AY-277-W
Did you know that livestock excrete 70-80 percent of the nitrogen, 60-85 percent of the phosphorus, and 80-90 percent of the potassium fed to them? For example, if you feed 100 acres of corn to your livestock and collect all of the manure, there may be enough phosphorus and potassium to fertilize 75 acres (depending on your soil test phosphorus and potassium levels). Although the availability of manure nitrogen depends on several uncontrollable factors, the availability of manure phosphorus and potassium do not. Most of the fertilizer value of manure comes from phosphorus and potassium, not nitrogen. This bulletin will help you begin to manage manure as a crop nutrient resource, not a waste product.
The first step in treating animal manure as a crop fertilizer is to determine its nutrient content. Once the manure nutrient content has been established, you can calculate the proper application rate based on your management objectives, crop yield potential, and soil test values for the field(s) that will receive manure.
A spreader load of manure with an unknown nutrient content is like an unmarked bag or sprayer tank of fertilizer. You must first determine the nutrient content before the proper application rate can be calculated. Unlike inorganic fertilizer, manure is not a uniform product. This makes obtaining a representative manure sample very important.
Taking a manure sample at the time of spreading increases your chances of obtaining a representative sample. Collect samples while the storage pit is being mixed. Take samples from several spreader loads while emptying the pit and mix them together to form one composite sample. Do not enter a pit to collect the manure sample. Dangerous gases are present near the pit surface.
If the pit is not mixed prior to loading the spreader, consider collecting separate composite samples while the pit is being emptied. Record the depth (top third, middle third, bottom third, etc.) where the samples were taken for future reference. In pits that are not mixed, manure solids, which contain most of the phosphorus, tend to settle to the bottom.
For solid manure (daily scrape and haul, manure stack, etc.) take samples from several spreader loads and combine to form one composite sample for analysis. If you apply manure throughout the year, you may want to take samples several times during the year to see if the manure nutrient content changes.
To prepare a manure sample for shipping, fill a plastic container (approximately one quart) 2/3 full with manure, squeeze out the air in the upper third of the container (to allow for gas expansion), and seal tightly for shipping. Ship samples early in the week to avoid having them sit over the weekend. Freezing or refrigerating the samples prior to shipping helps preserve the samples during transport. Do not place manure samples in glass containers. Gas expansion creates pressure that can cause glass containers to explode. Many laboratories supply containers and/or detailed instructions on how to prepare and ship samples. Contact the laboratory for further information.
As a minimum, have manure analyzed for percent solids, total nitrogen, ammonium nitrogen (NH4+-N), phosphate (P2O5) and potash (K2O). Once a baseline of manure nutrient information has been established, you probably only need to send in one or two samples per year. Have additional samples analyzed if you make significant changes in livestock feeding, watering, or housing.
With this sampling method you may be done spreading before you receive the laboratory manure nutrient analysis report. You can still credit the nutrients in manure applied after you get the test results if you know the manure application rate.
Dry Total
matter NH4+N N P205 K20
Bedding
Species or litter (%) -- lb./ton manure--
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Swine no 18 6 10 9 3
yes 18 5 8 7 7
Beef no 151 4 11 7 10
no 522 7 21 14 23
yes 50 8 21 18 26
Dairy no 18 4 9 4 10
yes 21 5 9 4 10
Sheep no 28 5 18 11 26
yes 28 5 14 9 25
Poultry no 45 26 33 48 34
yes 75 36 56 45 34
deep pit 76 44 68 64 45
Turkey no 22 17 27 20 17
yes 29 13 20 16 13
Horse yes 46 4 14 4 14
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1 Open concrete lot
2 0pen dirt lot
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Dry Total
matter NH4+N N P205 K20
Waste
Species handling (%) ---lb./1000 gal. manure---
--------------------------------------------------
Swine liquid pit 4 26 36 27 22
lagoon1 1 3 4 2 4
Beef liquid pit 11 24 40 27 34
lagoon1 1 2 4 9 5
Dairy liquid pit 8 12 24 18 29
lagoon1 1 2.5 4 4 5
Veal calf liquid pit 3 19 24 25 51
Poultry liquid pit 13 64 80 36 96
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1 Includes lot runoff
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In addition to laboratory analysis, portable test kits can measure plant available manure nitrogen at the time of application. These manure test kits give a reasonable estimate of plant available nitrogen in approximately five minutes and can be used as a supplement to the laboratory analysis. If you apply manure based on nitrogen, you can use the test kit results to calculate manure nitrogen application rates. The laboratory analysis can then be used to determine phosphate and potash credits, as well as fine-tune nitrogen credits. Contact your local cooperative Extension office about the availability of manure test kits in your area.
