Environmental Management on Equine Farms or the Good, the Bad, and the Ugly

Why Look at Environmental Practices of Horse Farms?

Equine farms are often small acreages that may not have ready access to technologies and information appropriate to their farms. Westendorf et al. (2010a) found that many equine farmers use extension services less than other sources of information, but they may use feed stores or neighbors for information (Table 1); Marriott et al. (2012) also found a limited understanding of available conservation resources among equine farmers. Best Management Practice (BMP) adoption on equine farms is the focus of this paper.

Related: Managing Manure on Horse Farms

Table 1. Manure management information sources on equine farms (Total Respondents – 442)

Another Horse Farmer Trade Magazines Cooperative Extension Other Feed Dealer Internet Other Retailer
221 183 229 116 97 89 26

Westendorf et al. (2010a,b)

What did we do?

Equine farms generally dry stack their waste; in a NJ survey (Westendorf, et al. 2010b) over 70% of farms indicate storing manure on farm, many of these sites may lack BMP’s appropriate for a storage (Table 2, 3). Eighty-three percent in this survey had manure storages located greater than 61m from water or wetlands, and 86% had storages located greater than 61m from neighbors; this might indicate their storage does not pose a significant water quality or nuisance risk. Fiorellino et al. (2010) found that even with low levels of BMP adoption, most equine farms had a reduced water quality risk. Over 50% of NJ farmers indicate that they compost manure, but it is my observation that few actually do; the definition of compost may vary from mature compost to rotting decomposition. Seventy-five percent of farms bed with wood shavings, 25% with straw and the remainder with a combination of wood chips, wood pellets, and paper.

Table 2.  Percentage of New Jersey equine survey farms implementing various management practices (%)

Spread manure on farm
Manure storage area
Compost horse manure
Off-farm manure disposal
Maintain and use dry lot areas
Credit manure as a fertilizer
Regular soil tests
Drag pastures regularly
Clean stalls daily
Manure storage <50 ft. from water
Manure storage >200 ft. from water
Manure storage <50gt. from neighbor
Manure storage >200 ft. from neighbor

Westendorf, et al. (2010b)


Table 3. Percentage of equine survey farms spreading or storing manure (%)

No. of horses Spread Manure (n = 442) Manure Storage (n = 434)
1 to 2 55.2 65.3
3 to 5 59.2 62.9
6 to 10 55.3 80.7
11 to 20 50.0 87.9
21 to 40 37.8 94.4
> 40 37.5 93.3

Westendorf, et al. (2010b)

Nearly 60% of horse farms dispose of some manure off the farm; for use as fertilizer, to a centralized composter, on-farm compost for sale, or to be given away are the prime means of disposal; unfortunately some is removed by dumpster. Fifty-four percent spread some manure on-farm, of these only 39% account for any fertilizer value. If we trust the survey, then probably only 20-25% of the farms have an understanding of the fertilizer value of manure; this survey did find a positive correlation between manure spreading and soil testing (P<.05), suggesting some understanding of soil fertility basics.

Fifty-three percent of farms had a sacrifice or exercise lot that provides horses an area for eating, drinking, shelter, and relaxing if needed. A sacrifice area can help to protect pasture and grazing areas. Many farms only have a turnout lot for both exercise and grazing; this can result in greater mud accumulation and other possible water quality concerns.

A feed management survey (Westendorf, et al. 2013) was sent to 500 NJ equine farmers (see Table 4). Forty-five percent received feeding and nutrition information from a feed store, 20% from a veterinarian, only 3% from a professional consultant and 2% from extension. Most farmers had no concept of feeding to reduce excretion of nutrients such as phosphorus. Monitoring intake, cleaning feed bunks and contaminated lots regularly, and disposing all waste feed in the manure storage are good recommendations for all producers. Please see the Williams et al. (2015) abstract in the poster session for more information about an on-farm feeding project.

Table 4. Description of how feeding decisions are made (%)

Balance diets on your own Veterinarian advice No plan at all Feed store advice Consulting nutritionist Extension advice
45 20.5 15 14.5 3 2

Westendorf, et al. 2013

What have we learned?

