Composted Horse Manure and Stall Bedding Pilot Project

Why Study Compost as Bedding for Horses?

The purpose of this project was to study and promote the use of compost as an alternative horse stall bedding and encourage horse owners and managers to think more creatively about manure management. Our objective was to reduce bedding use, and improve manure management practices at equine facilities in Snohomish County, Washington State.

Recreational and professional horse owners contribute to maintaining agricultural open space and supporting the agricultural infrastructure and local economy. Horse owners have historically been overlooked as contributors to animal agriculture, and as a result many horse owners lack a basic knowledge about manure and nutrient management. They are not aware of their impact on water and soil quality. Disposal of used stall bedding is costly for horse owners in northwestern Washington State, and has a potentially large impact on water quality. Disposal practices often include filling in low spots and ravines, or building massive piles. Composting manure at high temperatures eliminates pathogens and parasites, stabilizes nutrients, and reduces odors and vector attraction.

What did we do?

The Snohomish Conservation District (SCD) worked with ten commercial and two private equine facilities to test the use of compost as an alternative horse stall bedding material. Facilities ranged in size from 5 to >20 stalls. The primary system used for composting and reusing bedding involved a micro-bin composter (O2 Compost, Snohomish, WA) and a Stall Sh*fter® (Brockwood Farm, Nashville, IN). Micro-bins were assembled on-site and filled with used stall bedding (Fig.1-2).

Figure 1. Assemble compost micro-bin on site and fill with manure and beddingFigure 2. Turn on blower to provide aeration and monitor temperature

After 30 days of composting, the bin was emptied and the manure was separated from the bedding (Fig. 3). The composted bedding was then used in a stall (Fig. 4). Equine facility managers provided feedback on the effectiveness, perception, and impacts of using the compost as stall bedding. Results varied between trial sites based on type and quantity of bedding used, season, and stall management practices.

Figure 3. After 30 days of composting, empty the bin and sort the composted manure from the bedding using the Stall Sh*fter (registered trademark)

Figure 4. Use composted bedding in the stall and composted manure in the garden.

What have we learned?

Composted stall waste makes a soft absorbent bedding for horses or other livestock. Composted bedding is less dusty than shavings or wood pellets, darker in color, and has a pleasant earthy odor. There were no reports of composted bedding increasing stall odors or flies, or negatively impacting horse health. The best results were reported when mixing the composted bedding with un-composted bedding in equal proportions or two parts compost to one part bedding. There were some reports of horses with skin and respiratory conditions improving during the time they were on composted bedding, including thrush in the feet, hives and “rain rot” on the body, and “scratches” on the legs.

When separating the composted manure from the bedding, the amount and type of bedding determines the effectiveness of a bedding re-use system. Concern about appearances was more prevalent than concern about disease or parasite transfer. Even though barn managers were not entirely ready to make the switch to composted bedding, this project helped start many conversations (in person, through publications, and social media) about manure management and resource conservation. It was a great opportunity to help horse owners make the mental leap from “waste” to “resource”.

Future Plans

This project demonstrated that compost is a safe and effective horse stall bedding. Future work should be focused in three areas:

1. Developing systems for making composted bedding that are practical on a large scale and provide an economic incentive for large equine facilities to recycle their waste.

2. Outreach and education programs directed at horse owners who board their animals at commercial facilities. Would some horse owners be willing to pay a premium to board their horses at a facility that is managed in an environmentally sustainable manner?

3. Clinical trials to examine the effects of composted bedding on skin and respiratory conditions.


Caitlin Price Youngquist, Agriculture Extension Educator, University of Wyoming Extension

Additional information

Visit, a project of the Snohomish Conservation District.

The full report, including photographs of trial sites, is available on the Western SARE website:


I would like to thank all of the farm owners and managers who very graciously participated in this project and were willing to try something new. The contribution of time and energy is very much appreciated.

Thanks also to the staff at O2 Compost for their efforts, ideas, and creativity. This would not have been possible without them.

And Mollie Bogardus for helping take this project to the next level, and explore all the possibilities.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Extension Recognizes Pennsylvania Farms that Adopt Sound Management Practices Protecting Water Quality and the Environment

penn state extension environmental friendly farm signPurpose

The Environmentally Friendly Farm program was developed by Penn State Equine Extension and is designed to recognize farms that adopt environmentally sound management practices that protect water quality and the environment. The program is supported by funds from the USDA Natural Resource Conservation Service (NRCS), Conservation Innovation Grant. Strategies are employed on Environmentally Friendly Farms to maintain productive pastures, reduce soil erosion, limit nutrient runoff from animal facilities and barnyards, safely store manure, recycle nutrients, and control animal access to surface waters. Excess sediment and nutrient runoff from manure poses health threats not only to the environment, but also to animals and people. Farm managers who practice environmental stewardship maintain healthy environments for their animals, their families, and their community.

What did we do?

