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

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

Solid Manure Application Equipment

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How is solid manure applied to cropland?

The most common equipment for applying solids to the land is a rear-discharge, box-type spreader equipped with beaters that broadcast the manure over a width of several feet (see Image 1).

Usually, the manure is conveyed to the beaters at the rear by slats attached at each end to a sprocket-driven chain. Some use a powered front end-gate to push the material to the beaters at the rear. To handle semisolid manure, a tight-fitting, closable rear end-gate is required.

Some spreaders have a side discharge; most of these have V-shaped hoppers and feed the material to the discharge with augers. A rotating expeller slings the material out of the discharge port. The application rate is varied by an adjustable gate opening, usually operated by a hydraulic cylinder.

Flail-type spreaders have a semicircular hopper bottom and a rotating shaft with chain-suspended hammers to fling the material from the hopper. The flail-type and the side-discharge spreaders are adapted to both semisolid and solid manure.

Image 1: Broadcasting manure on cropland.

Manure spreaders may be tractor-drawn models or they may be mounted on a truck. Most tractor-drawn spreaders are PTO operated, but some are driven from the ground wheels. Some are hydraulically powered for greater speed variation, especially for the apron drive, to vary the application rate. In the past, spreader capacities varied from about 30 to 400 cubic feet with tractor horsepower requirements ranging from 10 to more than 120.

Recommended Reading About Land application of Manure

Land Application Equipment for Livestock and Poultry Manure Management

Authors: Jon Rausch, Ohio State University and Ted Tyson, Auburn University.

Liquid Manure Application and Irrigation Equipment

Liquid manure application to crop land

Direct injection of liquid animal manure
Direct injection of liquid animal manure

Liquid animal manure is land applied using liquid manure tankers or irrigation equipment. Liquid manure tanks are frequently pulled, much like a wagon, behind a tractor or mounted on a truck or other power source. Pull type tanks range in size from less than 1,000 gallons to over 8,000 gallons. Those that are mounted on a truck are generally between 3,000 and 6,000 gallons. Truck mounted tankers make over the road travel quicker and safer.

Drag-line direct injection of animal manure
Drag-line direct injection of animal manure

Liquid manure tankers generally discharge manure from the rear of the tank on the soil surface. Alternatively, various types of soil incorporation tools may be used and are generally mounted directly to the tanker. Manure from the tank is distributed through a series of hoses and discharges through the soil incorporation tool. Soil incorporation of liquid animal manure can minimize odors and conserve nutrients.

Irrigation of wastewater by hard hose traveling gun
Irrigation of wastewater by hard hose traveling gun

Land applications by sprinkler irrigation or by a drag-hose, tractor-mounted applicator are the current practical methods of applying large volumes of lagoon effluent or contained lot runoff. Drag-hose applicators can decrease odor problems and the loss of ammonia nitrogen to the air by incorporating the manure. The advantages of sprinkler irrigation include reduced cost because of lower energy and labor requirements.

Lagoon wastewater applied by pivot irrigation for hay production
Lagoon wastewater applied by pivot irrigation for hay production

Labor requirements can be further reduced by permanently installed underground pipes to sprinkler risers, center-pivot irrigators or hose attachment points for traveling guns or drag-hose applicators. However, land application of manure slurry and lagoon effluent with irrigation equipment requires a higher level of management than other methods of spreading to avoid pollution and nuisance problems.

Recommended Reading on Liquid Manure Application and Irrigation Equipment

Authors: Jon Rausch, Ohio State University and Ted Tyson, Auburn University

Costs of Manure Application and Transport

When talking about the value of manure, costs are reported in terms of dollars. While reporting in terms of dollars is usually helpful, it is not the only metric for discussing costs. Any resource that is required to accomplish a task can be considered a cost. With this in mind, this page will discuss the cost of manure distribution in terms of dollars and time. The limiting resource, dollar cost or hours required, determines how manure is distributed. Hours could be converted to dollars but that would possibly obscure the management of these costs.