In summary: 1. Many horse farms dispose some or all manure off-site; 2. Between 50 and 75% spread manure on crop or grazing land; 3. Most have at least a designated location for manure storage; 4. Larger farms are more likely to store manure. 5. Many farms have a low non-point source (NPS) pollution risk, but little understanding of BMP’s; and 6. Pasture management BMP’s are seldom applied.

Future Plans

Outreach should focus on the implementation of low-cost management practices that equine farmers are likely to adopt.


Michael L. Westendorf, Extension Specialist in Animal Science, Rutgers, the State University of New Jersey westendorf@aesop.rutgers.edu


Fiorellino, N. M., J. M. McGrath, B. Momen, S. K. Kariuki, M. J. Calkins and A. O. Burk. 2014. Use of Best Management Practices and Pasture and Soil Quality on Maryland Horse Farms. J. Equine Vet. Sci. 34:257-264.

Marriot, J. M., A. Shober, P. Monaghan and C. Wiese. 2012. Equine Owner Knowledge and Implementations of Conservation Practices. J. of Extension. 50: Issue 5. https://archives.joe.org/joe/2012october/pdf/JOE_v50_5rb4.pdf

Westendorf, M. L., T. Joshua, S. J. Komar, C. Williams, and R. Govindasamy. 2010a. Effectiveness of Cooperative Extension Manure Management Programs. J. Equine Vet. Sci. 30:322-325.

Westendorf, M. L., T. Joshua, S. J. Komar, C. Williams, and R. Govindasamy. 2010b. Manure Management Practices on New Jersey Equine Farms. Prof. Anim. Sci. 26:123-129.

Westendorf, M. L., V. Puduri, C. Williams, T. Joshua, and R. Govindasamy. 2013. Dietary and Manure Management Practices on Equine Farms in Two New Jersey Watersheds. J. Equine Vet. Sci. 33:601-606.b


This work supported by the New Jersey State Equine Initiative, the Rutgers Equine Science Center, and the New Jersey State Department of Agriculture.

Special thanks to Troy Joshua, USDA-NASS, New Jersey for help in setting up some of the surveys.

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.

Nutrient Management on Small Farms

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Why Should Small Farms Be Concerned About Manure Management?

The USDA defines a small farm as any operation with gross sales less than $250,000 per year.  A small farm might have 50-100 dairy cows in the Midwest or Northeast, it could be a 30–ewe flock of pasture raised sheep, or a 100 head sow herd or 10 head of beef cows and calves on a retirement farm; or even a flock of laying hens in a residential area.  This definition includes both commercial and hobby farms. 

Many small farm owners do not realize the value of the manure produced on their farms.  Manure is often disposed offsite or stored indefinitely on the farm, if manure is spread on farm a nutrient management plan may or may not be in place.  Small farms have fewer animals and often several animal species on the same farm. There may be limited acreage and/or a lack of equipment for spreading manure. Financial resources may be lacking, but lower cost solutions for manure management may exist.  Small farmers may not be aware of potential critical areas on the farm (sensitive water bodies, erosion, neighbor concerns, manure storage), and they may not understand the idea of nutrient balance. 

The following principles may help small farmers who develop nutrient management programs:

  1. Appropriate manure storage should be located at least 100 feet from water bodies, wetlands, etc.;
  2. Animal access to water bodies, wetlands, etc. should be controlled;
  3. Manure should be applied according to a nutrient management plan that balances nutrient content in the manure with crop nutrient requirements and uptake and optimizes beneficial use of nutrients from manure and bedding; and
  4. Minimize odors from manure storage and application areas.  The Livestock Poultry Environmental Learning Center has a series of Small Farms fact sheets; http://www.extension.org/pages/8890/lpes-curriculum-small-farm-fact-sheet


Michael Westendorf, Rutgers, The State University of New Jersey westendorf@aesop.rutgers.edu

Additional Information

LPES Curriculum Small Farm Fact Sheets http://www.extension.org/pages/8890/lpes-curriculum-small-farm-fact-sheet.

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.

Fencing To Limit Horses Access to Riparian Areas

Why Limit Horse Access to Water Bodies?

Fencing along stream banks, lakes, and wetlands (riparian areas) is important in order to limit the access horses have to the waterways. When horses area allowed free access to riparian zones, they can deposit manure on the bank or directly in the water. Horse manure may cause elevated levels of nutrients and/or microbes in water. This will be of particular concern in water bodies that are classified as impaired.

