Category: Manure Storage

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Storing Manure on Small Farms

Why Do Small Farms Need Manure Storage?

Accumulated manure can cause health, odor, pest, and water quality problems if not properly managed. One option is to collect the waste daily, load it in a spreader, and spread it on cropland, hayland, or pasture (often referred to as a “daily haul” system). This is time consuming and also has to be done regardless of the soil moisture, weather, or time of year. Spreading during rain, on saturated or frozen soils can cause compaction or lead to offsite runoff of manure. Growing crops can also be damaged during spreading.

The alternative to daily spreading is to stockpile or store the manure for a period of time, at which point it may be spread or hauled away and utilized beneficially elsewhere. Even though the number of livestock on your farm may not be large, enough manure will be generated to pose a problem if planning is not done.

Example: A single horse can produce 50 pounds of manure per day which translates to 11 cubic yards and 9 tons annually. The manure and bedding produced by this horse in a year can exceed 25 cubic yards. This would require a storage area of about 12 feet by 12 feet with an accumulated depth of 3 to 5 feet for one year of storage, depending how much decomposition and compaction of the manure takes place.

For more, see Manure Production and Characteristics to calculate the amount of manure produced by common farm animals.

Principles of Manure Storage

Regardless of the type or size of manure storage, there are a few basic principles to always follow:

  1. Keep the clean water clean. Any up-slope surface run-on should be diverted around the manure storage or animal lots by creating a small berm. Rooftop water can be directed via gutters, downspouts and possibly underground outlets so that it goes around animal lots and manure storage.
  2. Treat the dirty water. Any rainfall landing on the manure pile or the livestock concentration areas should (preferably) be retained in the structure or settling basin. Over time, the water evaporates, leaving behind the solid materials to be collected and spread on fields. The liquid can also be directed to a treatment area, such as a well vegetated filter strip. The plants will slow the flow, settling solids (filtering the runoff) and utilizing the nutrients as they grow. This option requires regular management as the liquid flow may eventually cut a channel and create an unobstructed path to creeks, streams, ponds or other clean water. The solids from the manure may also accumulate and smother the vegetation. The goal is to direct the drainage over the vegetated area as evenly (like a sheet) as possible and regularly harvest the vegetation as hay or silage to remove prevent build up of nutrients.
  3. Avoid flood-prone areas. Flood waters that can reach a manure storage location will transport manure downstream and cause extensive water quality problems.
  4. Accessibility. Store the manure where it is easily accessible to load and unload. Efficiency is important in order to properly manage the manure facility. Make sure you can access the site in all types of weather conditions. If it is difficult to access the site, you are less likely to regularly manage or maintain it.
  5. Avoid steep slopes when siting your storage location. The steeper the slope, the more difficult it is to manage the storage area, and the greater potential for offsite runoff. It may be necessary to build a small dirt berm (do not use manure for the berm) to prevent storm water from leaving the area and running downslope.
  6. If you spread the stored manure on your own land, do so following a nutrient management plan that establishes the spreading rate per acre to match the nutrients available in the manure to the needs of the crop.

Manure Storage Considerations

Storage can be very simple or quite complex; very inexpensive or quite pricey. The choice depends on a number of factors.

Storage siting

The first thing to decide when contemplating storage is the location. The spot has to be very convenient to the animal housing, but there is more to consider. The storage must be located well outside of any stream floodplain, and should have a slight slope for drainage, but not slope so much that runoff can cause problems. It is important to prevent manure from being washed offsite to streams or lakes. Manure contains potential pollutants when it is not managed correctly. The bacteria, phosphorous, nitrogen, and organic matter pose risks to aquatic organisms and humans.

Odor management is another consideration when siting a storage facility. Look at wind direction as relates to dwellings. The final consideration is aesthetics. If possible, keep the facility out of view of neighbors and passers-by. Sometimes a screen of trees and shrubs can help, and also may reduce odor.

Storage sizing

The sizing of a storage facility depends upon three factors:

  • How many animals are on the farm, and how much of the manure is collected?
  • What is the time period the storage will be accumulating manure before emptying?
  • How much money is available for building the facility?

