Manure Management Strategies for Horse Farms

Managing manure is an inevitable aspect of equine stable maintenance and requires careful consideration. A successful manure management program will depend on multiple factors including the number of horses at the location, the amount of available land, and the stable/facility layout. ^[1]

Proper manure management can significantly mitigate environmental pollution that can impact land and water. ^[1] It can also prevent nuisances like odor and flies, as well as help to keep your horses healthier. ^[2]

A comprehensive manure management system includes collection, storage (whether temporary or long-term), and disposal or utilization. Various options for managing manure include land disposal, stockpiling for future handling, removal from the farm or stable, and composting. ^[2]

Composting can also render horse manure a valuable resource as it provides a source of nutrients for plants. However, implementing this strategy for managing manure is more complex than storing it for spreading or having it hauled away. ^[2]

Importance of Manure Management on Horse Farms

Horses produce a substantial amount of manure every day, necessitating considerable effort from caretakers to maintain clean stalls and properly manage manure in pastures.

An average horse can generate 50 pounds of manure daily, which equates to approximately 20,000 pounds of manure per year. ^[2]

Effective manure management is essential for protecting the health of horses and their environment. Key reasons to develop a manure management plan include:

Preventing Spread of Parasites:

Equine manure may contain the eggs of internal parasites such as strongyles and roundworms. ^[3] Improper handling can lead to contamination of pastures, feed, or water, leading to infection in horses residing in the area. ^[3]

Minimizing Pests:

Manure piles serve as breeding grounds for various types of flies and rodents such as mice and rats. ^[4] Some of these pests also carry infectious diseases that can impact horses and their handlers.

Preserving Water Quality:

Poorly managed manure piles can release excess nutrients and contaminants onto land and into water sources, disrupt the ecological balance, and cause environmental damage. ^[5]

Manure is rich in nutrients including nitrogen, phosphorus, and carbon. ^[6] When present in surplus, these nutrients can contribute to groundwater or surface water contamination as leachate escapes from stored manure piles and seeps into adjacent water bodies.

Manure can also contribute to eutrophication, which refers to excessive proliferation of algae due to an overabundance of nutrients in water. ^[6] This scenario can also cause depletion of oxygen in the water column and adversely impact aquatic life and overall water quality. ^[7]

Following Regulations:

Federal, provincial/state, and local regulations govern manure management and water quality and must be complied with to protect the environment and avoid legal consequences. ^[8]

Improving Aesthetics:

Poorly managed manure piles negatively impact property appearance and in some cases neighbor relations due to their unsightly nature and unpleasant odor. Methane gas produced during decomposition adds to the environmental impact. ^[9]

Equine Manure Production

Manure is comprised of solid and liquid waste components. It typically consists of 60 percent solids and 40 percent urine. ^[4]

On average, one horse generates 0.5 ounces of feces and 0.3 fluid ounces of urine per pound of body weight each day. ^[4] For a 1,000-pound horse, this amounts to approximately 31 pounds of feces and 2.4 gallons of urine daily. ^[4]

In total, the raw waste produced by one horse is approximately 50 pounds per day. ^[4]

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Sites Requiring Manure Collection

When contemplating manure management at your facility, it’s essential to identify all locations where manure needs to be collected, including stalls, pastures, turnout areas and riding arenas.

Pastures

Manure is naturally distributed on pastures by animals. Depending on the pasture, manure may or may not be collected from it.

A common belief among horse owners is that spreading manure in thin layers on pastures reduces parasite numbers by drying out the eggs (desiccating). This may be the case in dry conditions and when the temperature is extremely hot or cold, but when conditions are moist, parasites eggs may not be destroyed. ^[4]

Research shows that spreading thin layers of raw manure on pastures may actually increase grazing horses’ exposure to parasites by dispersing parasites across a larger area. ^[4] For this reason, it is recommended to leave manure piles in clumps and remove them for disposal outside the pasture area. ^[4]

Stalls

Stalls should ideally be mucked out daily to ensure a clean and healthy environment for horses. Removing soiled bedding and manure daily helps prevent the buildup of ammonia to maintain good air quality in the barn. For horses that spend more time in their stalls, more frequent cleaning may be necessary to maintain optimal conditions.