Buffer Zone

The area between the horses and the water is called a buffer zone because it buffers the water from the effects of animals. The purpose is to collect any sediment from the pastures before it runs off into the waterway. The distance that should separate the animals from the water depends on several factors including, soil type, slope steepness, and condition of the pasture.

What Type of Fencing Should Be Used?

There are many types of fencing that can be used. Your choice will depend on the potential safety concerns for animals and people, cost of the materials, equipment needed to install the fencing and the maintenance requirements.

The Natural Resource Conservation Service has guidelines that can be used for determining how and where stream bank fences should be implemented. The NRCS Field Office Technical Guide provides technical information on stream bank fencing.


Additional Information on Horse Manure Management

Author: Michael Westendorf, Rutgers, The State University of New Jersey

Stall Waste Production and Management

livestock and poultry environmental learning center logo with cow, pig, and chicken sillhouettes over a map of the U.S. with three circling arrows

How Much Manure Will a Horse Produce?

A 1,000 pound horse will defecate approximately four to thirteen times each day and produce approximately nine tons of manure per year. The 1,000 pound horse will produce, on the average, 37 pounds of feces and 2.4 gallons of urine daily, which totals about 50 pounds of raw waste per day in feces and urine combined. A horse kept in a stall may require fifteen to twenty pounds of bedding per day. Bedding products include: wood by-product (shavings, chips, or pellets), straw, hay, or paper. Bedding must be provided in stalls with cement floors, kept reasonably clean, and changed periodically. Manure plus bedding will have a volume of between two and three cubic feet per day.

Soiled bedding can equal almost twice the volume of the manure, but will vary based on management practices. A stalled horse will require the removal of 60 to 70 pounds of waste per day. This results in between 12 and 13 tons of waste per stall per year with 9 tons being manure, 3.5 tons urine, and the remainder bedding. The density of horse manure is about 63 lb/cubic foot. Annual stall waste from one horse will fill a 12 foot x 12 foot stall about 6 feet deep. This leads to a steady stream of manure to handle.

Daily manure and waste production from a typical 1,000 lb. horse
Manure Daily 37 lbs feces 2.4 gallons urine 51 lbs manure
Stall Waste Daily 15-20 lbs bedding (1.6 cubic ft) 51 lbs manure (0.8 cubic ft) 60-70 lbs stall waste/day (2.4 cubic ft)

(Table adapted from Pennsylvania State University, 2000, Horse Stable Manure Management)

Choosing a Bedding Material

Although straw, wood shavings, and bulk and pelleted sawdust are the most popular bedding materials, other sources may also be used. Pine shavings or sawdust will result in less disposable material than straw, and cannot be disposed of with mushroom producers. Disposal with the mushroom industry is an option in some parts of the country if horse are bedded with straw. Wood shavings, sawdust, and straw are relatively absorbent. Many horse owners, particularly owners of racing or performance horses, prefer shavings over straw because they are less dusty and may result in less respiratory irritation. Shavings produced from black cherry and black walnut should not be used. Even very small amounts of black walnut in bedding products can cause laminitis and founder in horses.

Bedding should be absorbent, dust-free, easy to handle, comfortable to the horses, readily available, easily disposed of, unpalatable (i.e. the horse will not want to ingest it), and affordable. The more absorbent a bedding is, the less matieral will need to be used. All beddings should be stored in well-ventilated areas to remain as dry as possible prior to use. For more information, see the following factsheet: Horse Manure Bedding Use.

Additional Information on Horse Manure Management

Author: Michael Westendorf, Rutgers, The State University of New Jersey

Managing Manure on Horse Farms

Why Is It Important to Manage Horse Manure?

When managed properly, nutrients from manure should be seen as part of a larger cycle occurring on the farm. Nutrients enter the farm as feed or fertilizer, are excreted as manure, and are subsequently spread on the soil, taken up by plants, or transported off the farm as waste. Related: Horse Manure Composting: Facilities and Methods

The soil can store nutrients, provided the amount of manure applied to the soil is not excessive. When land has excess manure, more nutrients than crops can take up, these nutrients will build up in the soil and pose a hazard to ground or surface water. Excess nutrients can be carried by water through runoff or leaching to surface or ground water.