Factors Influencing Cost of Manure Management

The three major activities that influence the cost of manure management are loading, transporting and land applying. Each activity can require its own specialized equipment and can constrain the use of the manure. For example, except for an external manure storage structure, loading is best done when animals are not present and thus limited to those time periods. Transportation can be time consuming depending on the distance traveled and the amount of water hauled in the manure. Land applying requires proper soil and plant conditions and specialized equipment.

Livestock manure is either liquid, slurry or solid. Different types of manure will have different impacts on the cost of distribution. For example, solid manure can usually be hauled farther for less money because less water is being transported. Liquid manure, because of its high water content, can’t be transported as far but low cost irrigation systems can be used to distribute it relatively inexpensively. This page will address each manure type separately. Because the dollar cost of managing manure is so dependent on location, type of livestock, form of manure, availability of land, etc. No dollar estimate will be given in this page. The quickest way to get a cost estimate would be to contact a custom manure hauler and ask the price charged for different services.

The table below summarizes the relative costs of manure application and distribution. When reading it, compare the costs within a column, rather than within a row. In other words, use it to compare the cost of loading, transportation, or land application for each type of manure. The more dollar signs ($) a manure type has, the more expensive it is relative to the other types of manure. Click on a type of manure in this table to be taken to a description of why different manures will have different costs.

Summary of Manure Application and Distribution Costs
Manure Type Loading Transportation Land Application
Solid Manure      
Fresh $$ $$ $$$
Stockpiled $$$ $$ $$$
Slurry Manure      
Tanker $ $$$$ $$$
Dragline hose $ $$$ $$
Liquid Manure      
Dragline hose $ $$$ $$
Irrigation system $ $ $

Custom application

Because much of the equipment used in manure application is unique to manure application, many livestock producers choose to not own the equipment but rather hire custom operators to handle their manure. Custom operators can lower the cost of manure management, relative to owner operated equipment, by spreading the cost of expensive equipment over more units. Many custom operators can also apply the manure more quickly due to experience and because they have larger equipment or multiple pieces of equipment. Because they work for many livestock producers, they may not be able to apply an individual’s manure at opportune times. This uncertainty of when the manure will be applied is a cost that needs to be taken into account. Contracting Certified Manure Haulers contains instructions for comparing custom hauling with producer hauling of manure.

Livestock manures are an excellent source of organic nutrients. However, they are generally more expensive to transport and land apply than more concentrated commercial fertilizers. The cost of manure transport and distribution are critical to understand and manage in order to derive maximum value from manure. A research project completed in the late 1990’s includes this information. The actual costs presented may no longer be relevant but the conclusions are still valid.

A spreadsheet to estimate the cost of hauling various types of manure can be obtained at University of Missouri.

Related Web Pages

Authors: Ray Massey, University of Missouri and Josh B. Payne, Oklahoma State University

Costs of Slurry Manure Application and Transport

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Manure Value and Economics

Livestock such as dairy and swine often have slurry type manure. The manure is liquid but does not flow easily. It is either stored directly below the animal pens, or scraped or pumped periodically into a holding pen outside of the building.

Loading Slurry Manure

Loading slurry manure is accomplished with a pump powered by a tractor or stationary engine. The slurry can be loaded into tractor-pulled or truck-mounted tankers, or pumped through a hose attached to a tractor that applies it as it is being pumped from the pit. The cost of loading slurry is usually low because the pump can do it quickly and the volume per animal is not usually high.

Slurry Manure Transport

Transportation of slurry by tanker can be expensive because a lot of water is being transported and the same equipment that is hauling the slurry is usually land applying the slurry. When tankers are used, the number of hours spent transporting the slurry is frequently the limiting cost. The land may become unavailable to receive the slurry, due to crop planting times or soil conditions, before all of the slurry can be land applied. Often, the distance transported is limited so that the time constraints can be met.

If the slurry is pumped through a hose to the field, the transport time is negligible. As the slurry is pumped, it is simultaneously injected or surface applied to the land. The important cost becomes the cost of purchasing pipe and hose that is sufficient for this method of land application.

Land Application of Slurry Manure

The cost of land application of slurry varies with the type of equipment used. Tankers can be expensive to own unless they are used for many animals on many acres. There is a definite economy of scale with tankers. Additionally, the tankers usually require fairly large tractors or trucks. If the livestock owner does not have a cropping enterprise that requires the large tractor, ownership of the tractor for manure distribution alone becomes expensive.