Farm managers can apply for the program by request a copy of the application from Penn State Equine Extension by visiting us online at, emailing or calling our extension office. Second, complete the Environmentally Friendly Farm application requesting background information about the farm operation.

Next, complete the Environmentally Friendly Farm Self-Assessment Checklist. Each statement is checked “yes” if the practice is in place on the farm, “no” if the practice is not in place or “non-applicable if the statement does not pertain to the farm operation. The checklist consists of a series of statements that identify potential on-farm practices in the following areas: Environmentally Sensitive Areas, Pastures, Animal Concentration Areas, Manure Storage, and Mechanical Manure Application.

Once the paperwork has been received, a farm site visit will be scheduled. Personnel from Penn State Extension, the County Conservation District, or the Natural Resource Conservation District (NRCS) will visit farms to verify that statements made in the application and checklists are accurate. At the same time, additional information and assistance will be provided to help improve farm management and develop any necessary plans for the farm.

The farm will be recognized by the public, conservation and agricultural agencies, and other farm managers as an operation that is committed to clean water and a healthy environment. Each farm manager will receive an Environmentally Friendly Farm sign that can be displayed on the farmstead. Farms that qualify will also be given permission to use the Environmentally Friendly Farm artwork on their website, brochure, and other marketing materials. Approved farms will be listed on the Penn State Equine Extension website.

This recognition will reflect the commitment of the farm manager to environmental stewardship and can serve as a marketing tool for the farm.

What have we learned?

After personnel visited farms to verify that statements made in the application and checklists are accurate. At the same time, additional information and assistance is provided to help improve farm management and develop any necessary plans for the farm. In addition, agency personal developed a personal relationship with the farm manager. The farm managers who practice environmental stewardship maintain healthy environments for their animals, their families, and their community.

Future Plans

This program will be continued through 2016. We hope to provide additional information and assistance to help improve farm management.


Ann Swinker, Extension Horse Specialist

Donna Foulk, Helene McKernan, Pennsylvania State University, University Park, PA 16802

Additional information

Farms can request a copy of the application from the Penn State Extension Equine Team by visiting us online at


This program was funded partly by a USDA NRCS-CIG grant.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Low Cost Aerated Static Composting Systems for Small Acreage Equine Operations

Why Study Low-Cost Composting?

The equine industry in Massachusetts, estimated to be over 50,000 animals, is of a size to make significant impact on non-point source pollution. An average horse generates about 45 lb. of manure per day, almost 10 tons per year as well as bedding. Thus, in Massachusetts approximately 500,000 tons of manure plus associated stall bedding are produced each year. Management of manure and mud on horse farms is a challenge for horse owners and equine facility managers. This is of particular concern at farms where horses are kept in stalls and land availability for manure spreading is limited. The growing number and size of unmanaged piles of manure seen on many properties is becoming an increasing concern due to greater public awareness and pressures in an increasingly urban society. Runoff from stables, manure piles and over grazed pastures has the potential to increase risks of non-point source pollution from nutrients, organic particles, fecal coliform bacteria, and other pathogens. Related: Small Farm Stewardship

What did we do?

aerated trash bins system

Figure 1: Aerated trash bins system

Perforated wood to be installed at the bottom of the bins for air flow

Figure 2: Perforated wood to be installed at the bottom of the bins for air flow

Composting pile with cover

Figure 3: Composting pile with cover

automated air blower connected to perforated PVC pipe

Figure 4: Automated air blower connected to perforated PVC pipe

Through a 319s grant funded by Massachusetts Department of Environment Protection, two Aerated Static Pile (ASP) composting systems, also known as forced aeration were installed to manage livestock manure and bedding produced on Blue Star Equiculture Farm in Palmer, Massachusetts. A community-based 501c3 non-profit organization, Blue Star Equiculture was established to provide retired and homeless working horses a sanctuary and the opportunity to improve their lives and be purposeful. The organization also offers equine and environmental awareness to the public through educational and healing opportunities.

Blue Star Equiculture currently manages their manure by hauling it to a nearby field. The Blue Star Equiculture has 30-40 horses at any time and expects an increase in number of animals. Considering an average of 45 lbs/day of raw manure, 35 horses generate a yearly mass of 575,000 lbs (287 tons) of raw manure that affects the Lower Ware River and Chicopee main stem. The current loading of nutrients by the Blue Star Equiculture herd is roughly 4000 lbs/year of nitrogen and 1200 lbs/year of phosphorus. This has implication on macrophyte growth and eutrophication of the Chicopee River.