To minimize environmental risk, all horse farms should develop management plans that provide for proper storage, use, and disposal of horse manure.

What Is Nutrient Management?

The purpose of nutrient management is to implement practices that permit the efficient use of manure for crop production while preventing environmental damage that may be caused by nutrients. Nutrient management planning is a site specific exercise and, if the recommendations are followed, nutrient losses should be minimal. In general nutrient management considers how many nutrients are accumulating on a farm, their potential impacts on the environment, and how to best utilize them. Usually considered in nutrient management planning are:

  • goals of the farm as well as any constraints,
  • available farm resources (land, equipment, financial resources),
  • potential critical areas on the farm (sensitive water bodies, neighbors concerns, erosion, manure storage etc),
  • and nutrient balance (shown in the figure below).
Recycling Diagram

Importance of Nutrient Balance

Farm nutrient inputs consist of feed and fertilizer, but also animals, legume nitrogen, and bedding. Farms may export nutrients through outputs such as grain, animals, milk, meat, eggs, manure, and hay. Some nutrients are recycled on the farm, from feed to livestock to soil to plant and back to feed again. The optimal situation is for the farm to remain in balance between inputs and outputs without losses either as runoff to surface water or as leachate to groundwater. For more information, see Whole Farm Nutrient Balance.

Additional Articles On Horse Manure Management

The challenges of managing manure nutrients are different on a horse farms than on many larger farms. Horse farms often have fewer animals and sometimes several animal species on the same farm, but may have limited acreage for spreading manure. Some horse farms also face a challenge because they do not export nutrients from their system the way that many other farms do–by marketing outputs such as milk or selling animals that are produced.

The following articles are available on this website and include links to additional resources for each topic.

You may also want to see Nutrient Planning on Small Farms. It provides information about how to feed animals and manage their diets; calculate how much manure is produced. There is also information on basic soil science and soil fertility; and nutrient (manure) management – manure use on and off the farm and nutrient management planning.

Author: Michael Westendorf, Rutgers, The State University of New Jersey

Exercise or Sacrifice Lots for Horses

livestock and poultry environmental learning center logo with cow, pig, and chicken sillhouettes over a map of the U.S. with three circling arrowsA sacrifice or exercise area is your animal’s outdoor living space ( see Exercise Areas) . It is called a sacrifice area because you are giving up land that could be used as a pasture in order to protect the remaining pasture area, which is saved for rotational grazing, hay production, forage stockpiling, etc. Related: Horse Manure Management Overview

Sacrifice Areas Protect Pastures

A sacrifice area can be used to secure animals while stalls are cleaned in the barn or routine maintenance (dragging, clipping, etc.) is completed. The use of a sacrifice area could result in increased pasture productivity because it gives you a place to keep the horses when you need to keep them off the pasture. For example pastures cannot survive continuous grazing and trampling during non-growing seasons, winter and droughts. Other situations where they are useful are; when the ground is muddy, when there is frost on the grass, and anytime the grass needs rest like after grazing.

Locating a Sacrifice Area

Sacrifice areas should be located as far away from wetlands, surface water, and wells as possible. They should not be located in drainage flows, such as ditches, and preferably on a level area at the top of a hill. Sacrifice areas should be surrounded by a thick stand of grasses that can filter sediment and nutrients washed from the sacrifice area. A common way to do this would be to have the sacrifice area surrounded by pastures that may be used for rotational grazing. Manure should be collected from a sacrifice area for disposal. The sacrifice area should be located close enough to the manure storage area to improve the ease of collection.

Since these areas may not be vegetated, they are likely to become muddy in wet or inclement weather. Wood chips, sand, and/or gravel, or even concrete may be used to provide an improved foundation and keep the area small. Feeding, watering, and shelter areas that are in the sacrifice area should have appropriate foundations surrounding them to prevent erosion from hoof traffic.



cc2.5 MIke Westendorf, Rutgers

Sizing a Sacrifice Area

They should be only as big as absolutely necessary if vegetation cannot be maintained in the sacrifice area. Because of substantial wear and tear, these areas will be sparsely vegetated; grass cover may be nonexistent. Sacrifice areas should be large enough to provide exercise for the animals using the area. Horse Facilities Handbook, by Midwest Plan Services recommends that pens be at least 1,000 square feet per horse. Don’t forget that appropriate fencing, some sort of shelter from the elements and water are necessary for horses as well.