From the weights and volume cited above for a single horse, it is easy to see how a storage facility can get large quickly, with just a few animals. Also consider that the ideal length of time permanent storage should have capacity for is six months; the minimum should be 3 months. For information on how to calculate the amount of manure produced, visit Manure Production and Characteristics.

Options for Manure Storage

Stockpiling

Cost: Low
Stockpiling of manure is just what it sounds like- simply taking the solid manure and soiled livestock bedding and piling it up in a convenient location. This primitive method can be acceptable for the farm with just 1 or 2 horses or several sheep. However, the spot must be compacted and sealed so that rainfall landing on the pile cannot leach pollutants into the soil and ground water. Sometimes gravel in a packed pad works well, or stone dust is used. The area approaching the pad needs to be firm also to prevent rutting in wet periods. Also, the pile should have a very slight slope (1-3%) to facilitate drainage to a vegetated filter strip.

A stockpile can be covered with a plastic tarp to reduce odors, flies, and leaching concerns. Rainfall will run off to the edges and never penetrate the pile. The tarp will need to be anchored securely all around the edges. A filter strip of vegetation or (preferably) a small dirt berm is still needed on the downslope side.

a concrete manure storage structure on a small horse farmDry Stack

Cost: Moderate
This is probably the most common and practical choice for the small livestock operation. A dry stack facility has three walls to contain the manure. The best ones have a poured concrete floor. The floor is slightly sloped for drainage out of the facility, and the drainage runs to an adjacent vegetative filter strip. The walls of a dry stack facility will be a minimum of four feet high. The walls, especially the back one opposing the entry, must be stout since the manure will be exerting outward pressure as the pile grows higher. Also, clean out is usually done with a front-end loader, and pushing will be done as the manure is scooped up. The walls can be poured concrete, cinder block, horizontal timbers, or vertical timbers. Secure anchoring below the frost line is crucial.

Composting

Cost: Moderate to High
The treatment of raw manure through composting is gaining in popularity. The final product is crumbly, low odor and resembles rich topsoil. It is often highly marketable. Composting reduces the amount of available nutrients, kills pathogens, reduces odor, and reduces manure volume. However, it requires management. A pile of manure left alone is not composting- it is decomposing, which is a big difference.

Composting requires a balance of nitrogen, carbon, oxygen, and liquid. When things are running properly, the center of the pile will reach 140 degrees, which kills pathogens and renders a relatively stable product. An untended decomposing pile has a nearly anaerobic core that produces objectionable odors when broken into. Although the center is often hot, it’s not hot enough to sanitize. Composting requires taking the pile’s temperature, and turning of the pile regularly to mix and aerate. Sometimes it will need water; other times it will need to be covered so it does not become saturated and lower the oxygen level to unacceptable levels.

Turning the pile is usually done with a small tractor equipped with a front bucket loader. There are many ways to set up the composting site. It could just be several long windrows, 4 – 6 feet high, on compacted ground or compacted gravel, or concrete. Or, there may be several small dry stack-type bays connected together side by side, and the manure is moved from one bay to the next, and the manure is mixed and aerated in the process. Manure and bedding, when properly mixed, can be transformed into compost in as little as six weeks.

For more information: Composting Livestock or Poultry Manure

Liquid Storage

Cost: Highest
Liquid storage is used by many larger dairy or swine farms. The waste is diluted with stall wash water and pumped to a lagoon or other holding location. From there the liquid effluent and the solids are pumped into an injector tank and spread in the field as a slurry, either sprayed on the surface or injected into the soil. Or, the effluent is spray irrigated and the solids are separated and spread in a conventional fashion. This type of storage and management system is usually the most complex and expensive, and is usually not practical for smaller livestock operations.

For more information: Liquid Manure Storage Treatment Options, Including Lagoons

Hauling Away

Sometimes, the best solution is to simply have a dumpster or some other form of semi portable holding structure, and place the manure in there. When needed, a waste management purveyor can pick it up for beneficial re-use on cropland that can use the organic matter and nutrients. Remember to still have a vegetative filter strip to treat the leachate draining from the dumpster as it drains away.

If the amount of manure being generated daily is small enough, a small manure spreader can serve as the storage device. When full, simply hook up the tractor and spread the waste in the cropland or hayland according to a nutrient management plan. Caution, though- if applying to pastureland, it is important to spread the manure about four weeks before a grazing cycle. Smothering of grasses can occur if the manure is applied too heavily. Parasite eggs in raw manure may cause an infestation problem on pastures.