The 30 herd horses in Blue Star Equiculture can contribute to 4.6 x 10¹² organisms/year of fecal coliform, and can lead to water quality impairment in the Chicopee and Connecticut rivers. The first system consisted of three plastic trash bins, each holding roughly 750 pounds of waste (Figures 1 and 2). The bins are connected to an air compressor/air blower which automatically turns on for roughly one minute every hour. The exact duration and frequency of the aeration varies and is controlled by a low cost credit card sized microcomputer with temperature sensors. It is calculated based on ambient and manure temperature and the composting phase. The automated adaptability increases the composting success and sustains the processes into the colder seasons. Furthermore an optional WIFI internet connection provides remote process monitoring and alerting. Finished compost is ready in 7-8 weeks including curing time. A layer of finished compost added to the top of the waste facilitates the process.

The wheels under the bins make collection of waste in the stall much easier. This simple and cost efficient system is especially applicable in facilities with 1-3 horses.

The second system consisted of one or more composting piles about 35 ft long (Figure 3). Each pile can be subdivided into three 10 ft section for frequent addition of fresh materials and/or removing finished compost. The composting materials are piled on a wood chip base with perforated PVC pipe running through the base and a 1 HP air pump which works for 1-2 minutes every hour. The pile is covered with a fabric which is impermeable to water. The compost in each subdivision is finished in 8-10 weeks including curing and finishing time. The same blower control and manure sensory system used for the bins was also utilized with the large pile setup.

What have we learned?

Both composting systems worked efficiently and compost was ready in eight weeks. Composting of horse waste at the Blue Star Equiculture significantly reduced pollution related to nutrients and pathogens. Aerated composting systems were used for hands on training workshops where over 400 horse owners learned about these systems and some of them implemented on their farm.

Future Plans

Similar system will be installed at University of Massachusetts Horse Farm to educate students of equine management as well as hundreds of visitors coming to the farm annually.


Masoud Hashemi, Extension Associate Professor, University of Massachusetts

Atakan Kadi

Additional information


This project has been financed partially with federal funds from the US Environmental Protection Agency (EPA) to the Massachusetts Department of Environmental Protection (the Department) under a s319 Competitive Grant. The contents do not necessarily reflect the views and policies of the EPA or of the Deparment, nor does the mention of trade names or commercial products constitute endorsement or recommendation for use.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Benefits of Bedding Reuse for the Equine Industry

Waste to Worth: Spreading science and solutions logoWaste to Worth home | More proceedings….

Why Studying Bedding Reuse for Horses?

To examine the financial, operational and health benefits of re-using composted bedding in the equine industry.

What Did We Do?

Stable waste, consisting of manure, urine and wood shavings, is a readily compostable feedstock that generates heat and can be transformed into finished homogenous compost, which can be used as bedding for horses and other livestock.  This transformation can be completed in as little as 2 weeks with in-vessel technologies, 15-25 days in aerated site-built systems and 20-30 days in aerated static pile (ASP) systems.  If composting is done in a biologically active, aerobic environment such as the systems mentioned above, the process destroys weed seed, parasites and harmful pathogens. These benefits are the result of system controls such as a correct ratio of C:N, moisture, porosity of the pile, and temperature.  The in-vessel composting system offers the most comprehensive control of these factors ensuring the most favorable results. 

The biological process that occurs when the stable waste is blended utilizes the leachable N and binds it in the organic matrix keeping it secured.  There is also a reduction in N during the process as it becomes volatile and escapes through vaporization.  The phosphorus is utilized by the bacteria during the process, reducing the amount available to leach by at least 50%.   Since both N and Ph are needed for cellular growth, they get locked in the cells of the growing bacteria.  This process generates heat, removing the moisture, killing pathogens and creating drier and more absorbent material for bedding re-use.

IOS Ranch, a private 20 horse show stable on Bainbridge Island, Washington, was the study site for this paper.  They purchased an Earth Flow in vessel system and it is from this system that the lab results and observational data were collected.  Their bedding of choice is medium sized bulk shavings.  Also studied over the same period of time was the Earth Flow in-vessel system at Joint Base Myers/Henderson in Arlington, Virginia.  The US Army Caisson horses stabled there are bedded on pelletized bedding.  Lab data from this composting mix contributed to this study as well.

Washington State University, encouraged by the potential of financial savings, started using composted material as bedding in the school’s dairy farm.  An unexpected benefit of this decision was the reduction of mastitis in the dairy herd.  The change in bedding was the only variable altered in the care of the herd when this observation was noted.  A study conducted by Cornell University’s Waste Management Institute studied the financial effects of using manure solids (DMS) as bedding.  This study showed an average of $37,000 was saved annually by the diary farms who switched to re-use bedding.  It was from these observations that we decided to apply the same questions to the equine industry. 