There are two strategies to sizing and maintaining sacrifice areas: either keep the area just large enough for the needs of the animals and accept the fact that the lot surface will be bare, or use a large sacrifice area that is large enough to maintain a vegetative cover. The latter is preferred for environmental reasons.

Regulatory Implications of Continuous Use of the Sacrifice Area

Confining animals for more than 45 days in the sacrifice lot can define the area as an animal feeding operation. If that area has a connection with surface water, such as a stream or ditch running through it, or if it discharges to a water body and is deemed to be a significant risk to surface water by the state regulatory authority, the operation may be required to control the runoff from the exercise lot and obtain permit coverage. Therefore, it is strongly urged that producers manage their exercise lots and sacrifice areas as seasonal or temporary use, primarily keep animals on pastures, and not locate them in environmentally sensitive locations so as not to impact surface waters.

More information on pasture and grazing management and regulations can be found at Livestock and Poultry Environmental Stewardship Curriculum under small farms and CAFO fact sheets:

More Information on Horse Manure Management

Author: Michael Westendorf, Department of Animal Sciences, Rutgers, The State University of New Jersey

Off-Farm Manure Disposal

When a farm has more manure than can be properly applied to acreage that they own or rent, other options need to be considered.

Hire a Certified Manure Hauler

Some producers may contract with a hauler to remove the manure. The hauler may take the manure to a centralized composting facility or spread the manure on farmland. In some states a manure hauler must be certified to haul manure off the farm and on to the highways. Be sure your hauler is certified to avoid potential legal liability if there is an accidental spill by the hauler.

Even if you contract with a hauler, manure will need to be stored in between visits. For information on selecting a site and building an appropriate structure, see Storing Manure on Small Farms : Options for Storage.


For small farms, dumpsters may be used to store manure until it is removed. Dumpsters are placed near the stable and are replaced with an empty dumpster when full. The dumpster should be placed on a concrete pad or other impervious surface that allows for the collection of any liquids that leach out. Although expensive, dumpsters may be a viable option when there is inadequate land for spreading and the circumstances do not lend to composting.

Marketing the Manure or Compost

Farmers may also sell or give their manure away, composted or noncomposted, for off-farm use. Gardeners are frequently willing to take (or even buy) composted horse manure. Crop farmers may be willing to let you spread manure on their land during certain times of year.

Photo courtesy Chris Henry, University of Nebraska

Additional Information

Author: Michael Westendorf, Department of Animal Sciences, Rutgers, The State University of New Jersey

Pasture Management on Horse Farms

Proper pasture management is important to holistic farm management. Grazing animals deposit manure on pastures and exercise areas. This manure ultimately will either be incorporated into the pasture soil or if the pasture is poorly vegetated it may be a runoff risk. So, the first principle of managing manure with grazing animals is to ensure productive pastures. Productive pastures will reduce the risks of manure runoff by providing ground cover that will prevent soil erosion. These pastures will also take up nutrients from manure and use them for crop growth. Less productive pastures will not do this. ( ABC’s of Pasture Grazing) ( Spanish Language Version)

What Makes a Pasture Productive?

What are some elements of productive pasture management? Proper soil health and fertility will ensure a good growth environment for pasture species, both forage and legume. Manure can help to improve and maintain soil fertility by providing needed nutrients, (N, P, and K) and organic matter. These nutrients will help promote growth of grasses and legumes while organic matter from manure will help to provide soil structure, protection against erosion and improve natural soil fertility. Choosing the appropriate grass and legume species will help optimize forage management and pasture growth. (see More Equine Pasture Management Materials)

Pasture rotation is also practiced in order to optimize plant growth and utilization by grazing vegetation at the proper heights and allowing for proper rest and regrowth. Activities such as brush hogging or clipping, dragging to break up manure clumps, fertilizing and over seeding are also necessary components of pasture forage management.