Vegetated Filter Strip

It is crucial to have a vegetated filter strip to treat the runoff water coming from a manure pile or a concentrated livestock area. The combination of grass uptake, soil filtering and adsorption, and biological processes in the top inches of soil significantly reduces pollution potential of manure runoff. The filter should be established in a vigorous, thick stand of grasses adapted to the soil conditions at the site. Animals should be kept off of it, and it should be hayed at least twice a year to remove nutrients and encourage growth. On a flatter slope, the strip should be a minimum of 30 feet wide, wider if slope is steeper. A better option than a vegetative filter strip is a Vegetative Treatment System. See the article on What is a Vegetative Treatment System? or a runoff containment. To see all the runoff control options, see Do I need to control the barnyard or lot runoff on my small farm?

Managing Stockpiled Dry Manure on Small Farms

Flies and odors from stored manure can be reduced if good management is practiced.

  • Keep the manure as dry as possible.
  • Remove manure from the farm regularly during fly breeding season.
  • Try not to use insecticides or larvacides; naturally occurring fly predators- tiny, non-stinging wasps and parasites, are beneficial to the pile. Wasps are active during fly season and their activity is better in dry manure.
  • When cleaning out the storage, leave a couple of inches of dry manure over the bottom of the storage area to provide a population of fly parasites and predators. Manure removal can be staggered to leave one section per week to supply fly predators and parasites.
  • Remove a winter’s stockpile of manure during cold weather (<55°F) before fly breeding season.

Barnyard and Corral Management

Manure should not only be removed from stalls and barns, but corrals, barnyard areas, and sacrifice areas should be regularly cleaned to reduce flies, odor, and the potential for mud. A box scraper, skid loader, or tractor and loader can be used to remove manure built up on the surface of these areas. For more information, see the following publication: Sacrifice Areas.

Author: Fred Kelly, USDA Natural Resources Conservation Service, New Jersey

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Solid Manure Sampling Procedures

Developing a nutrient management plan depends on testing manure for nutrient content. Your manure test results are only as good as your sample. This page outlines recommended ways to sample solid manure from open feedlots.

Sample During Loading

The recommended sampling for solid manure is to sample while loading the spreader. Sampling the manure pack in a barn directly has been shown to result in very variable results and is not recommended. Take at least 5 samples during the process of loading several spreader loads and save them in a bucket. When all of the samples are collected, thoroughly mix the samples and take a subsample from this to fill the lab manure test container.

Sample Manure During Spreading

Spread a tarp or sheet of plastic in the field and spread manure over this with the manure spreader. Do this in several locations and with several loads of manure. Collect the manure from the tarp or plastic sheet in a bucket. Mix the manure collected from different locations and spreaders, and take a subsample from this to fill the lab manure test container. This procedure is usually only practical for more solid manures.

Photo courtesy USDA NRCS

Sampling Daily Haul Manure

Place a 5 gallon bucket under the barn cleaner 4 or 5 times while loading the spreader. When all of the samples are collected, thoroughly mix the samples and take a subsample from this to fill the lab manure test container. Repeat this several times throughout the year to determine variability over time.

Sampling Manure in a Poultry House

Collect 8-10 samples from throughout the house to the depth of the litter to be removed. Samples near feeders and waterers can be very different. Collect samples from these areas proportional to the space they occupy in the house. When all of the samples are collected, thoroughly mix the samples and take a subsample from this to fill the lab manure test container. A sample taken while loading the spreader or during spreading is likely to be a more representative sample.

Sampling Stockpiled Litter

Take 10 samples from different locations around the pile at least 18 inches below the surface. When all of the samples are collected, thoroughly mix the samples and take a subsample from this to fill the lab manure test container. Large diameter auger bit and portable drill or soil sampler can be used to access manure deep within pile.

Taking a sample from a manure stockpile Taking representative sample from all subsamples mixed together in a bucket

Sampling stockpiled manure. Picture Source: Manure Testing for Nutrient Content

Sampling Manure from an Open Lot

These videos were produced by the Iowa Learning Farms project.