Mineralization
Manure type Manure handling factor
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Swine Fresh 0.50
Anaerobic liquid 0.35
Aerobic liquid 0.30
Beef Solid without bedding 0.35
Solid with bedding 0.25
Anaerobic liquid 0.30
Aerobic liquid 0.25
Dairy Solid without bedding 0.35
Solid with bedding 0.25
Anaerobic liquid 0.30
Aerobic liquid 0.25
Sheep Solid 0.25
Poultry Deep pit 0.45
Solid with litter 0.30
Solid without litter 0.35
Horse Solid with bedding 0.20
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* Source: MWPS-18 (Midwest Planning Service) Livestock Waste Facilities Handbook
Enter your manure analysis values in the table below. Use the worksheet to estimate the plant available nitrogen (PAN) in the manure. Manure type is the species and form (solid or liquid). If you have liquid manure your values should be in lb./1 000 gal. If you have solid manure your values should be in lb./ton. Tables 1 and 2 provide average nutrient values for various animal species and manure storage systems. These tables show how storage structure and livestock species can affect the nutrient content of manure, but the table values are not meant as a replacement for your laboratory manure nutrient analysis.
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Manure Dry Total Ammonium N
Type Matter N (NH4+-N) PAN P2O5 K20
% -------------------lb./1000 gal.or ton-------------------
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Practically all of the phosphate (P2O5) and potash (K2O) applied in manure is available to the crop the first year. Use your P2O5 and K2O values from the laboratory manure nutrient analysis for all calculations requiring phosphate and potash.
1. The amount of nitrogen available the first year (or plant available nitrogen, PAN) is a combination of all the ammonium-nitrogen (NH4+-N) plus that portion of the organic nitrogen that will mineralize and become available to the crop during the growing season.
To calculate PAN, start by subtracting the NH4+-N value from the Total Nitrogen value as follows.
Formula: Total N - NH4+-N = Organic N
Your values: _____ - _____ Organic N*
2. The amount of organic nitrogen that will mineralize during the first year is the organic N calculated in step 1 multiplied by a mineralization factor. Refer to Table 3 to obtain the mineralization factor that matches your livestock operation.
Formula: Organic N (from step 1) x Mineralization Factor = Organic N Available First Year
Your values: _____ Organic N (lb./1000 gal. or lb./ton) x _____ =
_____ Organic N available first year (lb./1000 gal. or lb./ton)
3. Finally, to calculate PAN, add the ammonium-nitrogen (NH4+-N) obtained in your manure analysis to the organic N available the first year, from step 2.
Formula: NH4+-N + Organic Available First Year = PAN (lb. /1000 gal. or lb./ton)
Your values: ______ (lb./1000 gal. or lb./ton) + _____ (lb. /1000 gal. or lb/ton)
= ______ PAN (lb./1000 gal. or lb./ton)
Write your PAN value in the manure analysis table at the top of the page.
* lb./1000 gal. for liquid manure; lb./ton for solid manure
Whether you want to match manure application rates with the nutrient requirements of a certain crop and yield goal or always apply a specific rate of manure, you need to calibrate your spreader. This is a simple process requiring a few measurements and calculations. The following instructions apply to the worksheets that follow; you can use them to calculate application rates for your liquid or solid manure spreader.
Start by determining the amount of manure your spreader holds. The owner's manual should provide information on the size or capacity of your spreader. If you do not have this information, AY-278 "Estimating Manure Spreader Capacity," explains how to calculate the capacity of both liquid and solid manure spreaders. Enter your spreader capacity in the space provided at step 1 in the appropriate worksheet.
Next (step 2) estimate the nutrient content of a full manure spreader. If you assign a dollar value for each nutrient, you can get a rough estimate of the economic value of a spreader load of manure. This information can help determine the distance you can afford to haul the manure.
In step 3, calculate the actual manure application rate in tons or thousands of gallons per acre. For this step you need to know the width of spread and the distance traveled to empty the spreader.
The final step (step 4) is to determine the pounds of manure nutrients applied per acre. This is simply the manure nutrient content (from the laboratory analysis table) multiplied by the manure application rate (step 3). You can make spreader adjustments or change tractor speed to modify the manure application rate to match crop nutrient needs.
Obtaining a uniform manure application can be a challenge, especially with solid manure spreaders. Adjusting tractor speed and overlapping the outside edges helps to apply solid manure evenly. Incorporating surface applied manure also distributes the manure and minimizes nitrogen volatilization. When injecting manure, keep the knives clear and unplugged.
The amount of PAN (plant available nitrogen) that will actually be available to your crop is affected by application method and timing relative to crop growth. Uncontrollable environmental factors, like temperature and rainfall, also influence the availability of nitrogen. Nitrogen can be lost by leaching below the crop root zone and as a gas through a process called denitrification. The uncertain availability of manure nitrogen has led many producers to ignore the potential nutrient credits from manure applications.