Lush, well-managed pastures such as the one above will take up more nutrients from manure, be more productive and permit a greater stocking density, and will present a lower risk of agricultural runoff polluting streams and water bodies. (Photo courtesy USDA NRCS)

Sacrifice Areas

Exercise or sacrifice areas are designated locations for feeding, watering, exercise and relaxation for times when pastures are not accessible due to lack of growth (winter or drought), flooding, etc. (see Exercise or Sacrifice Lots for Horses) Generally, these areas have little or no vegetation. It is important that manure not be spread in these areas. They are meant to be sacrificed for animal activities in order to protect the remaining pastures. Runoff from sacrifice areas should also be managed to reduce the risk of water pollution caused by sediment and nutrients from these areas.


Erosion is a problem for several reasons. First, nutrients attach to soil particles. When they wash away, the Phosphorus causes algae blooms in freshwater. When that algae dies, oxygen in the water adheres to it, producing a lack of oxygen in the water for fish and other aquatic life. The sediment from erosion also covers nesting habitat for aquatic life and reduces visibility for desirable sport fish like walleye. Lastly, the runoff can contain bacteria from the manure that can be harmful to people downstream.

Erosion problems on small farms are often different than large farms. On large farms, most erosion may be sheet or rill erosion running off large fields. On smaller farms, erosion may more often be a gully where animals cross a stream. Or it could be poorly vegetated pastures that provide poor ground cover during precipitation. Fencing, watering and feeding sites, presence or absence of field buffers, and stream crossings can all influence erosion on a small livestock farm.



This pasture management section provides information about proper pasture management in order to reduce water quality, manure runoff and soil erosion risks that may be associated with poor pastures. The following links provide more specific information:

More on Horse Manure Management

Author: Michael Westendorf, Rutgers, The State University of New Jersey

Spreading Manure on Horse Farms

Equipment For Handling and Applying Manure On Small Farms

A tractor and a manure spreader are needed to ensure proper field application of stored manure. Some small farms may be able to utilize small ground-drive spreaders that can be pulled behind an all-terrain vehicle or pickup instead of a tractor. Pull-type spreaders are traditionally used, although truck-mounted spreaders are sometimes used on larger farms.

Solid manure can be removed from storage using front-end loaders, scrapers, or other handling equipment. Small or limited-resource farms can get by with equipment as simple as a wheelbarrow and pitch fork. The size of the equipment influences the time required to load, haul, and spread manure. For more information see Nutrient Planning on Small Farms.

Environmental Considerations When Spreading Manure

Manure should not be spread where and when there is any risk for water pollution, such as near streams, ponds, wells or other waterbodies. Your local soil and water conservation district or Natural Resources Conservation Service office can also help identify if additional special protection areas exist on farmland and bordering properties.

Stored manure should be applied to the soil in a thin layer to speed drying and discourage fly breeding. Spreading incompletely composted manure on horse pastures should be avoided due to the risk of infecting pastures with internal parasites. Manure should be spread at agronomic rates (rates equal to or less than plants will use in a year). When stockpiled manure is spread on crop fields, the application may not meet the total needs of the crop. Each source of horse manure will vary, especially when different bedding sources are used. Typically, a ton of horse manure will contain eleven pounds of nitrogen, two pounds of phosphorous, and eight pounds of potassium. Average values are given in the table below and can help to determine the number of acres needed to properly apply the horse manure. Refer to your local Cooperative Extension office to get a list of laboratories that will do manure analysis.

Nutrient Content of Horse Manure
Manure Percent Solids Nitrogen – N Phosphorus – P2O5 Potassium – K2O
(tons/year) % (lb./year) (lb./year) (lb./year)
9.1 22.0 102 40 84

When Should Manure Be Land Applied?

Spring is the preferred time to apply manure. Forage or hay crops generally provide the greatest flexibility in planning land application operations. Cool season grasses can generally utilize manure nutrients from early spring to late fall, and application equipment generally does not adversely affect the crop regardless of its growth stage. However, spreading manure on wet soils should be discouraged as it leads to soil compaction and tearing of the top soil.

Manure Nutrient Availability

When spread, not all nutrients in manure are immediately available for plant use. The amount of nitrogen available is a function of the percentage of nitrogen in the manure, whether or not it is incorporated in the soil, and the rate of organic matter decomposition of the manure. Nitrogen availability (during the first growing season) will range from 35% of the total nitrogen when manure is spread on the soil surface to 60% when immediately incorporated into the soil. Availabilities of phosphorus from phosphate (P2O5) and potassium from potash (K2O) are commonly set at 80% and 90% of totals, respectively. For links to publications that include more detailed information and formulas for estimating nutrient availability from manure see Manure Nutrient Management Educational and Informational Resources.