Sampling Stockpiled and Composted Manure

Related Web Pages

Overview of Manure Testing

Page Authors: Douglas Beegle, Penn State University and John Peters, University of Wisconsin

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Liquid Manure Sampling Procedures

When testing manure, your nutrient management plan is only as good as your ability to obtain a representative sample. In liquid manure storage, agitation is critical to spreading uniform manure and to getting a representative sample. Agitating for 2-4 hours is the minimum. Depending on the type of storage longer agitation times may be required. The agitation for sampling should be similar to the agitation done when the storage is emptied. For this reason the most practical time to sample is when the storage is being emptied for field application.

If the storage is not adequately agitated there will likely be stratification. The figure below illustrates how manure analysis can vary within a storage without adequate agitation. In this example manure in the last 15 loads spread from this storage has 2 to 3 times more phosphorus than in the first 45 loads spread. If the storage is known to be stratified, separate samples should be taken as the manure consistency changes during emptying.

diagram

cc2.5 Les Lanyon

Sampling As Manure Storage Is Emptied

Agitate the storage thoroughly before sampling. Use a bucket to collect at least 5 samples during the process of loading several spreader loads and save them in the bucket. When all of the samples are collected, thoroughly mix the samples and take a subsample from this to fill the lab manure test container. When filling containers with liquid manure never fill the container more than ¾ full. If samples are collected over a several hour period, the bucket with manure sample should be stored on ice to limit ammonia losses.

Sample Manure When Pumping From Storage. Photo courtesy of Ontario Ministry of Agriculture, Food and Rural Affairs. Photo Source: http://www.thecattlesite.com/articles/1307/sampling-liquid-manure-for-analysis


Sampling From the Manure Storage

Picture Source: http://www.extension.iastate.edu/pages/communications/epc/Winter02/manure.html

Sampling a storage directly is much more difficult and likely to result in more variable results than sampling as the manure is loaded into the spreader. Agitate the storage thoroughly before sampling. Use a small bucket or tube to collect at least 5 samples from different locations in the storage. Combine these samples in a bucket and thoroughly mix the samples and take a subsample from this to fill the lab manure test container. When filling containers with liquid manure never fill the container more than ¾ full.

Liquid Manure Sampling Video

This video from the Iowa Learning Farms Project shows two sampling techniques for liquid manure storage prior to agitation. As indicated above, samples of agitated liquid manure should be obtained when possible, but in cases where the information from the lab analysis (which can take several days) is needed before manure can be applied to crop land.

Part 2: Sampling Liquid Manure

Sampling Manure During Application

This method is good for irrigated manure. Place buckets around the field to catch manure from the spreader or irrigation equipment. Place these to collect manure from more than one spreader load. Combine and mix the manure collected from different locations, and take a subsample from this to fill the lab manure test container. This method may give you “crop available ammonia nitrogen” as any ammonia losses may have already occurred prior to reaching bucket. What reaches the bucket is likely to soak into the soil and be available to the crop.

Related Web Pages

Overview of Manure Testing

Page Authors: Douglas Beegle, Penn State University and John Peters, University of Wisconsin

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Calibration of Manure Application Equipment

In order to beneficially apply nutrients contained in animal manure to crops and to protect the environment, it is necessary to calibrate land application equipment. In addition, many states require calibration of manure application equipment on a regular basis via regulations and permitting requirements. Records of calibration results may be a requirement of your permit.

Calibration Procedures Will Vary

Depending on the type of manure or the type of equipment being used to apply manure, there are different calibration procedures to follow. See the following pages for information on specific procedures.

Calibrating Manure Application Equipment Makes Economic and Environmental Sense

Proper calibration of manure application equipment is necessary to insure that field application rates are consistent with nutrient management plans. As nutrient plans have attempted to more accurately balance nutrient supplied by manure and fertilizer and crop requirements, calibration is also critical to avoid under applying nutrients and reducing yields.

Properly calibrated and operated equipment will help eliminate:

  • ponding or runoff of manure into waterways
  • leaching of nutrients and pathogens into shallow groundwater
  • accumulation of nutrients or metals in the soil
  • reduced crop yields from insufficient nutrients

Manure is a valuable resource that should be applied in an ecological and environmentally sensitive manner. As the value of the nutrients in manure increases due to increases in commercial fertilizer cost, calibration of manure application equipment becomes even more important.