A study conducted by Caitlin Price Youngquist of the Snohomish Conservation District, and funded by Western SARE is searching for the health benefits to horses with the use of composted stable waste as bedding. Preliminary examination has shown an increase in foot and leg health and a decrease in thrush, scratches and dermatitis seen on the horses in the study.  General foot and leg health was also attributed to compost bedding by Dr. Hannah Mueller of Cedarbrook Veterinary Clinic and Northwest Equine Stewardship Center.  She documented relief for a horse with chronic hives and a horse with a tracheotomy.   The reduction of dust has been cited as a benefit to the horses suffering from heaves and other dust related ailments such as skin and respiratory irritations.  The compost material has the  unique quality of a large capacity for absorption while at an already higher level of moisture that makes the compost bedding less dusty. Both pellets and shavings exhibit this attribute.Youngquist’s assumption for the benefit composted bedding offers is based in the process itself.  She states, “The compost has been through a very hot phase to kill all pathogens and parasites. It now has a thriving microbial population that competes aggressively with the fungal and bacterial pathogens that cause infections and irritations on skin and hooves (similar to the concept of a pro-biotic).”

Stable waste compost as bedding can be used in its entirety or screened to collect the larger remaining pieces of shavings for bedding, leaving the fines for soil amendment. Testing has shown in either case the composted material to have high absorbency, more so than green shavings.  When mixed with 50% new or green shavings, the stall is at its most efficient for health and comfort for the horse.  The composted material offers higher absorption, soaking up the urine off the stall floor.  With a top dressing of new shavings the stall is aesthetically pleasing to the human eye, light in color and offering the horse a barrier to the wetter, compost material below.  The compost bedding is odor free when reintroduced to the stall.   The introduction of at least 50% new shavings also supports the ongoing composting system, refilling the system when it has its 40-50% reduction of volume and the eventual breakdown of the shaving pieces with multiple trips through the system.    Continuing research is being done to understand the effect of pelletized bedding used in the bedding re-use loop without the introduction of a larger substance to affect the integrity of the material as it continues to be re –used.

The first test done was to measure the absorption ability of the three types of bedding mixes.  Two inches of material was placed in a plastic container.  The first test done on 2” of green shavings, the second test done on 2” of a 50/50 mix of green shavings and compost, and the third test done on 2” of compost.  Each of the variations was weighed before the introduction of water.  One gallon of water was poured over the material and allowed to stand for 2 minutes.  The container was then drained of any standing water which was measured.  The container was again weighed in each case after the water had been drained.  This procedure allowed for the measurement of absorption by both the increase in weight and the volume of water not absorbed by the material.

The new shavings taken from a loose pile absorbed the least, the 50/50 mix the next higher amount and the compost bedding absorbed the most moisture.  This is impressive when one considers that the density of compost bedding is higher before the introduction of the test water.  The compost material is comprised of the same woody fiber as the shavings but the edges have softened and loosened, and it is possible that the breakdown of the resins, which can be hydro phobic, allows for additional absorption ability.

We also tested for the moisture content of each bedding type with a simple oven test.  The material was measured by a two cup measuring cup and poured into a glass baking dish.  The material was weighed before going into the oven, set at 200°.  The material was then weighed again to determine the moisture content after 12 hours.

These preliminary tests were performed to study initial benefits noted with bedding re-use.  These are not scientific studies and are only intended to show possible indications for the purpose of this paper and to encourage further study.  With composting and bedding re-use, barns close the waste stream loop and create a value added product.

What Have We Learned?

The viability of composted stable waste to be re-used as bedding is proven to provide financial benefits by saving  on the cost of material purchase and in the disposal of stable waste.  It provides  further savings in health care costs.

Laboratory Results for Composted Stable Waste

Laboratory Results for Composted Stable Waste

Laboratory Results for Composted Stable Waste

Future Plans

We will continue to support the Snohomish Conservation District study run by Caitlin Youngquist by supplying composted stable waste and collaboration. 

We plan to run our dust measurement during the summer months when we actually have dust in the Pacific Northwest. A furnace filter attached to the intake side of an 18” x 18” fan would be left on at ground level in a newly bedded stall for three minutes while the horse was hand walked around the stall.  This would be repeated for the three bedding variations.  The filter would be weighed before being attached to the fan and again after the three minute period.   

Study of pellets as bedding re-use material will be done, measuring the health benefits and the viability of the product over multiple uses.

A controlled trial on direct contact allergens will be conducted on the three bedding mixtures.

We will continue to educate the equine industry and encourage a broad scale adoption of this closed waste system.


Mollie Bogardus, MBA Sustainable Business, Equine Specialist, Green Mountain Technologies, Inc. and Michael Bryon Brown, President, Green Mountain Technologies, Inc.

Mollie Bogardus,, Michael Bryon Brown,

Additional Information

Bogardus, Mollie. “Equine Applications/Case Studies/ IOS  Ranch and Fort Myer/Henderson.” Green Mountain Technologies. Green Mountain Technolgies, Inc., n.d. Web. 15 Mar. 2013.

Cohen, Jamie. “Composted Horse Manure:  The Pros and Cons.” The Florida Horse Feb. 2013: 23. Print.

“Equine Applications.” Green Mountain Technologies- lab results. N.p., 12 Dec. 2012. Web. 1 Mar. 2013.