Tankers are economical for large-scale operations with slurry manure.

When slurries are applied via hoses (called dragline hoses), a tractor pulled distributor is used to move the hose around the field so that the slurry is evenly distributed. The cost of the equipment can be very expensive, but the amount of time is decreased considerably compared to using tankers because most of the time is spent in applying the slurry. Very little time is spent getting into and out of the field, as is the case when using tankers.

Authors: Ray Massey, University of Missouri and Josh Payne, Oklahoma State University

Costs of Solid Manure Application and Transport

Poultry litter and beef feedlot manure are the most common types of “solid” manure. Separated solids from dairies can also be a source of solid manure. Solid manures must be scraped off the floor of the pen or house where the animals were raised. Scraping and loading onto trucks usually is done with a front end loader. If the manure is not land applied at the time the pens are cleaned, the manure can be stockpiled until needed. Poultry litter, in particular, when stockpiled is stored in covered sheds. The cost of the storage shed is an additional cost to manure loading.

Transport Costs of Solid Manure

As previously mentioned, solid manures are the least expensive to transport because most of the bulk transported is dry organic matter containing fertilizer nutrients (N, P and K). Water has little value in manure and adds a lot of weight that costs money to transport. Often, the manure is loaded into transport trucks that haul it to the receiving field, where it is unloaded and then loaded into an application truck.

Land application of solid manure. CC 2.5 Charles Fulhage or Joe Harner

Land Application of Solid Manure

Land application of dry manures is done with a flail type spreader. The manure, as it comes out of the truck-mounted or tractor-pulled spreader box, is flailed out in small pieces onto the surface of the soil. The spreader box is usually a specialized piece of equipment that can be expensive unless it is used to spread a lot of manure on many acres. If the manure needs to be incorporated into the soil, the cost of disking the manure into the soil could also be considered a cost of manure management.

Transportation Cost Assistance

To encourage appropriate use of the nutrients in manure, several government programs subsidize manure management costs. These programs can help reduce transportation costs, increasing manure value as it is more fully utilized as a soil amendment/fertilizer where it is most needed.

Examples of assistance include:

  • subsidy programs in Oklahoma and Arkansas that assist in moving poultry litter from nutrient sensitive watersheds to nutrient deficient areas;
  • loan guarantees to producers purchasing appropriate manure transportation equipment in Missouri;
  • USDA Environmental Quality Incentives Program (EQIP) that cost shares on certain manure investments depending on the priorities of each individual state.

Potential applicants for assistance programs could contact their local USDA Natural Resources Conservation Service office and state Departments of Agriculture or Environental Quality.

Authors: Ray Massey, University of Missouri and Josh Payne, Oklahoma State University

Page reviewers: Alan Lauver, NRCS and Chandra Theegal, Lousiana State University

Costs of Liquid Manure Application and Transport

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What Systems Produce Liquid Manure?

Liquid manures are most common with pork production where the manure is flushed from the building and stored outside in lagoons. Liquid manures are mostly water with some organic matter and nutrients suspended in the water. Most of the organic matter decomposes in the lagoons and is not removed.

Options to Haul and Apply Liquid Manure

While some livestock producers haul liquid manure in tankers, it is usually considered cost prohibitive. The amount of water is so great that the hours spent distributing it and the resulting dollar cost exceeds the value of the manure supplied nutrients when using tankers.

Liquid manure is usually pumped through pipes and hoses to the land that will be accepting the manure. This means that loading costs and transportation costs are relatively low. Once the manure is at the field, it can be applied with a tractor that pulls the dragline hose through the field or via an irrigation system. The irrigation system can be a stationary sprinkler or a single big gun sprinkler that must be moved periodically by the operator.

Liquid manure can be land applied with a dragline hose.

Other options include, a big gun sprinkler or a center pivot irrigation system that move automatically through the field. The center pivot irrigation system is usually too expensive to own just for liquid manure distribution; it is usually part of an irrigation system that also pumps clean water. The stationary and big gun sprinklers are inexpensive and easy to use.

Authors: Ray Massey, University of Missouri and Josh Payne, Oklahoma State University