Other good reasons to calibrate are to monitor equipment performance changes over time (wear and tear) so that timely maintenance is performed, and to troubleshoot any equipment operational problems. Calibration should be done annually even if regulatory requirements require less frequent calibration. Also, it is a critical to re-calibrate when the consistency or liquid content of the waste changes considerably as changes in material characteristics can change the performance of the application equipment.

Tractor

cc2.5 Garry Grabow

Important Considerations for Calibrating Manure Application Equipment

Calibration of equipment used to land apply manure considers two aspects:

  1. the amount of manure (nutrients) applied, and
  2. how uniformly the manure is applied over the field.

Some nutrient management plans may be based upon nitrogen limited application, while other will be based on phosphorus limited plans; regardless it is critical to know the amount and uniformity of applied manure. Depending upon the equipment used, calibration will involve field measurement of flow or unloading rates, equipment speed and settings, operating pressure, application width, and application overlap.

Manure application equipment can be categorized into three types:

Application equipment varies depending upon the type of manure, e.g. lagoon liquid, poultry litter, or fresh manure. Calibration of each type of equipment will vary in which measurements are required and how application rate and uniformity are quantified and assessed.

Recommended Educational Resources

Author: Garry Grabow, North Carolina State University
Reviewers:Marsha Mathews, University of California-Davis, Rick Koelsch, University of Nebraska, and Doug Beegle, Pennsylvania State University

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Calibrating Solid Manure Application Equipment

Why should you calibrate solid manure spreaders? Simple, because you should know how much manure was applied to your fields. Combined with a manure testing program, you can calculate the amount of manure nutrients that were applied. This can save money on commercial fertilizer purchases AND improve water quality. Related: Calibrating liquid manure spreaders and irrigation equipment.

What Can Cause Manure Application Rates to Change?

Solid spreaders can have poor uniformity if operated improperly, so proper operation and calibration of these types of systems are critical. The system needs to be recalibrated if any of the following are changed:

  • Tractor speed
  • Gate opening (and spinner settings for spinner spreaders)
  • RPM
  • Width of spread
  • Manure characteristics
  • Wind
  • Slope
  • Operator (experience and consistency)

It is helpful to know the capacity and setting ranges available with solid spreaders. Solid spreader capacity is noted in the manufacturer’s specifications and may be listed in tons, cubic feet or cubic yards. Capacity is normally listed in struck level (flush with top of unit) height but may also be rated in “heaped” load.

This video shows how tarps that are laid out and manure spread on them can be collected and weighed. it was produced with smaller farms in mind, but the concepts and procedures apply to equipment of all sizes. Produced by: Rutgers University Cooperative Extension.

What Are the Steps in Calibrating Solid Manure Spreaders?

This video shows a process for weighing the  manure spreader and measuring the area over which manure was applied. The worksheet referenced is Know How Much You Haul Produced by the University of Wisconsin Cooperative Extension.

Tarp Method

Normally calibration of solid spreaders will involve collecting the discharged manure in a tarp to determine application rate and collecting manure in a series of pans laid across the travel path to assess spread pattern, uniformity and to adjust pass width. Click on the following link for an illustration of the procedure for this method. (Source: Rick Koeslch, University of Nebraska). Manure density is normally determined to allow conversion from volume to weight (e.g. tons) applied.

Weighing the Spreader

If manure spreader capacity can be weighed, then the only field measurements required are distance traveled to empty the spreader and width of spread pattern (or distance you move laterally with each pass through the field). From that information, a fairly simple estimate of application rate can be made.

Moisture content of manure has a large impact on manure density and actual spreader capacity. When calibrating, it is important to correctly interpret the nutrient analysis reports provided by the analytical lab. Some analyses report manure nutrient concentration at the moisture content submitted. Other analysis reports may give the nutrient analysis at a moisture content that is different than either the sampled material or the material to be applied. For accurate calibration, match moisture content of manure samples with moisture content of the manure being spread.

Adjustments to achieve the proper application rate and uniformity include adjusting travel speed, gate openings and hammer clearance, and adjusting spinners for spinner spreaders. Narrowing the effective width (pass distance) generally increases application uniformity but also increases application rate.