LeaMaster, Brad, James R.  Hollyer, and Jennifer L. Sullivan. “Composted Animal Manures: Precautions and Processing.”   Cooperative Extension Service,College of Tropical Agriculture and Human Resources, University of Hawai‘i. University of Hawaii at Manoa, n.d. Web. 6 Mar. 2013.

Price Youngquist, Caitlin. “Composted Horse Manure and Stall Bedding Pilot Project – YouTube.” YouTube. Snohomish Conservation District, 17 Jan. 2013. Web. 1 Mar. 2013.

Schwartz, Mary, Jean Bonhotal, and A. Edward Stachr. “Use of Dried Manure Solids as Bedding for Dairy Cows.” Cornell Waste Management Institute. Cornell University, n.d. Web. 1 Oct. 2012.>.

Wheeler, Eileen , and Jennifer Smith Zajaczkowski. “Horse Stable Manure Management.” Cornell Cooperative Extension, Orange County Equine, Saratoga County Equine. Penn State University, n.d. Web. 6 Mar. 2013.

Zaborski, Ed. “Composting to Reduce Weed Seeds and Plant Pathogens – eXtension.” eXtension – Objective. Research-based. Credible.. University of Illinois at Urbana Champaign, 22 Oct. 2012. Web. 2 Oct. 2012.….


This report could not have been done without the support of Philippe Le Dorze at IOS Ranch.  His interest and pursuit of knowledge pushed us to continue to search for improvements and greater knowledge.

The staff at Joint Base Myer/Henderson, Amy Fagan especially, were also willing participants in the pursuit of the perfect compost recipe.  Paul Brezovec at Concurrent Technologies Corp was a tremendous support to the project and continues to encourage the use of Earth Flow vessels for other bases.

A special thanks to Caitlin Price Youngquist for her ongoing dedication, collaboration and interest in the phenomena of bedding re-use.


The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

How long should horse manure age before applying it to my flower and vegetable gardens? How much should I apply?

Material that has decomposed adequately will be brown and crumbly. It will have a fresh, earthy smell. The pile will also no longer heat up when you turn or mix it. When you examine the pile and it has reached this point, it can be used in the garden. There are several factors that will affect how quickly the manure will reach this point and how much you can utilize around your garden.

1. Does it contain bedding? Manure that contains sawdust/wood chips will decompose slowly because of the high carbon content of the bedding. If your horse manure includes wood chips or sawdust, consider layering the material with grass clippings (a good nitrogen source) to speed the process. Manure alone or with straw will decompose readily on its own.

2. Management. Manure that is piled and left alone will decompose slowly. This can take three to four months if conditions are ideal. It can take a year or more if the starting material contains a wide carbon:nitrogen ratio (as is the case when manure contains wood chips). If you pile the material and aerate it by sticking in pipes (see the publication at the end of this answer) and/or turning the material often, you can reduce this time to as little as eight weeks. This aerated process is commonly called composting. It has a number of advantages over stockpiling manure and allowing it to decompose unmanaged:
– You can use the product sooner.
– The heat kills most weed seeds and pathogens (making it safer to apply to vegetables).
– The end product will be more consistent.

3. Application to the garden. If it is to serve as a mulch around the flowers, it can be applied from 1 to 3 inches thick. This will suppress weed seed growth and help conserve moisture around the flowers. Compost does contain nutrients for the plants, but they will release fairly slowly. Fertilize the flowers as you normally would early in the season. Later on, you can fertilize if it appears the plants need it.

If you apply manure compost to your vegetable garden (about one pound per square foot maximum), make sure it is applied at least 60 days before you harvest the crop. You will still probably need to apply fertilizer as you normally would, especially early in the season. If you continue to apply the manure compost over a number of years, you will be able to gradually decrease your fertilizer use.

Some additional reading on horse manure composting is at: Composting Horse Manure.

What’s the P Index?

The P Index is the Phosphorus Index, a risk assessment tool to quantify the potential for phosphorus runoff from a field. The P Index helps to target critical source areas of potential P loss for greater management attention. It includes source and transport factors. Source factors address how much P is available (for example, soil test P level and P fertilizer and manure application amounts). Transport factors evaluate the potential for runoff to occur (for example, soil erosion, distance and connectivity to water, soil slope, and soil texture). The P Index allows for relative comparisons of P runoff risk. When the P Index is high, recommendations are made either to apply manure on a P basis or not to apply manure at all. When the P Index is low, manure can be applied on a N basis. Also, if the P Index is high, the factors that are responsible for the higher risk of P loss are identified, and this information provides guidance for management practices to reduce the risk. For example, if the P Index is high because of high soil erosion, a recommendation to implement soil conservation best management practices (BMPs) may lower the risk and allow safe manure application.

For additional information:

To find your state’s P Index, do a web search for “phosphorus index” plus your state name.

Author: Jessica Davis, Colorado State University

How can I prevent leaching of nitrate into groundwater from manure applications?

