The best way to keep this mountain of waste from becoming unmanageable is to compost. Not only does it solve the problem of accumulating waste, but horse manure compost is a useful, even valuable, product to use on the rest of your property.
You don't have to spend much time around manure to grasp the many problems it causes when it's not managed properly. Odor and the "ick factor" are just the start---raw manure is the ideal breeding ground for stable flies and other pests. Runoff from manure piles can also cause water quality issues for creeks and wetlands as well as for drinking water, a serious concern if you have your own well. Many states and counties have ordinances that place strict controls on pollution issues like these.
Many horse farms dispose of their manure by spreading it over pastures. But that practice can be problematic. Horses need to be kept away from freshly spread grazing areas because they can pick up parasite larvae that hatch in fresh manure. Also, raw manure is high in nitrogen compounds that can "burn" plant roots if applied in too high quantities, and the nitrogen runoff can be damaging to nearby creeks and ponds. Spreading is an option only at certain times of the year---leaving you with growing piles when the weather is too wet or the ground is frozen.
Composting manure eliminates these problems. Organic matter decomposes no matter what the circumstances. But anaerobic decomposition, which means in the absence of oxygen, does not destroy dangerous organisms such as E. coli, and it produces high levels of odorous and noxious wastes, such as ammonia gas. (In fact, systems that capture methane gas for use as fuel utilize anaerobic digestion of manure.)
In contrast, composting is the aerobic decomposition of waste---it occurs in the presence of oxygen and a little moisture. This process offers several advantages over both anaerobic decomposition and the spreading of raw manure:
• Faster decomposition. With the right balance of air and moisture, the beneficial microorganisms speed up the process of breaking down waste.
• Fewer pests and parasites. The microorganisms that create compost generate tremendous amounts of heat---enough to kill fly larvae, parasite eggs and weed seeds as well as disease-causing bacteria, such as salmonella and E. coli.
• More effective fertilizer. In raw manure, nitrogen and other compounds are in chemical forms that dilute in water and run off easily. Composting, in contrast, binds nitrogen into organic forms that remain in the ground longer and are more readily available to plant roots.
• Less odor. Composting also produces less of the noxious gases that cause serious smells around unmanaged manure piles. A properly managed compost pile should smell earthy and pleasant.
• Smaller volume. Composting stall waste reduces the total volume by about 50 percent, and the resulting dark, crumbly material is lightweight and easy to handle.
Finished compost is a marvelous soil amendment for gardens, landscapes and pastures. It is infused with micro- and macronutrients that work in a time-release fashion, and it adds "life" to soils in the form of beneficial bacteria and fungi. Research has shown that compost makes plants healthier and more disease resistant and that just one application can have benefits lasting five or more years. Compost also helps the soil retain moisture, which is very important during a drought.
6 STEPS TO EFFECTIVE COMPOSTING
Creating compost takes some time and attention, but most small-acreage horse owners I've worked with have found that the process is easy to manage.
Your first decision will be whether you want to work with a bin or a pile. To generate the appropriate amount of heat, which develops in the center of the pile, the waste has to be piled a minimum of three to four feet high and wide, at least the size of a washing machine. A bin is a small walled enclosure, typically about four to eight feet square, that holds the waste in place and allows it to be stacked high. A typical composting system might include at least two to three bins---you'll actively add waste to one while the others are "cooking."
Smaller bins can be managed without tractors or expensive equipment, but larger stables might need a sturdier structure with stronger walls, a roof and a cement floor. Bins are organized, make for more efficiency and they "hide" the waste. However, they do cost money. Composting can also be done simply with open piles.
Managing compost essentially means treating the manure pile like a living organism. You want to maintain a healthy population of the beneficial microorganisms that break down waste, and like most living things, they require air and water to survive. Too much or too little of either can cause problems. Here are six simple steps to follow:
1. Choose the right site. You want a location that is convenient for your chores, so that you don't have to haul your stall and paddock wastes too far. But it will also need to be on high ground, on well-drained soil far from waterways. If your pile is at the bottom of a hill or in a chronically wet area, it may turn into stinky, slimy mush.