Types of Solid Manure Application Equipment

Manure is generally handled as a solid at a solids content of 20% or more. Solid manure spreaders come in various types. Spinner spreaders use spinning disks at the rear of the unit to propel the manure, box spreaders use a paddle and/or auger to discharge manure from the rear of the unit, and side discharge spreaders typically use augers and flailing hammers to “throw” the manure out the side of the unit. Spinner spreaders are used to apply poultry litter and are widely used as commercial fertilizer applicators. Side discharge units can handle materials with a wide range of moisture contents. Rear discharge spreaders are commonly used with scraped manure solids from open lots and manures with significant bedding.

Recommended Educational Resources

Author: Garry Grabow, North Carolina State University
Reviewers: Marsha Mathews, University of California-Davis, Rick Koelsch, University of Nebraska, Doug Beegle, Pennsylvania State University

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Calibrating Irrigation Equipment for Manure Application

Irrigation equipment can be used to land apply manure with a solids content of up to 2-3 percent depending upon the type of equipment used and nozzle size. The types of systems typically used are stationary (also called solid-set), traveling guns, and center pivots. Irrigation equipment is typically used to land apply liquid manure from anaerobic lagoons and runoff holding ponds. If applied manure is undiluted, calibration requirements may differ slightly from those systems using diluted manure. If manure is diluted with freshwater, nutrient concentration must be adjusted by the dilution ratio when calculating nutrient rates. Always check with your state regulatory agency for calibration and reporting requirements.

Related: Calibrating solid manure spreaders and irrigation equipment.

As with the other types of equipment used for land applying manure, calibration consists of verifying application rates and application uniformity. Application rate and uniformity is measured by collecting applied manure in rain gages that are placed in a line for traveling gun and center pivot systems or in a grid for stationary systems. Systems using undiluted manure may require measurement and reporting of application rate from the gun or nozzle and not what is collected in a rain gage if plant available nutrients are calculated to include evaporative losses and volatilization.

If measuring application rate from the gun, a flow meter or pressure measurement at the nozzle and a manufacturer’s performance chart for the gun/sprinkler and nozzle will be required. Collected depths are used to calculate commonly-used measures of irrigation equipment uniformity such as the Christiansen uniformity coefficient (CU or Uc) or distribution uniformity (DU). Details of how to setup uniformity evaluations and calculate measures of uniformity and application rates are given in the links in a paragraph at the end of this document.

Uniformity of irrigation-type equipment can be affected by:

  • Operating pressure
  • Nozzle condition
  • Pump impeller condition
  • Wind
Center pivot irrigation

It is important that these types of systems be operated as designed. Normally this means that pressure and flow rate should be field-verified in the calibration procedure and compared to the design values or the ranges recommended by the manufacturer. Pressure should always be measured at the nozzle, not at the pump or other location. Pressure can be measured either with a pressure gauge mounted on the sprinkler riser or mounted on the gun body (for big guns) or measured using a pitot tube placed directly in the nozzle stream. For center pivots with drop nozzles, pre-set pressure regulators are normally located on the drop tubing, so nozzle pressure is known. In addition to pressure and flow rate measurement, the wetted diameter of the sprinkler or gun (for solid set and traveling gun systems respectively) should be measured.

It is generally recommended that flow rates be within 10 percent of the design rate, and that wetted diameter be within 15 percent of that specified in the manufacturer’s chart at the measured nozzle pressure. Flow rates may be obtained either by using a flow meter or by using values obtained from the manufacturer’s chart at the measured pressure. For animal waste systems, flow meters are normally temporarily placed in the main irrigation line either in-line or temporarily strapped on depending upon the type of flow meter used.

Adjustments to achieve the proper application rate and uniformity include adjusting operating pressure, travel speed (for traveling gun or pivot systems), replacing worn nozzles, and operating systems when there is little wind. Changes in equipment (e.g. nozzle size) should not be done without consultation with an irrigation specialist.

