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Managing Manure & Mud   arrow

Manure – Renewable Resource

You have heard of water in the West as “white gold“, but in our country, acres of farm animals create “black gold”, or manure. The manure from just one horse is worth over $150, if you had to buy fertilizer to put on your pasture. But in the wrong place, this “black gold” becomes a pollutant as it washes off the soil and into the nearest stream or well. In the stream, or well, the nutrients and bacteria may cause algae blooms, kill fish, and pollute drinking water.

It may not seem like your residence, with its manure pile and muddy corral is a big deal in the big picture. But, there are a few thousand of your size operations in this area of Colorado, and it all adds up to a potential major issue, if you don’t follow good manure & mud management practices.

Fertilizer Content in Horse Manure:

4 LB N/ton

4 LB P2 O5/ton

14 LB K2 O/ton

Let’s use a horse as an example: An average 1,000-pound horse produces 9 tons of manure a year (50 pounds per day), containing valuable fertilizer elements (see table). Add to that an Additional cubic foot of bedding material and you get 730 cubic feet a year from one horse.

Colorado’s horse industry uses two principal feed management systems, according to a recent survey. The first system permits horses to graze full-time on pastures and the manure is not collected or treated. Pasture manure usually is broken up by harrow cultivation that promotes decomposition.

The second system confines animal feeding, and the horses are kept in stalls or runs. The horses may be housed in box stalls and provided a bedding source for urine absorption. Alternatively, horses are kept in corrals, or runs and some runs are attached to stalls. Manure is managed in one or more of the following ways: 1) manure is removed daily and composted; 2) manure is removed daily and stored in piles; and 3) daily land application.

Manure & Mud Management

Key Issues

  • Raw manure and mud provide a breeding ground for flies.
  • Accumulated mud and manure cause thrush, rain scald, and other diseases.
  • Dried manure produces molds and causes respiratory problems in horses and cattle.
  • Heavy manure applications over fertilize grasses. Animals that eat these grasses may suffer nitrate poisoning and grass tetany.


Here are some examples of poor mud and manure management:

  • Manure pile is uncovered and placed in a low area. Nutrients and bacteria can leach into the groundwater.
  • Animals trample stream banks, get stuck in the mud, and cause soil erosion.
  • Water tanks concentrate animal traffic and manure next to the stream.
  • Roof gutters leak water onto the ground. Water creates muddy areas, picks up pollutants, and flows into the stream.
  • Uphill drainage is diverted away from the animal yard and into the stream.


Mud can make chore time unpleasant, increase fly breeding areas, transmit diseases, create unsafe footing, and increase polluted runoff. Often the best protection against mud is prevention. Reduce the amount of rain that runs through your animal yard and you will reduce mud and polluted runoff. Tips to reduce runoff include:

Install roof gutters … Install roof gutters and downspouts to divert clean water from the animal yards

Protect downspouts… Protect downspouts from animal and equipment damage by using heavy polyvinyl chloride (PVC) pipe, a hot wire, or a permanent barrier. Empty downspouts into a stock watering tank, rain barrel dry well; tile line, road ditch, or creek.

Control runoff… Locate new animal yards at least 100 feet from wetlands, ditches, and streams. Curb concrete animal yards or use an earthen berm around animal yards that are close to wetlands, streams, or ditches. Divert animal yard runoff away from wetlands, ditches, and stream and into a vegetated area that can filter the flow. Divert clean water above animal yards to wetlands, ditches, and streams. Close open ditches with a buried pipe to carry water past animal yards. Tips to reduce mud and potential pollution include:

Fence animals… Fence animals away from wetlands, streams, or ditches. Rotate water tank areas to avoid mud and manure buildup.

Use sacrifice area… Move animals into a corral, run, or pen when pastures are wet in the winter or when grass is less than 3 inches high in the summer. These holding areas are called “sacrifice areas” because the grass is “sacrificed” to preserve cover in the pastures. Locate a new sacrifice area on high ground and at least 100 feed away from wells and open water. Maintain a 25-foot grass buffer around the sacrifice area to filter polluted runoff.

Install firm footing… Muddy areas are often found at barn entrances, lanes, gates, and loafing areas.

Design drainage… Slope the animal yard with a 4 to 6 percent grade and use a southern aspect for quick drying


Horse owners have a responsibility to manage the manure that is a byproduct of their industry. Develop a management plan for manure and soiled bedding. Use it on croplands, arena and trail surfaces, and landscaping. If you don’t plan to use the manure yourself, develop a marketing plan so others can make use of it.

Contract or donate compost to crop farmers, community landscapers, parks, or neighborhood gardeners. Offer a discount to boarders if they dispose of manure. The people who come to watch others ride is another potential market for manure or compost sales. Before you can market the product, it must be completely and properly composted and free of foreign material such as pop cans, wire, and syringes.

Make an arrangement or contract with a landscaper, nursery or crop farmer. Be prepared to handle your own byproduct. One option may be to deliver manure, at your cost, to a site where contracts do the composting. Predetermine the bedding types they prefer in their compost mix.

