Source and Safely Compost Large-Animal Manure
By Jeff Meyer
Collect manure from local sources — such as farms, dairies, and even zoos — to transform this nutrient-rich material into compost your crops will love.
For folks who don’t farm or garden, a malodorous pile of manure is usually a fly-attracting eyesore to be avoided. But most farmers and gardeners won’t turn up their noses at such a deposit; where some might see rank waste, they instead see nutrient-rich material that can be composted and spread over pastures or plants to help them flourish.
According to the University of Massachusetts, Amherst, Extension, animals excrete about 70 to 80 percent of the nitrogen (N), 60 to 85 percent of the phosphorus (P), and 80 to 90 percent of the potassium (K) found in their feed. So manure can often replace fertilizer, as it slowly and steadily supplies the same nutrients while simultaneously improving soil health and structure — something most fertilizers don’t do.
If you keep livestock on your property, they may make sufficient manure for you to put into your compost pile. If not, though, you can glean the goods from some unusual places, if you’re willing to get creative and call operations that might have unused piles of animal droppings on hand.
How (and Why) to Get Creative with Sourcing
Call local organic dairies, horse stables, organic chicken farms, zoos, and animal sanctuaries; nine times out of 10, they’ll want their manure hauled away. And not just because of the stench — manure that’s not properly handled can contaminate nearby waterways, polluting aquatic ecosystems and inducing harmful algae blooms. So partnering for a manure pickup is good for the environment as well as the parties entering the arrangement.
If a stockpile of manure has been languishing outdoors and exposed to the elements, then a lot of its nutrients will have washed or baked away. So the fresher the load, the better. After you’ve landed on a potential source, ask the following questions about the animals and their manure.
Image by Nate Graham
- Which species excreted the manure? (Never use waste from pigs or pets, as their manures can contain pathogens and parasites that aren’t neutralized through composting.)
- What do you feed your animals?
- What type of housing and bedding do you provide for your animals?
- Do you give your animals antibiotics?
- Have your animals encountered or eaten any pasture or feed that was treated with herbicides?
- How has the manure been handled and stored?
At Johnny Appleseed, we used to receive truckloads of chicken manure, but in early 2021, I reached out to White Oak Conservation, a 17,000-acre wildlife conservation facility, to see what they do with all of their dung.
We and the White Oak team agreed that a manure-pickup arrangement would be mutually beneficial, so we partnered with a local company to transport most of the stockpiled manure to the Johnny Appleseed farm over the course of a week, and we’ve since been picking it up as it’s produced. We receive about 200 to 240 yards of animal manure per month, which gives us enough to make at least 20 new compost piles. We’re slowly transferring the full supply to our farm and intend to use exactly as much manure as the animals produce so none of it goes to waste.
The White Oak team appreciates the opportunity to put the waste to use in a way that benefits the environment and our farm, and we receive a substantial amount of rich material with a higher carbon-to-nitrogen ratio than the chicken manure we were using. According to a study published in 2019 in the Journal of Advanced Scientific Research, many exotic animals only partially digest their food, so their dung is full of partially decomposed plant material. It’s higher-volume and breaks down more slowly than chicken manure, so it’s better for runoff and less smelly.
We’re also proud to partner with an organization that gives animals more privacy and high-value diets, and we admire its efforts to reduce habitat destruction by conserving land.
How to Include Manure in Your Compost Setup
Image by Nate Graham
After you’ve acquired manure, you can destroy harmful bacteria and weed seeds and process the highly concentrated nutrients in fresh manure by creating a “hot compost” pile, which involves a high-temperature technique that requires the regular introduction of oxygen to increase beneficial microorganisms and create compost quickly. Here’s how we use the Berkeley method of hot composting:
- Create a heap that’s at least 3 feet long, 3 feet wide, and 5 feet tall. If you need to go bigger, you can extend the pile as a windrow; for example, the pile can be 16 feet long, 5 feet wide, and 5 feet tall. A pile more than 5 feet wide and tall will generally require machinery to be turned.
- Maintain a compost temperature between 130 and 150 degrees Fahrenheit.
- Maintain a carbon-to-nitrogen ratio of 25-to-1 to 30-to-1. To increase the carbon content, mix brown leaves, straw, hay, dried grass, shredded paper, chipped tree branches, or sawdust in alternating layers with the raw manure. The uric acid and nitrogen in urine can speed up the composting process, so it’s acceptable to mix a bit of urine into your manure (if it isn’t already mixed in).
- Maintain the moisture content between 50 and 60 percent. To test this, don gloves and squeeze a handful of compost, which should release a drop of water. Large piles will need to be covered for protection from drying in the sun or cooling in the rain.
After you’ve built the compost heap, leave it alone for four days, and then incorporate oxygen by turning it from the outside to the inside every two days for two weeks.
Nutrients in manure can vary based on the animals’ species, diet, housing, and bedding, as well as the method of manure collection and storage. Experiment to find the right amount of moisture or carbon needed to balance your compost pile, and consider sending a compost sample to a laboratory for nutrient analysis.
Manage Manure Safely
Careful sourcing and asking questions are essential for knowing if your manure might contain antibiotics or broadleaf herbicides, both of which can pass through animals’ digestive tracts. Although hot composting can reduce the concentration of antibiotics and decrease antibiotic activity to safer levels, according to the University of Nebraska Extension, it’s best to conduct a bioassay test for herbicides by growing susceptible plants, such as peas, beans, or tomatoes, in the composted manure and comparing them with control plants grown without compost. If your control plants flourish but you witness signs of herbicide damage in your compost-grown plants, such as cupped leaves or stunted growth, your compost could be contaminated.
Otherwise, nutrient runoff and leaching are the most significant environmental concerns to keep in mind. To prevent any excess nutrients from reaching local waterways, locate your pile away from water, or install a catchment to store and sink the nutrients on your land, such as a berm and swale combination. If you can, continuously move your pile to give the land underneath some time to breathe and use up remaining nutrients. You could cycle back to the same location after a few rotations; use your power of observation to prevent various compost areas from becoming stinky mud pits.
When it’s ready to use, your composted manure will be a dark brown substance that smells good — or at least better than it used to. Earthworms will start to move in when the pile’s not too hot to host them. You’ll then be ready to incorporate this newly transformed amendment into your garden beds or fields.
Donate Your Dung
Do you own livestock? If so, you might have more manure than you need, making you the ideal local candidate for excess excrement pickup. Consider making your livestock’s byproduct available to the public. You can advertise your surplus manure in classified listings in local publications or online, schedule pickup windows a few days per month, and even charge a small fee (depending on demand in your area). This setup is especially ideal if you have a small piece of equipment you could use to help load the manure. Make sure you locate your manure on an accessible part of your property, where patrons can pull up with a truck and easily load it and haul it away.
Jeff Meyer is the founder of Johnny Appleseed Organic, an eco-village and online store that provides farmers and gardeners with resources to fight climate change.
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