Recommended Educational Resources

Author: Garry Grabow, North Carolina State University Reviewers: Marsha Mathews, University of California-Davis, Rick Koelsch, University of Nebraska

Photo: CC 2.5 Charles Fulhage or Joe Harner

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Calibrating Liquid Manure Application Equipment

Types of Liquid Manure Application Equipment

Liquid manure application equipment includes tankers (sometimes called honey-wagons) and hose-drag (also referred to as drag-hose) systems. Depending upon the type of liquid application system being calibrated, calibration may require weighing the tanker, recording the time to empty a load, measuring application spread width and length and/or recording equipment speed. Also, with some calibration methods, determination of manure density is required.

Related: Calibrating solid manure spreaders and irrigation equipment.

Important Factors For Making Calibration Calculations

Normally calibration requirements are specific to the equipment, i.e. one piece of equipment needs only to be calibrated once during the calibration interval, often annually. However, it is a good idea to calibrate equipment that may be used under different conditions. For instance, adding more hose to a hose-drag system when moving from one field to the next can increase friction loss and alter manure flow rates though the applicator. It may also be valuable to calibrate for multiple travel speeds, each representing a different application rate. This allows one to select an application rate that most closely matches the nutrient requirements of individual fields or crops.

It is important to select the calibration procedure that is consistent with your manure analysis. For instance some analysis reports nutrients in a weight per volume measure (e.g. pounds per thousand gallons) while some analysis is provided on a weight per weight basis (e.g. pounds per ton). Calibration of liquid tanker spreaders can be done by weighing a load or knowing the capacity (volume) of the spreader as specified by the manufacturer. Conversion between volume and weight may be done by determining the manure density.

By knowing the spreader capacity, distance traveled to empty the spreader, and width of spread pattern (or distance you move laterally with each pass through the field), a fairly simple estimate of application rate can be made. This should be repeated several times to determine an average application rate each manure source. The speed of the tractor can be varied to adjust the application rate to achieve the planned application rate(s). The general procedure for calibrating a liquid manure tanker spreader is illustrated in the following file Liquid Spreader Calibration.

Hose drag type systems are calibrated by measuring tractor speed, flow rate of the manure through the system and effective width (distance between passes). These factors allow conversion to volume of manure over area applied, e.g. gallons per acre.

Calibration of hose-drag (drag-hose) equipment requires measurement of (a.) tractor speed, (b.) spread width (We in illustration) and (c.) flow through the hose. Photo: Garry Grabow, All Rights Reserved.

Recommended Educational Resources

Author: Garry Grabow, North Carolina State University Reviewers: Marsha Mathews, University of California-Davis, Rick Koelsch, University of Nebraska, Doug Beegle, Pennsylvania State University

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Liquid Manure Storage Ponds, Pits, and Tanks

Waste storage pits and indoor tanks are generally under-floor inside the dairy, swine (and sometimes poultry) housing. Waste storage ponds and above ground storage tanks are fenced and posted to keep young children, livestock, and other unauthorized visitors away. Pond banks are seeded or sodded with a good grass cover to prevent soil erosion and mowed regularly to control grass and weed growth.

Recommendations for siting, design, and construction of manure storage units are provided in ASABE Technical Library EP393.3 Manure Storages. These recommendations are for both earthen and fabricated structures.

Storage Volume

Storage volume considerations include daily animal manure and related wash/flush water inputs. Dairy cattle generally generate larger manure volumes per live weight than swine, beef, or poultry. A mature dairy cow weighing 1,400 pounds can generate around 14 gallons (about 120 pounds or 1.9 cubic feet) of feces and urine each day with an average as-excreted solids content of around 12 percent.

The total excrement for cows housed in freestall total confinement, along with milking wash wastes would bring the total to more than 2.5 cubic feet per cow per day. For 100 cows, this is nearly 9 tons and 9+ cubic yards of manure per day. For cows on pasture part-time, manure handling and storage needs would be less and in direct proportion to actual confinement time. A 100-cow herd on half-time pasture would accumulate nearly 5 cubic yards (4.5 tons) of manure per day in confinement, including milk wash wastes. This daily manure volume for the confinement operation is multiplied by the planned storage period days to get the manure storage volume for the planned storage period.