Nitrate contamination of groundwater occurs when excess nitrate in the soil profile moves along with water that is moving down past the root zone of the crop. In most cases, it is not possible to keep water from moving past the roots, so the only other option for preventing nitrate leaching is to avoid having excess nitrate present in the root zone during times when leaching events are likely to occur. Determine the available nitrogen content of manure prior to application, and don’t apply more available nitrogen than the crop can use. Make the applications as close to the time the crop will use the nitrogen as possible.

Although only available nitrogen is subject to leaching, organic form nitrogen will become available as it mineralizes, at which time it too can leach if not utilized by the crop. The amount of nitrogen that will mineralize prior to and during the crop season should be taken into account when calculating manure application rates. If significant mineralization from previous applications is expected, plan to have a crop present to utilize it prior to leaching events.

How do you calibrate a manure spreader?

Calibrating a manure spreader is critical to ensure that the appropriate rate of manure nutrients is being applied to a field. For some livestock operations, this practice may be a required practice as part of their permit. Calibration will differ depending on the equipment and type of manure being applied.

If you know the capacity of the spreader, you need to determine the width of each pass and the distance it takes to empty the spreader to determine the rate of application. A measuring wheel is a useful tool and can often be borrowed from a local Cooperative Extension or Natural Resources Conservation Service (NRCS) office. After you have determined both of those measurements, use the charts in the publication linked below to determine application rate.

If the capacity of the manure spreader is unknown and solid manure is being spread, you can use a process that involves setting out plastic sheets or tarps of known size and driving the manure spreader over them and weighing the amount of manure that is collected on the sheets. A 22-square-foot tarp is a convenient size because the net weight of the manure on the sheet will be equal to the application rate in tons per acre. A step-by-step guide on making these calculations for other size tarps is available in the publication linked below.

For more, including specifics on calibrating solid, liquid, and irrigation manure equipment, visit Calibrating Manure Application Equipment.

Author: Jill Heemstra, University of Nebraska Extension Educator

Horse Manure Management

With proper planning, manure management can be beneficial to both the farm and the environment. This article provides information on environmental and health impacts of manure as well as proper manure storage and management.

J.G. Davis, A. M. Swinker, and Crystal Smith


Manure management is a vital part of modern day horse ownership. Many horses spend a significant portion of their day in stalls, accumulating large amounts of manure and stall waste. Horse owners generally have a limited amount of time to spend caring for their equine charges; thus, efficient manure removal and disposal is crucial. Additionally, horse facilities are often managed on relatively small acreage, limiting manure storage and application options.

The intent of this publication is to educate horse owners on the effective management of horse manure. Horse owners will first gain a thorough understanding of the quantity and characteristics of manure produced by horses. Finally, on-site options for handling, storing and treating manure will be discussed, keeping in mind sound facility management and environmental stewardship.

Managing horse manure can be a complex topic, and the principles presented here should be tailored to your specific situation. Please contact your local extension agent or natural resources conservation service field office for technical support.


Horse Manure Production and Characteristics

Person cleaning horse stall

Horses produce large amounts of manure. In fact, if the manure produced from one horse were allowed to pile up in a 12-foot-by-12-foot box stall for one year, it would accumulate to a height of 6 feet. On any given day, the average 1,000-pound horse will produce approximately 50 pounds of manure. This amounts to about 8.5 tons per year.

Manure is not the only material being removed when stalls are cleaned. Wet and soiled bedding material must also be removed and can equal almost twice the volume of the manure itself. The amount of bedding material removed will vary by type — shavings, sawdust, straw — but on average, totals between 8 and 15 pounds. Total stall waste produced averages between 60 and 70 pounds per day, which amounts to approximately 12 tons of stall waste per year.

When managed properly, horse manure can be a valuable resource. Manure is a source of nutrients for pasture production and can be utilized as part of a pasture management strategy to improve soil quality. The fertilizer value of the 8.5 tons of manure produced annually from a 1,000-pound horse can amount to 102 pounds of nitrogen (N), 43 pounds of phosphorous (P2O5) and 77 pounds of potash (K2O). Nutrient values for manure vary widely. The type and quantity of bedding material included also affects the overall fertilizer value. If a more accurate measure of nutrient content is needed, contact your local cooperative extension office for a list of laboratories that perform manure analysis.

Environmental and Health Impacts

Many horse owners do not have enough land or vegetative cover to properly apply large amounts of manure and nutrients. If not managed properly, manure can deposit excess nutrients into the environment via surface runoff or as a leachate, or water-contaminated with manure, from improper manure storage and land application. This can negatively impact water quality and subject landowners to investigation, and in some cases, legal action under an Agricultural Stewardship Act. For these reasons, horse operations are encouraged to use best management practices and develop a nutrient management plan. Nutrient management plans describe the farm’s manure production, soil fertility and recommended manure application and removal rates. For more information on designing a plan specific to your farm’s needs or identifying other conservation resources, contact your local cooperative extension office.