Soiled bedding removed alongside manure during stall cleaning can amount to 8 to 15 pounds of waste per day. ^[4] The volume of bedding nearly twice that of the manure, although it can vary depending on materials used.

For a typical mature adult horse, the total amount of waste removed from a stall each day can weigh up to 60 to 70 pounds. ^[1] This results in an annual waste production of approximately 12 tons per stall, with 8.5 tons consisting of manure. ^[1]

To put this into perspective, the amount of stall waste produced from one horse each year could fill a 12-foot by 12-foot stall to a depth of approximately 6 feet. ^[4]

Turn Out/Exercise Paddocks and Shelters

Manure may be collected daily, bi-weekly, weekly, or less frequently, depending on the facility and the number of horses in each area.

Riding Arena

Manure is collected as needed to maintain facility cleanliness.

Manure Storage

Manure storage sites are necessary for horse farms when direct pasture application isn’t feasible. Storage sites should be conveniently located near the barn for ease of access and positioned to accommodate the equipment used for transporting and managing the manure.

A general guideline is to plan for enough capacity to accommodate 180 days of long-term manure storage. ^[4] This allows flexibility to delay manure application to fields during unfavorable conditions, such as when fields are wet or frozen.

To minimize horses’ exposure to parasites, manure should be kept out of paddocks and should be properly contained and stored away from grazing areas.

The size, type, and location of a manure storage site depend on factors such as the amount of manure generated at the equine facility, storage duration, and available land area. Adherence to local zoning regulations and restrictions may also influence what type of manure storage is appropriate for an equine facility. ^[1]

Manure storage facilities should be positioned downwind and screened from neighboring homes to mitigate potential complaints regarding odors and aesthetics. ^[1]

Manure storage facility construction must also comply with provincial/state and federal regulations. ^[1] Seek guidance from local authorities when planning a manure storage site.

Types of Manure Storage

Manure storage methods can range from uncomplicated piling strategies to large, roofed, solid-manure structures. Common types of storage include:

Dry Stack

The most widely used and practical approach for managing manure is the dry stacking method. ^[2] Key components of a dry stack facility include an impermeable floor and three surrounding walls designed to contain the manure. ^[2]

An ideal surface for storing manure via the dry stack strategy is a poured concrete floor. ^[2] This surface should be gently sloped to facilitate drainage toward a vegetated filter strip, which is a permanent, sustained region of cultivated or indigenous flora. ^[2][10]

The facility’s walls should have a minimum height of four feet. ^[2] They can be constructed using poured concrete, cinder blocks, or horizontal or vertical timbers. ^[2]

Walls provide structural support, streamline cleanout processes, and help retain heat for composting. The choice of wall material depends on factors such as functionality, durability, and cost. ^[11]

Ensuring the dry stack structure is anchored below the frost line is key to stability. ^[2] The overall cost of implementing such a facility is typically moderate.

Stock Piling

Stockpiling involves storing accumulated solid manure and used bedding in a convenient location. This manure storage strategy differs from dry stacking as it does not involve the use of an impermeable floor and three surrounding walls ^[2]

An appropriate spot for stockpiling should be established on compressed ground to prevent rainfall from leaching pollutants into the soil and groundwater from the pile. ^[2] Using gravel or stone dust on compacted ground can serve as an effective base.

The loading area for a manure stockpile should also be on firm ground to prevent rutting during wet periods such as rainfall or spring thaws. ^[2]

Stockpiling is a more cost-effective option for managing manure compared to other storage methods. ^[2] Stockpiles may be covered or uncovered depending on what type of surface lies beneath them. ^[2]

Utilizing a plastic tarp to cover the stockpile proves beneficial in minimizing odor and deterring flies. ^[2] Additionally, this covering mitigates leaching concerns by preventing rainwater from permeating the pile. ^[2]

It is crucial to choose an appropriate surface for the pile to prevent leaching of manure nutrients into the soil. Compacted, clay soils are preferable as bases because they prevent nutrient leaching, whereas sandy soils permit nutrients to pass through.