Outdoor Storage Pond Volume

Outside storage pond or uncovered tank volume must also include expected rainfall minus evaporation from the storage surface. In high rainfall areas like the Southeastern US this could be 12 to 14 inches annually. In all geographical locations, this is based on the planned storage interval worst case and on local rainfall and evaporation figures. Volume must also include space for the 25-year-24-hour rainstorm event and any resulting watershed runoff into the pond. Roof and other rainfall runoff may or may not be included, depending on whether dilution water is needed for irrigation or not needed for tank wagon application of dairy waste.

In addition, the volume of the storage pond should also include an allowance of at least 1 foot of freeboard above expected full level for overflow cushion protection and an allowance of at least 2 feet of depth on the bottom of the pond for materials not removed during the normal agitation-pumpout procedure. Storage pond pumpout must be carried out within the planned storage period. Pumpout should be started in time to insure that space is available to hold the 25-year-24-hour rainstorm.

Irrigating with Animal Waste

Waste irrigation equipment or tank wagons and specially designed pumps must be available, with tractors large enough to handle the horsepower requirements. Both agitation before pumpout and manure solids handling pumps matched to either the slurry irrigation system or “honey wagon” transfer tank are critical to successful waste storage pond pumpout. See the figure below for a cross section of a waste storage pond. Note the upper pumpdown stake. Pumping should begin when water reaches this level.

Cross section of a waste storage pond. Contributed to eXtension CC2.5

Irrigating with slurry calls for special equipment designed to handle both the high solids content and high fertilizer content of the waste.

Related Web Pages

Recommended Reading About Manure Storage Ponds, Pits and Tanks

Research Summaries

Page Managers: Ted Tyson, Auburn University, tysontw@auburn.edu and Saqib Mukhtar, Texas A&M University, mukhtar@tamu.edu .

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Lesson 24. Operation and Maintenance of Manure Storage Facilities

The LPES Curriculum CD available from MWPS contains all lessons at print quality resolution, is searchable, and includes an index and PowerPoint presentations for each lesson. A full, printed version is available as is a 2-CD set of the lessons in PageMaker format. For more information or to purchase LPES materials, contact MWPS by phone at 1-800-562-3618, by fax at 1-515-294-9589, or by e-mail at mwps@iastate.edu

View Lesson 24 (PDF file). Individual sections can be accessed below.

Intended Outcomes

The participants will

  • Practices and operations necessary to maintain environmentally sound manure storage facilities.
  • Significance of a pumpdown marker and maintaining a liner.

Contents

Activities

The participants will

  • Estimate manure-handling requirements (pumpdown/hauling time and frequency).
  • Develop a manure storage inspection checklist.
  • Develop a record-keeping plan for self assessment or as required by regulation.

Authors: Charles Fulhage and John Hoehne

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Manure Collection and Handling Systems

Manure storage and handling systems enable livestock producers to efficiently utilize all the components in their manure management system. A typical manure management system will include some or all of the following components.

  1. Area where manure is produced (ie. feedlot, freestall barn, confinement building).
  2. Manure treatment area (solids separator, digester, aerator).
  3. Manure storage facility (manure tank, holding pond, stackhouse).
  4. Manure utilization area (crop fields).

The purpose of manure collection and handling systems is to efficiently gather and move manure among these components of a manure management system.

Manure Collection and Handling Equipment

The type of equipment and procedures used to collect and handle manure depends primarily upon the consistency or “thickness” of the manure. The term “solids content” or “percent solids” is often used to describe this characteristic in manure. Different species of livestock excrete manure with different percent solids.


As can be seen in Figure 20-1, the percent solids of manure excreted by swine, beef and dairy falls within a rather narrow range (10 to 13 percent solids), while poultry manure is excreted at a considerably higher solids content. The solids content of excreted manure is often changed by such processes as adding bedding, drying manure on a lot surface, adding washwater or dewatering the manure by solids separation.

The terms “solid” (greater than 15% solids), “slurry” (5 to 15% solids) and “liquid” (0 to 5% solids) are typically used within the livestock industry to describe the characteristics of a particular manure. Solid manure will “stack” to some degree with minimal seepage of free water from the pile depending upon moisture content. Slurry manure has fluid characteristics and tends to flow like a thick chocolate malt. Liquid manure has flow characteristics similar to that of water.

The following pages contain additional information related to each manure type.

Recommended Reading on Manure Collection and Handling Systems

Authors: Charles Fulhage, University of Missouri, and Joe Harner, Kansas State University

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