A dry, level approach is important if you will need to drive up to the pile in your tractor or truck. To forestall potential complaints from neighbors, keep the compost well away from your property line. Check with local regulations to avoid any zoning issues. Some counties require building permits for any structure placed on a concrete pad.
2. Decide on the number of bins or piles. You need at least two, and maybe a third. You will start by piling your daily wastes into one bin. Once that's filled to at least three feet, leave it alone to "cook" while you start filling the second bin. By the time the second bin is filled, the first one ought to be fully composted. With a third bin, you could start filling the new space while you continue to store the finished compost in the first bin, to remove and use at your leisure. Some people may go as far as having four or five piles.
3. Keep it covered. Covering your compost prevents valuable nutrients from being washed away with the rain. You'll also prevent your pile from getting too wet in the winter or too dry in the summer. You can accomplish this in several ways, such as building a roof or a trapdoor over the top of the bin that can be opened up, or you can cover your bin or open pile with a tarp or heavy plastic sheet. Keep in mind, you'll need to pull back the covering every day when you bring in fresh manure, so you want a method that is easy and efficient to use. You might want to attach your tarp to one side of the bin so you can just toss it back; if you live in a windy area, you'll need to weigh your tarp down with stones or milk jugs filled with gravel.
4. Get air into the pile. On its own, air will permeate one to two feet into the pile, so it's important to get oxygen into the center as well. Turning the compost---rearranging the pile to fold the outer layers into the center and pull the interior portion out---is the most effective way to aerate it. How often you turn the pile determines how quickly it will be finished---you can do it as often as every two weeks, but once every month or two will still get the job done.
Large operations do this chore with a tractor. On a small farm it could be done with a shovel if you enjoy a good workout, or you could use a small utility vehicle that has a front-end loader. A simpler alternative, however, is to insert a couple of five- or six-foot PVC pipes with holes drilled into them as "chimneys" into the center of the pile; you could also insert a couple of holes down through the pile with a tamping rod. If you choose that route, you will still need to turn the piles occasionally to allow the material on the outer edges to compost evenly.
5. Keep it damp. Your compost material needs to be about as moist as a wrung-out sponge---damp, but not dripping. If you squeeze a handful, you should be able to produce only a drop or two of water. If it's too dry, you may need to add water from your garden hose as you're turning the pile. You could also add water to the manure in your wheelbarrow before you dump it in. If your piles are too wet, make sure they are draining properly and are protected from rain. Compost piles can also be too wet if they have too high a proportion of nitrogen-rich "green" ingredients. To fix this, blend in more "brown" ingredients, such as fallen leaves, straw or wood ash.
6. Monitor the heat. This step is optional, but one of the most useful aspects of composting is the heat generated by the microbes. A properly balanced compost pile can reach 130 to 150 degrees Fahrenheit, and if you want to be sure to kill all the pests, weed seeds and pathogens, you need to maintain that temperature range for at least three to four days. Each time you turn the pile, it will take four to seven days for the heat to reach its peak again. You can easily monitor internal temperatures with a long-stemmed compost thermometer purchased at a local garden center.
WHEN IT'S READY
Finished compost has a rich, dark crumbly texture with a sweet, earthy smell. You should not be able to detect any trace of the original components. The temperature will have cooled to 90 degrees or less. How quickly yours reaches this state depends on how often you turned it and how actively you monitored the air and water. On average, you can expect it to take two to four months, but the time frame may be longer in the winter.
Compost will loosen and aerate clay soils or add organic texture and increase moisture retention in sandy soils. Work it into your garden and flowerbeds to improve the health of your plants, and lay it around trees and shrubs as a mulch.
You can also spread it on your lawn and pastures. The ideal time to spread compost is during the growing season, from late spring to early fall. You can use a manure spreader or simply use a shovel from the back of a pickup truck. To avoid smothering plants, sprinkle only about a quarter- to a half-inch at a time, and no more than three to four inches per season in the same area. No need to keep horses away from newly spread compost---if it has been properly prepared, any dangerous parasites or pathogens will be long gone.
If you own a farm, manure happens. But with a little planning and a moderate amount of effort, you can make compost happen instead.