Internal parasites, insects, rodents and odors can be manure-related health concerns on horse farms. These issues can be minimized through carefully planned manure storage and handling. Internal parasites may be found in horse manure and can compromise the health and welfare of the horses stabled or grazing the land. Composting manure and properly timed land application can limit the risk of parasite exposure. Insects, especially flies, become a nuisance on farms where stockpiled manure serves as fly larvae habitat. Flies breed when spring temperatures rise above 65-degrees F. Flies deposit their eggs in the top few inches of moist manure, and these eggs can hatch in as little as seven days under optimal temperature and moisture conditions. Therefore, fewer flies will develop if you remove manure from the site or make it undesirable for fly breeding through processes such as composting within a maximum seven-day cycle. Naturally occurring fly predators can also be used to limit the fly population at the manure pile but are no replacement for sound management practices. Rodents can be a problem when manure is stockpiled for extended periods of time, providing them with a warm, safe environment. Additionally, nuisance odor from manure piles can result in strained relationships with neighbors. Composting or timely removal of manure piles will help keep odors to a minimum. Finally, keep in mind that large piles of manure are not aesthetically pleasing to your neighbors or those visiting your farm. Keeping the manure storage site screened with vegetation or fencing or by location will help to enhance the beauty of your farm.

Horse Manure Storage and Utilization

The average horse produces between 60 and 70 pounds of stall waste per day. Multiply this by several horses, and it is easy to see the importance of having methods in place to manage the manure produced on a daily basis. Letting manure pile up in stalls and paddock areas leads to a host of problems. It is not only unhealthy for your horse — inviting for pests and odors — and aesthetically unpleasing, but the sheer amount of manure produced will overwhelm you. Many handling and storage options exist, but it’s up to you to choose the method that best suits your horse operation.

Horse operations with available land may choose to apply stall waste to pastures as fertilizer. This should be done based on soil-test results and nutrient needs. A soil analysis is needed to determine the fertility needs of a pasture. Soil analysis is provided through your land-grant university’s soil testing laboratory for agricultural operations, which include horse farms, free of charge. Contact your local cooperative extension office for instructions on how to take a soil sample. There are also private laboratories that offer soil-testing services.

In many situations, manure can be picked directly from the stall, deposited into a manure spreader, applied to the pasture and harrowed into the soil. Barns not constructed with a management scheme allowing for stall access by a manure spreader require manure to be carted from the stall to the manure spreader some distance away. In this case, ramps or dropped spreader parking can be helpful to avoid lifting the heavy, cumbersome stall waste. Keep in mind that when spreading manure from stalls bedded with sawdust or shavings, the applied stall waste can stunt plant growth. Wood products contain carbon that soil microbes use for energy but not enough nitrogen to build proteins. The microbes draw nitrogen from the soil to make up for this deficit to such a degree that they can actually limit plant growth. To manage this nitrogen deficiency, nitrogen fertilizer can be applied. Or, to avoid the problem completely, manure can be composted before it is applied to the land.

When direct pasture application is not an option, manure storage facilities become a necessity. The storage facility should be convenient to the barn. A general rule of thumb is to plan for 180 days of long-term manure storage. This allows operations the flexibility to store manure when conditions are not ideal for manure application, as when fields are frozen or wet. This storage area should be accessible to the equipment that will ultimately remove the accumulated stall waste. Manure storage facilities should also be downwind and screened from nearby homes to avoid potential complaints about odors and aesthetics. The size, type and location of manure storage facilities will vary by horse operation based on the amount of manure produced, length of time the manure will be stored and available land area. Always be sure to contact your local authorities regarding zoning regulations and additional restrictions.

Minimum separation distances commonly recommended for composting and manure-handling activities. Source: On-Farm Composting Handbook, NRAES-54
Sensitive Area Minimum Seperation Distance (feet)
Property Line 50-100
Residence or place of business 200-500
Private well or other potable water source 100-200
Wetlands or surface water (streams, ponds, lakes) 100-200
Subsurface drainage pipe or drainage ditch discharging to a natural water source 25
Water Table (seasonal high) 2-5
Bedrock 2-5

Manure Storage Construction

Manure storage should be designed to limit the chance of leachate entering surface and groundwater resources. Ideally, storage piles should be placed on gravel, hardened clay or concrete pads that slope inward. The construction of manure storage sites will vary, based on individual situations and soil types. For instance, concrete pads may be necessary in areas with sandy soils where contaminants are more likely to reach groundwater. Storage piles should not be placed in low-lying or flood-prone areas, and care should be taken to direct water from higher elevations away from the site. The natural resources conservation service or local soil and water conservation district offices can provide individualized manure storage design specifications.