A slight slope of one to three percent is recommended to facilitate drainage. ^[4] A vegetated filter strip is beneficial for collecting any drainage from the pile at the site of drainage. ^[2]

As wastewater traverses the soil profile and descends the mild slope, waste materials are removed through biological activity and adsorption within the soil matrix. ^[4] The primary biological processes occur in the topsoil layer, where aerobic (oxygen-using) activity ensures odor-free treatment. ^[4]

It’s important to note that not all soils are equally suitable, with some allowing rapid infiltration for limited treatment, while others are less permeable and result in surface runoff. Frozen soil is not effective as a proper filter. ^[4]

A general guideline is to allocate approximately 10 square feet of vegetated filter per gallon of handled wastewater. ^[4] Ensuring an even flow is crucial, and a well-designed spreading device at the filter strip’s entrance helps minimize short-circuiting of wastewater through the area.

Composting

The practice of composting manure and bedding provides several advantages. Composting produces a crumbly material that closely resembles nutrient-rich topsoil.

This finished compost is highly sought after, particularly by gardeners and landscapers, making it a marketable product. Composting offers additional benefits including the elimination of pathogens, less odor, and a decrease in the overall volume of manure and bedding of up to 50 percent. ^[1]

Successful composting requires meticulous management to achieve the desired end product. The pile must be turned on a regular basis to ensure oxygen flow through the pile needed for microorganisms to survive. ^[12] Piles also need to maintain moisture in 40 to 65 percent of pore spaces to support composting. ^[12]

Monitoring temperature cycles within the compost piles is crucial. The pile’s core should reach 140 degrees Fahrenheit to effectively eliminate pathogens and yield a relatively stable compost. ^[4]

The transformation of manure compost into a finished product can take from 2 weeks to 6 months with proper mixing or aeration. ^[4] The cost of implementing this manure storage method varies depending on the complexity of the facility.

Equine facility owners should check with their local enforcement agency or planning department to confirm permit requirements for a compost operation. ^[13]

Adding Nitrogen to a Compost Pile

The more bedding in a manure pile being composted, the more likely additional nitrogen will be necessary to facilitate the process. ^[14]

Bedding materials such as shavings and sawdust contribute high amounts of carbon to the compost pile. An excessive amount of this mineral can disrupt the ideal carbon-to-nitrogen (C:N) ratio, resulting in a slower composting process. ^[14]

Commercial fertilizers such as urea, ammonium nitrate, or other high-nitrogen fertilizers can be incorporated into the pile to provide the necessary supplementary nitrogen. ^[14]

For optimal results, nitrogen should ideally be evenly distributed onto each wheelbarrow load of manure deposited onto the pile daily. Alternatively, nitrogen can be incorporated into the pile during the turning process to ensure a balanced carbon to nitrogen ratio for efficient composting. ^[14]

Drainage Considerations for Manure Storage

Effective drainage is a crucial requirement for any manure storage facility. In any scenario, a site-specific design is highly recommended. ^[4]

Surface drainage water and runoff from adjacent roofs must be channeled away from designated manure storage pile areas to maintain optimal conditions. ^[4] The site should be graded in a manner that redirects surface runoff.

Vegetated filter areas present a cost-effective solution for on-farm wastewater treatment, with variable costs that can approach those of a septic system. ^[4] Alternatively, leachate can be collected and diverted to a holding tank or treatment system. ^[4]

Larger manure storage facilities that contain significant amount of waste may need to collect leachate in a tank and disperse it onto a vegetated filter strip periodically or irrigate it onto pasture. ^[4] The wastewater may be directed through pipes so it can be evenly distributed over the vegetation filter strip. ^[4]

Using a settling tank before allowing wastewater to be dispersed onto a vegetation filter strip is necessary if manure solids are present. ^[4] Proper vegetation establishment is vital before utilization. ^[4]

Selecting a Location for Manure Storage

When choosing a location for a manure storage pile, keep the following tips in mind: ^[6]

• Place it on a flat, dry surface with minimal risk of runoff into surface waters, sinkholes, or roads.
• Keep it near barns and other areas where horses are kept and manure is generated.
• Ensure it’s not visible from public places or neighboring residences.
• Select an area with ample space for machinery to maneuver around the pile if necessary.
• Maintain a proper distance from nearby water resources.

