Proper manure handling, storage, composting and recycling protects drinking water quality, nearby wetlands ecosystems and maximizes soil, crop and human health. Livestock manure offers many benefits as a source of natural fertilizer including nitrogen, phosphorus and potassium (NPK) as well as many other important nutrients. While improving soil fertility, manure also builds soil organic matter and enhances soil’s ability to hold water and exchange gases.
Best Management Practices for Manure
Dr. W. Michael Sullivan, Department of Plant Sciences and Holly Burdett, Cooperative Extension, University of RI, trained farmers and agricultural advisors in safe manure handling and composting practices. Livestock Best Management Practices (BMPs) for storing, managing and recycling manure offer many benefits:
- Improve production and profitability
- Protect drinking water quality & health
- Protect livestock health and well-being
- Improve field crop health and yield
- Improve work environment and quality of life
- Improve property appearance
- Improve public relations; be a good neighbor
- Protect surrounding environment
- Enhance wildlife habitat
Proper manure storage, composting and recycling is critical. Storage areas should be covered and contained to prevent runoff or leaching into surface or ground waters. Manure should only be spread during the active growing season; just prior to planting annual crops or cover crops and soon after harvesting hay crops. This optimizes nutrient uptake by plants and soils while minimizing runoff or nutrient leaching.
Manure Storage & Composting Capacity
Storage and composting capacity should also include used bedding. For example, the average horse produces 25 cubic yards/year of manure and bedding.
These livestock averages help farmers estimate the manure volume generated.
Animal Type/Size Pounds Manure/day Tons Manure/Year
- Horse (1000 lbs.) ...................... 50 ......................... 9
- Beef Cow (1000 lbs.) ................ 63 ....................... 11.5
- Dairy Heifer (750 lbs.) ............... 65 ....................... 12
- Pig (finish at 220 lbs.) ................ 14 ......................... 2.5
- Sheep/lamb (finish at 125 lbs.) ..... 5 ......................... 0.9
- Layer Hen (4 lbs.) ...................... 0.25 ................... 91
When managed properly, composting yields a stable product free of pathogens and weed seeds. The result is a source of natural fertilizer that is highly desirable for on-farm recycling or for potential sale to neighboring farmers and gardeners.
Efficient composting systems minimize manure storage capacity and processing time. There are a variety of composting methods and systems available. Their cost and complexity will be dictated by farm conditions and goals.
Aerated Bay Compost Systems
An Aerated Bay Compost System is a fast, efficient composting system that saves labor and protects water quality. Forced aeration reduces odor, flies and processing time. Compost can be finished in 21 to 30 days with another 30 to 60 days of curing. The aeration equipment reduces time, labor and large equipment needs because no mechanical turning is required.
The Aerated Bay Compost System can work well at a typical small livestock farm in southern New England. A demonstration facility at URI’s Peckham Farm shares conditions with typical small acreage livestock farms:
- Close to neighbors
- Close to surface water or drinking water wells
- Limited equipment available
- Limited land available
- Manure with high bedding ratio (straw, sawdust and/or wood shavings) resulting in high C:N ratio
The Aerated Bay Compost System at URI was made of three bays 8’ by 8’ by 4’ high with ten cubic yard capacity in each bay. This farm generates 10 yards of manure and bedding every three weeks. An 8’ by 26’ poured concrete pad in front of the structure aids tractor access, loading and unloading and provides additional water quality protection. A roof over the bins minimizes excess moisture and leaching.
A blower forces air through perforated pipe under a slotted floor beneath the compost bays. Each bay has its own set of perforated pipes with separate controls. A timer regulates the frequency and duration of the blower’s operation. Gate valves control the amount of air delivered to each bay. Temperatures dictate the duration, frequency and amount of air delivered to each bay. The blower motor can be solar powered.
An Aerated Bay Compost System works best when these procedures are followed:
- Size the system for the farm’s current needs with consideration of expansion plans. In climate zones 6 to 7, you will need four months storage capacity. In warmer climates, systems can be smaller for three to four months capacity; in cooler climates, larger capacities will be needed.
- Set-up, operate and maintain the electric blower and cycle timer.
- Prepare each bay for raw materials – establish a porous base of material (gravel around perforated pipes) for even airflow.
- Fill each bay properly. Plan material mix and moisture content. Pre-mix and add other raw materials as needed to achieve proper C:N ratio. Wet layers when installing and top if needed for proper moisture levels.
- Monitor and record the temperature frequently in each bay with 36” thermometer. At first, daily monitoring will be needed to tweak they system for peak efficiency. Over time, monitoring can be done once or twice per week to ensure proper operation.
- Adjust blower cycle timer (frequency, duration) and gate valves (air volume) to each bay, based on temperatures.
- Clean bays and aeration pipes as needed. Absorb leachate beneath the slotted floor, with wood pellets, sawdust or shredded newspaper.
- Cure and store finished compost
- Test the finished compost before spreading or selling.
A demonstration system was installed at URI’s Peckham Farm in 2010, designed by O2Compost using their adapted Aerated Static Pile (ASP) compost technology for small farms. The project was funded through a Natural Resources Conservation Service (NRCS), Conservation Innovation Grant (CIG).
The O2Compost Training Program for URI included equipment components, system design, training manual, technical support, laboratory tests of finished compost and assistance with developing a marketing plan for around $4,000. Other costs include excavation, crushed stone, concrete, lumber, other construction materials and labor. System cost will vary, depending on the size, design and how much of the labor a farmer supplies and range from $10,000 to $30,000 or more. Other costs may include a solar power kit and deep cycle battery at about $4,200.
To read about URI’s demonstration aerated bay compost system at Peckham Farm, here. Additional fact sheets and worksheets in livestock manure management and water quality protection are available here.
Learn more about O2 Compost and Price-Moon Enterprises here, call (360) 568-8085 or write them at PO Box 1026, Snohomish, WA 98291.
A six-part workshop series called “Conservation – There’s a Plan for That: An Introduction to NRCS Conservation Plans & Practices” was funded through a partnership between URI and USDA NRCS. The training sessions focused on planning and adoption of conservation plans and practices improving farmer and landowner skills to engage in and benefit from the USDA NRCS Environmental Quality Incentives Program (EQIP). Participants included farmers, agricultural advisors, and students and were not required to be enrolled in any NRCS Programs. For more information on the workshop series, click here, email Holly Burdett, call (401) 874-2249 or write URI Cooperative Extension Water Quality Program, 1 Greenhouse Road, CIK Building, Kingston, RI 02881.
A similar story ran in the February 4, 2013 New England issue of Country Folks.