Composting horse manure is relatively simple but does involve more than simply piling the water. While many farms stockpile their manure, few truly compost. Composting is essentially managed decomposition. Managing the process can virtually eliminate odor, flies, weed seeds and internal parasites found in horse manure and create a valuable soil amendment for resale or for pasture application. To manage a compost pile, the following factors must be taken into consideration: carbon to nitrogen ratio, oxygen, moisture and temperature.

Compost Pile

The microorganisms found in compost are most active when their diet contains about 30 times more carbon than nitrogen, or a C:N ratio of 30:10. Horse manure’s C:N ratio is typically 40:1 due to the large amounts of bedding mixed with it but generally doesn’t require additional nitrogen provided it has enough moisture and oxygen.

Composting is an aerobic process, that is, it requires oxygen. If a compost pile doesn’t get enough oxygen, these anaerobic conditions can result in unpleasant odors, such as those normally associated with stockpiling manure, and slowed decomposition. There are several ways to provide oxygen to a compost pile. The most common way is to turn the pile. For large piles or windrows, turning is generally done using the bucket of a tractor or front-end loader. For smaller piles, a pitchfork will certainly get the job done; but for these operations, you may want to consider using an aerated, static-pile design, which doesn’t require turning.

Typical horse-stall waste tends to be dry and will need added moisture to create the ideal conditions for compost microbes. The moisture content should be about 50 percent, or roughly the consistency of a wrung-out sponge. If rainfall does not provide enough additional moisture, the pile may need to be watered periodically. On the other hand, too much water can also be detrimental, displacing oxygen inside the pile and causing anaerobic conditions. If environmental conditions such as rain or snow are providing too much water, the pile may need to be covered. Some compost-storage designs call for permanent roofs, but properly anchored plastic tarps can be just as effective.

Compost Trouble Shooting
Problem Possible Cause Remedy
Fresh manure, but pile won’t heat up. The pile is: 1) too dry,
2) too wet; and/or
3) Outside temp is too cold.
1) Add water evenly to pile.
2) Aerate and cover.
3) Wait for warmer temps and turn as needed.
Pile was hot, but now temps are falling. 1) Pile is settling.
2) Moisture is less than 50 percent.
1) Turn pile; and/or
2) Add water evenly to pile.
Pile is more than 160-degrees F and has gray ash-like mold. Pile is too dry. Add water evenly to pile.
Pile has gone through two or more heat cycles but still has some material that has not decomposed. Wood shavings decompose slowly. Ensure pile has proper moisture content, add water if needed.
Pile emits bad odor. Pile is too wet and has become anaerobic inside. Turn to aerate and increase water evaporation, apply cover to limit additional rainwater.

* Table does not include all scenarios, see resources/references for more in-depth publications on the subject.

One of the best ways to monitor your compost pile is by using a thermometer. Compost thermometers should have a probe at least 36 inches long and are available through many garden supply stores. The goal is to have sustained temperatures of 130- to 150-degrees F in the pile interior. This will optimize decomposition and also kill pathogens and weeds.

Compost-pile design and storage facilities will depend on the size of the operation and the equipment available. For a farm with two to six horses, small static piles, which use perforated PVC pipes to draw in air and don’t require turning, may be ideal. While not necessary, the use of multiple bins can allow separation of distinct batches. In this situation, horse manure should be piled approximately 5 to 8 feet high with a base that is two times the width and length of the height. For example, a 10-foot by 10-foot bin could accommodate a pile that is 5 feet high. PVC pipes should be placed after the pile is about 1 foot high so that the ends remain visible as more manure is added.




Aerated Static Pile with perforated PVC pipes Example of bins suitable for small farms - doors and roof are optional




For larger farms with access to bucket loaders, manure spreaders and/or specialized composting equipment, larger piles or windrows may be the most efficient design options. These piles may be slightly larger in height and width and considerably longer but will require periodic tuning.

Example of mixing / storage area with buckwall


Compost will decompose more efficiently if the mix is uniform. Starting with a uniform mix is even more important in the case of static piles, since they will not be turned during the decomposition process. Some farms utilize a temporary storage and mixing area to aid in this process.



Benefits of Composting

  • Creates valuable soil amendment
  • Stabilizes nitrogen into a slow release form
  • Avoids the problem of nitrogen immobilization
  • Reduces manure volume by 50 percent
  • Destroys weed seeds, fly larvae and internal parasites
  • Eliminates or reduces the cost of off-site disposal



With careful planning, proper manure management not only protects the environment and increases the efficiency and aesthetics of your farm, but might also save you money while enhancing your pastures. The following resources provide more information on composting and additional facility design specifications.

Field Guide to On-Farm Composting and the On-Farm Composting Handbook, available from the Natural Resource, Agriculture, and Engineering Service(NRAES) at

Horse Facilities Handbook, available from the MidWest Plan Service at

Check out your local university’s agronomy handbook containing information on soil production, soil sampling, nutrient management, utilization of organic waste and more.