Markets for Composted Agricultural Waste

Why Consider Composting Manure?

Enforcement of nutrient management regulation has forced Maryland farms and agricultural facilities to adopt new waste management practices. Few options exist that are financially sustainable. Regulatory agencies witnessed the unexpected consequence of closing small and mid-sized farms who could not afford to institute new waste management technologies. To counter that consequence, Maryland Department of Agriculture offered grants to subsidize the development of innovative technology and business practices. These new systems and business models had to offer both financial and environmental sustainability.

What Did We Do?

The first step in this project (supported by the Maryland Department of Agriculture, 2014) was to identify the biological make up and characteristics of the stable waste both before and after processing. We measured nutrient content and form (N, P, K), porosity, moisture absorption and C: N ratio. By understanding what the material consisted of pre-processing, we were able to determine what effects different controls during processing would have on the end product. As an example, when using stable waste for bedding re-use the material is run through the composting system as quickly as possible. A shorter composting period with auger mixing technology allowed the biological activity to breakdown the manure balls, support the transformation of the waste nutrients and yet protect the integrity of the shavings for second use. Related: Managing Manure on Horse Farms

Next, the local markets were studied:

    • Soil types and needs: compost to add porosity, water retention, nutrients to soil
    • Weather patterns and created needs: compost added for water retention, binding material to diminish run off
    • Population centers for urban market: compost for landscape needs, potting medium
    • Rural character for on farm market: compost for nutrient replacement, bedding re-use
    • Cost of operations on local farms: cost of bedding, cost of disposal, cost of landscape material, cost of synthetic or imported fertilizer
    • Wholesale market needs: compost for distribution centers (Scotts products), soil specialty companies, land reclamation sites, Department of Transportation needs, green house growers

Identifiable, viable market channels to move the processed stable waste were necessary components of a business model.  Uses for the processed waste were identified both on site and off site.

On site uses were identified as:

    • Land application: field enhancement
    • Bedding re-use
    • Landscape use
    • Improved footing arenas
    • Land reclamation
    • Pelletized for heat systems
Off site uses were identified as:

    • Soil amendment
    • Land reclamation
    • Potting Medium
    • Food Waste Bulking agent
    • Whole sale distribution centers
    • Soil Specialty companies

What Did We Learn?

Data was gathered and studied from equine facilities with existing composting operations to illustrate what the benefits and challenges can be. IOS Ranch on Bainbridge Island Washington is a sustainably designed 7.5 acre property that supports 20-25 stalled horses. The design concentrates the structures, indoor arena, stall, office and supporting buildings, so there could be surrounding pasture turn out and an outdoor arena. The facility was paying high waste disposal fees. Their decision to bring composting technology to the farm was an effort to eliminate disposal fees and diminish their bedding cost through bedding re-use. However, once the system was installed a local landscaper visited the site and saw value in the compost. The material is now sold for $30/yard wholesale and $45/yard retail to local landscapers and gardeners. With the price of shavings for bedding delivered at $7.50/yard the business decision to sell the compost was an obvious one. The property was formerly a gravel pit with large areas of exposed pit run. Once realizing the value of the compost for land application, the owner spread on the exposed areas greatly improving grass performance in the turnout fields. This farm was saving $100-$140/day producing compost because of the reduced disposal fees plus profits from marketing, allowing for a breakeven on investment in 3 years.

manure composting operation on horse farm manure composting operation on horse farm manure composting operation on horse farm

Joint Base Myer Henderson Hall hosted a pilot project for composting of food waste on remote contingency bases. On this base the Army’s Caisson horses are housed in a 50+ stall barn. After the pilot was completed the in vessel composting system will revert to the base for processing the stable waste. The base has the choice of bedding re-use or using the compost for landscape needs on base and/or in the adjacent Arlington National Cemetery. Outside contractors were supplying the base with compost at nearly $400,000 per year. The project could pay for itself in the first year. Thorough lab analysis showed the compost to be consistently of high quality, pathogen free, and weed seed free.

army base horse manure composting photos

Currently two sites in Maryland are being studied; one an equine rescue facility housing 50-80 horses, and the other a dairy with 240 head. The use of composted stable waste as a peat moss replacement will bring value to the equine and dairy farms and to the large, local greenhouse industry. Currently 80% of the peat moss used in Maryland is imported from Canada. The farms selected are large enough that they can produce enough material for bedding re-use (savings of nearly 20% of operating budget) and/or sell the material to wholesale buyers. The composting material from both sites show the favorable attributes of peat moss, porosity and moisture retention. Blending can alter the nutrient levels to what the market needs by using the more nutrient rich dairy waste. The collection of compost and blending can be done on on site or at an off site location in cooperation with other local farms, this may help meet larger volume needs of wholesale buyers.

horse manure composting operation in Maryland horse manure composting operation in Maryland horse manure composting operation in Maryland

Future Plans

The Maryland projects are both two years in duration with continual data gathering and recording. The next step is the location and operation of a collection yard for multiple local farms to send their processed stable waste. Such a yard allows for mixing to meet differing market needs and the creation of large quantities of homogenous product for local greenhouse growers.


Mollie Bogardus, owner, Aveterra and representative of Green Mountain Technologies, Inc.

Additional Information


Dr. Pat Millner, USDA Beltsville, Research Microbiologist is lead researcher and mentor on these projects in Maryland.

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