Application method or time does not significantly influence phosphorus and potassium availability, making these nutrients available to crops as they are applied. Phosphate and potash attach to soil particles and generally move very little in soil; however, these nutrients can be lost with eroded soil in runoff. Preventing soil erosion helps retain all crop nutrients and protect surface water quality.
Table 4 lists short-term nitrogen-loss estimates based on the method of manure application. Generally, the availability of manure nitrogen decreases as the time between manure application and crop nitrogen uptake increases. Most of the potentially available manure nitrogen may be lost from summer or early fall applications (before soil temperature at a depth of four inches drops below 50 F), particularly with surface applied manure.
A relatively new product, the pre-sidedress nitrate soil test, can help in determining the need for additional nitrogen fertilizer in fields that have received manure. The test is most useful when manure has been broadcast (whether incorporated or not) or in fields with a long history of manure applications. Your local cooperative Extension office has information about the pre-sidedress nitrate test. Note: manure applications based on nitrogen alone usually result in excess phosphorus and potassium In the soil. Test soils regularly to avoid excessive phosphorus and potassium build-up.
Application Type of Nitrogen lost
method waste (%)
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Broadcast solid 15-30
liquid 10-25
Broadcast solid 1-5
with immediate liquid 1-5
cultivation
Knifing liquid 0-2
Sprinkler liquid 15-35
irrigation
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* Source: MWPS-18 (Midwest Planning Service) Livestock Waste
Facilities Handbook
1.Spreader Factor: Liquid manure spreaders must divide spreader capacity by 1000.
Formula:
Value from Spreader Capacity AY-278: _____ gallons / 1000 = Liquid Spreader Factor
Your values:
Value from Spreader Capacity AY-278: _____ gallons / 1000 = _____ Liquid Spreader Factor
Formula:
Plant Available Manure Nutrients x Liquid Spreader Factor (listed above)
= Nutrients per Spreader Load
Your values: (from Laboratory Analysis table)
_____ lb. N (PAN) per 1000 gal.x _____ (Liquid Spreader Factor) = _____ lb. PAN per load
_____ lb. P205 per 1000 gal. x _____ (Liquid Spreader Factor) = _____ lb. P205 per load
_____ lb. K20 per 1000 gal. x _____ (Liquid Spreader Factor) = _____ lb. K2O per load
Formula:
Liquid Spreader Factor x 43.560 ft.2/acre = Thousand gal. manure applied / acre
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Width of Spread (ft.) x Distance Traveled (ft)
Your values:
x 43,560 ft.2/acre = ______ Thousand gal. manure applied / acre
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______ width (ft.) x ____ distance (ft.)
4.Manure Nutrient Application Rate: The manure nutrient application rate is simply the manure nutrients per 1000 gallons multiplied by the manure application rate from step 3.
Formula:
Nutrient lb. per 1000 gal. x Thousand gal applied/acre = Nutrient lb./acre
Your values:
_____ N (PAN) lb. per 1000 gal. x _____ thousand gal. applied / acre = _____ lb. / acre
----- P2O5 lb. per 1000 gal. x _____ thousand gal. applied / acre = _____ lb. / acre
_____ K2O lb. per 1000 gal. x _____ thousand gal. applied / acre = _____ lb. / acre
Your value (from owner's manual or Spreader Capacity AY-278): _________ tons of manure
Formula:
Plant Available Manure Nutrients x Spreader Capacity = Nutrients per Spreader Load
Your values: (from Laboratory Analysis table, page 3)
_____ lb. N (PAN) per ton x _____ tons = _____ lb. PAN per load
_____ lb. P2O5 per ton x _____ tons = _____ lb. P2O5 per load
_____ lb. K2O per ton x _____ tons = _____ lb. K2O per load
Formula:
Spreader Capacity (tons) x 43,560 ft.2/acre = Tons manure applied/acre
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Width of Spread (ft.) x Distance Traveled (ft.)
Your values:
tons x 43.560 ft.2 /acre = ______ Tons manure applied / acre
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____ width (ft.) x ____ distance (ft.)
4.Manure Nutrient Application Rate: The manure nutrient application rate is simply the manure nutrients per spreader load multiplied by the manure application rate from step 3.
Formula:
Nutrient lb. per ton x ____ Tons applied / acre = ______ Nutrient lb. / acre
Your values:
_____ N (PAN) lb. per ton x _____ tons applied / acre = ______ lb. / acre
_____ P2O5 lb. per ton x _____ tons applied / acre = ______ lb. / acre
----- K20 lb. per ton x _____ tons applied / acre = ______ lb. / acre
New 8/93
Editor: Cheri Janssen, Department of Agronomy
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University, and U.S. Department of Agriculture cooperating; H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperative Extension Service of Purdue University is an affirmative action/equal opportunity institution.