Collection of Manure


Horses housed in stalls and sheds require soft absorbent bedding, pine wood chips, and straw. Remove manure and soiled bedding on a regular basis and handle appropriately to prevent fly infestation and disease transmission.

Pastures… Manure management in pastures depends primarily on getting good distribution of manure across the pasture. To void manure concentration in isolated spots in a pasture, distribute grazing evenly. Rotational grazing is one of the best ways to achieve this goal. Pastures can be split, and the horses moved back and forth between both parts of the pasture, to distribute the manure more uniformly. Availability of several watering facilities and moving feeding facilities periodically will encourage better manure distribution.

Avoid grazing during rainy periods when soils are saturated, to avoid soil compaction and manure runoff. Restrict access to streams to avoid manure deposition in or near water bodies. This can be done by fencing or providing shade away from the streams. Refrain from excessive stocking rates that lead to overgrazing. Damaging the grass stand increases manure runoff potential from pastures.


Stockpiling manure is commonly stockpiled prior to use. Adequate storage area allows for greater flexibility in timing of manure use. Therefore, be sure you have a large enough storage area to accommodate the manure produced. Over time, the manure shrinks from decomposition and moisture loss. Proper site selection for the storage area is important, to safeguard against surface and ground water contamination. Place stockpiles at least 150 feet away from surface water (creeks and ponds) and wells.

Establish and maintain grass buffer strips between water bodies and manure piles. Construct a perimeter ditch or beam around the storage area, if needed, to prevent runoff onto or off of the area.

Compost PileComposting produces a relatively dry end-product that is easily handled and reduces the volume of the manure. Composting at proper temperature can kill fly eggs and larvae, pathogens and weed seeds. Compost has less of an odor compared to raw manure and is more easily marketed. Composted manure acts as a slow release fertilizer and an excellent soil conditioner.

Microbes that drive the composting process require optimum conditions of temperature, moisture, oxygen, and carbon:nitrogen (C:N) ratio. The C:N ratio of 50:1. With the addition of bedding material (high carbon content), the C:N ratio will be even higher. Therefore, N has to be added to the manure for it to compost properly. The addition of grass clippings, hay, or fertilizer should bring the C:N ratio into the optimum range. When microbes work properly, the compost temperature will be between 120 and 160 F. Cooler temperatures result from a lack of N. When the composting process is complete, the temperature will cool naturally.

It is important to have the right balance of moisture and air for the microbes to process the manure. The compost should be moist but not soggy, and may need to be watered or covered with plastic to maintain moisture. Aerate the compost by turning it regularly. The manure and bedding particles should be about one-half inch to one and a half inches in size.


Land Application – Record keeping is an essential factor in land application of manure/compost. It is critical to know how much manure/compost was applied to each field and when it was applied. Analyze manure/compost regularly and record the lab results for future reference.

Do not apply manure to land that is highly erodible frozen or saturated. To protect water sources from manure runoff, do not spread manure within at least 150 feed of water source (such as a well, creek, or pond). Incorporate manure into the soil as soon as possible. Incorporating manure (mixing the manure with the soil) immediately reduces losses of manure nutrients to runoff and volatilization, and reduces odor problems associated with manure left on the soil surface.

Base the manure/compost application rate on crop N needs and available soil and manure N levels. Test your soil and manure for N levels at a certified laboratory. In general, the higher a crop yield goal, the greater the N needs. Irrigated crops also tend to need more N.


Virtually no viral diseases are transmitted between horses and humans through fecal material, but some bacteria and protozoan (such as E.coli and Giardia) can be transmitted in this manner. In addition, horse manure runoff into waterways may produce fecal coliform contamination levels that can be potentially hazardous to fish and anyone who drinks that water.

Runoff – Runoff water from dry lots, pastures, and manure storage or compost areas carries pollutants (such as nitrogen, phosphorus, and bacteria) into surface waters. Avoid over irrigation of pastures. Build berms or trenches to prevent water from entering or leaving dry lots and manure storage and composing areas.

Insect Control – Excellent fly-breeding conditions occur in mixtures of manure, spilled feed and decaying bedding. To help eliminate these areas, remove and spread the manure regularly and prevent accumulation of their wastes. Composting at proper temperatures inhibits fly development. Several pesticides can be used on manure piles to kill maggots.

Salinity – Manure tends to be high in salts, which when land applied at excessive rates, contribute to soil salinity. Soil salinity causes plants to become water stressed or, in extreme cases, die. When manure is not soil-incorporated, as in applications to pasture, the salts accumulate on the soil surface unless they are leached into the subsoil.

The Law

You are responsible for managing manure to protect surface water and groundwater. Federal and state laws forbid discharging animal wastes into water. Would you believe that manure management could increase your property values? If you are selling your property, manure facilities can be an asset under today’s regulatory requirements.

Colorado State University Extension Service offers workshops, publications, and over the phone assistance on manure management and composting.