Manure Containing Wood Shavings or Sawdust May Require Additional Management

Horse manure often has an additional consideration when it comes to nutrient availability. Sawdust or wood shavings are high-carbon materials that require a great deal of nitrogen to break down. This process can tie up available nitrogen, rendering it unavailable to plants or crops. A fact sheet on how to manage horse manure that contains wood shavings or sawdust is Horse Manure Management: The Nitrogen Enhancement System.

Too Much Manure?

In situations where land application is not an option or the farm has more manure than can be appropriately utilized, the producer will need to consider Off-Farm Manure Disposal options.

Additional Information

Author: Michael Westendorf, Department of Animal Sciences, Rutgers, The State University of New Jersey

Managing Dietary Phosphorus for Livestock and Poultry

Phytate Phosphorus

Phosphorus is required in the diet of animals, but if overfed or wasted, can contaminate the environment and water supplies. Cereal grains fed to livestock contain phytate-bound phosphorus. Phytate-bound phosphorous is digestible by ruminant animals such as cows, sheep, and goats, but it cannot be digested by single-stomached animals, such as pigs and chickens. Phytate consists of a carbon ring structure with balanced phosphate groups surrounding the ring. Since horses are a hind gut fermenter, they are able to process the phosphorus much like ruminant animals.

Since phytate-bound phosphorous is unavailable to pigs, chickens, and other single stomached animals, phosphorous from other sources is supplemented to meet the needs of the animal. The extra phytate-bound phosphorus will be unavailable and excreted in the manure.

Reducing the proportion of cereal grains in the diet will usually reduce the amount of phosphorus fed. However, for pigs and chickens, and there are few economic alternatives to cereal grains. Plant breeders are working to develop feed grains lower in phytate content and higher in available phosphorus.

Phytase in the Feed

An enzyme called phytase can be included with the diet. Phytase will break down phytate and release digestible phosphorus. Mixing phytase (commercially available) in the diet will reduce the phosphorus required in supplements.

Interactions Between Nutrients

Another factor affecting phosphorus availability is the presence of other nutrients in the diet. Overfeeding calcium can limit the availability of phosphorus. Calcium and other nutrients should be fed in balance so as not to disrupt the availability of phosphorus.

Calcium:Phosphorus Ratio for Horses

Horses are a bit unique; they require calcium and phosphorus to be in a specific ratio in the diet. Young growing horses, as well as lactating mares, should receive a Ca:P ratio of 2:1, while mature horses not reproducing can get by with a 1:1 ratio. Calcium should never be fed at a level lower than phosphorus because phosphorus will tend to interfere with calcium absorption into bone. Horses at maintenance require .17% phosphorus in the diet and .24% Ca. The highest levels of phosphorus are needed in reproducing mares (.34%). Typical horse diets approach 2 to 3 times the required level of phosphorus, which can be detrimental to the environment. This high phosphorus level is partially due to the estimated Ca:P ratio in alfalfa hay being 6:1. Many horse owners try to counteract this by adding more phosphorus to the diets. Many equine supplements already contain more phosphorus than is necessary. There are also phosphorus concerns for ruminant animals such as cows, sheep, goats, and etc.

Ruminants and Phosphorus

Ruminant animals have a phytate enzyme produced naturally within the rumen that breaks down phytate-bound phosphorus and makes it available to the animal. According to the National Research Council, a lactating dairy cow requires between .35 and .40% phosphorus in the diet. Previous dairy feeding practices included as high as .55% or .60% phosphorus in the diet. This would mean an excess of 25 to 30 pounds fed to a cow in a normal lactation. If you multiply this over a dairy herd with 100 cows, then nearly 3,000 pounds extra phosphorous would be fed over the course of a year. Some dairy farmers think that phosphorus is a mineral required for proper reproductive function. While phosphorous is indeed important for normal bodily functions and is important for reproduction just as all nutrients are important for reproduction, there is no special link between phosphorus and reproduction in a cow. Most dairy farmers have already reduced phosphorus in their diets to levels given by the National Research Council.