It’s also important to avoid the following when selecting a manure storage site:

• Don’t position it near water bodies such as rivers, streams, lakes, wetlands, springs, or sinkholes.
• Don’t choose hilly terrain.
• Don’t select low-lying areas prone to water pooling.
• Don’t select areas where water accumulates after rain or in flood-prone zones.

Hauling Offsite

When manure storage availability is limited, an option is to hire a certified manure hauler to come and remove the waste. ^[4] Haulers may take the manure to a centralized composting facility or may spread the manure on farmland. ^[4]

It is important to remember that the manure will still need to be stored in between visits. The use of dumpsters may be a costly but viable option when there is inadequate land for spreading or composting is not an option. ^[4]

Dumpsters should be placed on an impervious surface such as concrete to allow for the collection of any liquids. ^[4] Storage containers should also be appropriately sized, allowing for weekly emptying during the fly-breeding season. ^[4]

It is advisable to position the dumpster in a convenient location, allowing for the easy dumping of barn waste and accessible emptying by trucks in all weather conditions.

Another option for farms is to consider marketing manure. Livestock or horse owners may sell or give their manure away (composted or non-composted) for off-farm use. ^[4]

Gardeners are frequently willing to take or even buy composted manures. Crop farmers may be willing to spread the manure on their land during certain times of the year.

Manure Disposal

Direct disposal of manure and stall waste is possible via field application provided one has access to ample land and essential equipment such as a manure spreader. ^[4]

Manure acts as a natural fertilizer, promoting soil health and plant growth. However, field application of stored manure requires careful management to minimize environmental risks. ^[4]

Guidelines for Spreading Manure

Keep the following guidelines in mind when spreading manure on pastures at your horse facility.

• Spread manure thinly: Apply only the necessary amount based on soil tests to enhance your land. ^[4]
• Spread manure during spring and summer: Avoid spreading manure during frozen or rainy conditions that may lead to runoff. During these times, stockpiling manure and stall waste may be necessary. ^[4]
• Don’t spread fresh manure on grazing pastures: Fresh manure may contain parasite eggs that can live for weeks or months. However, fresh manure can be spread on pastures being rested or those grazed by other species. ^[4]
• Avoid contaminating water sources: Don’t spread manure on floodplains, areas with seasonal water runoff, near wellheads, high-water table zones, or slopes adjacent to streams and ponds. ^[4]
• Assess waste content before spreading: If your fresh stall waste includes sawdust or wood shavings, apply nitrogen fertilizer. Microbes may deplete soil nitrogen and hinder plant growth while breaking down wood products. ^[14]
• Apply fertilizer to the manure before spreading: Alternatively, you can incorporate fertilizer into the soil after the manure has been applied. Composted manure does not require additional nitrogen supplementation before spreading. ^[14]

Taking Soil Samples

To determine how much land you need to spread the manure on, it is recommended to conduct soil testing and analyze the nutrient content of the manure. This ensures that manure application matches the nutrient requirements of the crop being grown, preventing over-fertilization. ^[15]

A soil test will provide insights into the physical, chemical, and biological properties of the soil, helping you determine any deficiencies that can be addressed by the application of mature as a fertilizer. ^[1][15][16]

Soil samples can be collected either independently following laboratory guidelines or by enlisting the services of an agricultural consultant. ^[1]

These samples can then be analyzed for various parameters, including pH levels, organic matter content, concentrations of nitrate-nitrogen, phosphorus, potassium, calcium, and magnesium, as well as the presence of micronutrients such as zinc, copper, iron, and manganese. ^[16]

Work with a local agricultural extension service to interpret the soil and manure analysis results. They can provide tailored recommendations on the appropriate manure application rate for your specific crop needs and soil conditions.

Summary

• Managing manure is an important part of running an equine facility. Effective management prevents environmental pollution, controls pests, and improves horse health.
• Manure must be collected and stored properly until it can be disposed of. Ensure manure is stored in a way that reduces leaching of nutrients into the environment and controls odors.
• Common types of manure storage include dry stacking, stockpiling and composting. Smaller facilities may need manure hauled off-site.
• Field application transforms manure into a valuable fertilizer, enriching soil for plant growth. Soil testing helps ensure manure application is matched to soil requirements.