Division of Agricultural Sciences and Natural Resources • Oklahoma State University

	 In addition to meat, livestock and poultry operations

produce another valuable commodity—manure. Manure is a

by-product containing many plant nutrients and organic matter. Animal manure can be an asset rather than a liability for

producers when effectively managed and properly used on

field crops. Besides providing valuable macro- and micronutrients to the soil, manure supplies organic matter to improve

the soil’s physical and chemical properties. It also increases

infiltrationofwaterandenhancesretentionofnutrients,reduces

wind and water erosion, and promotes growth of beneficial

organisms.

Each year in Oklahoma, an estimated 10 million tons of

waste produced by animals in confinement is available for

use as fertilizer. This translates into tens of millions of pounds

of plant nutrients and organic matter available to enrich our

soil. The key to capturing the benefits of this resource is good

nutrient management.

Nutrient Contents in Manure

	 The actual nutrient value of manure from a particular

operation will differ considerably with the method of collection,

storage facilities, and species of animal. The approximate

fertilizer nutrient content for various manures is shown in

Table 1. These are average values, and a chemical analysis

on each sample should be obtained before applying manure

to a field.

Factors Affecting Nutrient Composition 

in Manure

	 Nutrients in waste may be lost or converted to otherforms

during treatment or storage and handling, affecting their availability for use by growing plants. The type of animal housing

system and/or waste handling method is known to affect the

final nutrient composition of the waste.

	 Bedding and water have a diluting effect on the final nutrient concentration of waste and result in less nutrient value

per ton. In addition, the type of housing and waste handling

system can decrease the final nutrient composition of waste

materials. For instance, there can be considerable loss of

nitrogen (N) to the air, and there is a potential for runoff and

leeching when animal waste is exposed to weather conditions

in an open lot system. In contrast, there is considerably less

N loss from a completely covered feedlot with manure pack

or a liquid lagoon.

Table 1. Average Nutrient Analyses (as is)* of Major Types 

of Manure in Oklahoma

Manure Type	 Dry Matter	 Total N	 P2O5	 K2O	

% lbs./ton

Feedlot Manure	 62	 24	 21	 25

Broiler Litter	 77	 63	 61	 50

	 	

lbs./1000gal

Lagoon Effluent	 0.5	 4.2	 1.0	 5.0

Lagoon Sludge	 7	 15	 16	 11

Dairy Slurry	 3	 13	 11	 11

*P2O5 and K2O are commonly used for fertilizer ingredients instead

of P and K. Some laboratories may still report in elemental P and K

content. To convert, use the following equations: K2O = K x 1.2 or

P2O5 = P x 2.29

Figure 1. Land application of animal manure recycles 

nutrients back to the land. It is the most economical and 

environmentally sound method to handle by-products in 

meat and milk production.

Hailin Zhang

Waste Nutrient Management Specialist

Department of Plant and Soil Sciences

PSS-2228

Oklahoma Cooperative Extension Fact Sheets

are also available on our website at:

http://osufacts.okstate.edu

Fertilizer Nutrients 

in Animal Manure

Oklahoma Cooperative Extension Service
2228-2

Table 2. Estimated Ranges of Nitrogen Availability in 

Animal Manure.

1st Year 	 Future

Manure Type	 Availability	 Availability	

Feedlot manure	 50% - 70%	 10% - 20%

Poultry litter	 50% - 70%	 10% - 15%

Dairy manure	 50% - 70%	 10% - 20%

Swine lagoon effluent	 30% - 50%	 5% - 10%	

	 Only about 5 percent to 15 percent of the phosphorus (P)

or potassium (K) is lost with various waste handling methods,

with the exception of the open lot and lagoon systems. Up

to 80 percent of the P in waste can settle in lagoons, making

it unavailable in the liquid used for spray irrigation of cropland.

Difference Between Nutrients in Manure 

and Commercial Fertilizers

	 Plant nutrients in commercial fertilizers are mostly water

soluble and readily available for plant uptake. Not all the

nutrients in manure are available to crops during the year

of application because some are in their organic form, while

others can be lost during application.Therefore, an availability

factor (percent of nutrients available) is used for rate calculations based on the amount of nutrients available during the

first year. The N availability can vary from 30 to 80 percent

depending on the type of manure and application method.

	 Most nitrogen in lagoon effluent is in the ammonium form

and is more subject to volatilization loss during storage and

land application. The average N available in the first year of

application and in subsequent years is listed in Table 2. The

greatest response from animal manure application can be

obtained by promptly incorporating the waste into the soil

either by injection or cultivation. The practice of injecting,

chiseling, or knifing liquid animal waste beneath the soil

surface minimizes N loss to air or runoff. Therefore, use a

lower availability factor if manure is surface applied and not

incorporatedwithintwodays.Otherwise,ahigherfactor canbe

used. The time of manure application also affects the amount

of nutrient available to a crop. Higher availability is expected

when manure application matches the crop nutrient uptake.

	 The availability ofPandKin manure is considered similar

to that in commercial fertilizer since the majority of P and K

in manure is in its inorganic form. For all manure types, 90%

of P and K is considered to be available during the first year

of application and 10% for future years.

Taking Credits From Manure

	 Nutrients in animal manure are as effective as commercial fertilizers for improving crop production if used properly.

Producers should subtract the available nutrients in the manure from their regular fertilizer program so they can reduce

fertilizer cost and avoid nutrient buildup in soils. Follow these

steps to take credits from manure:

1. Test soils:Knowwhatnutrients thesoilalready contains,

including residual N, available P and K, as well as soil

pH. Take soil samples before land application. A soil test

report indicates the amount of nutrients that the soil can

supply and recommends the amount needed from other

sources.

2. Analyze manure: Take samples before spreading manure. Results should include dry matter contents as well

as N, P, and K contents.

3. Determine when to apply:Applying manure just before

planting or at peak growing stages gives plants the best

chance to use the nutrients. It also reduces the chance

of nutrient runoff.

4. Determine how much to apply: To best calculate application rates, balance the nutrient levels in the soil and

manure with the needs of the crop. This will ensure you

apply enough nutrients for your yield goal but not more

nutrients than the crop needs.

5. Calibrate manure spreader: By calibrating the equipment, you can guard against applying too much or too

little manure per acre. Too much manure may be harmful

to the water supply, and too little could hurt crop yields.

6. Use supplemental fertilizer as needed:ExtraN may be

needed if application rates are based on P. Phosphorus

and K can build up in the soil if manure is used to meet

the N needs of a crop.

7. Consider conservation measures: Maintaining grass

waterways,buffer strips,andotherwaterqualitypractices

will help prevent nutrients from reaching nearby water

supplies.

8. Review nutrient management plan frequently: As the

operation changes, so will your nutrient needs. Changes

in land use, numbers of livestock, feeding programs, and

application methods all affect the amount of nutrients

available for crop use.

Other Related Extension Publications

BAE-1734 - 	What is a Waste Management System?

BAE-1736 - 	Lagoons for Livestock Waste Treatment

BAE-1739 - 	Movement of Odors Off-Farm

BAE-1740 - 	Measuring Farmstead Odors

PSS-2207 - 	How to Get a Good Soil Sample

PSS-2225 - 	OSU Soil Test Interpretations

PSS-2236 - 	Knowing When to Fertilize

PSS-2245 - 	Using Lagoon Effluent as Fertilizer

PSS-2246 - 	Using Poultry Litter as Fertilizer

PSS-2248 - 	Sampling Animal Manure

PSS-2249 - 	Managing Phosphorus From Animal Manure

PSS-2250 - 	Using Stockpiled Feedlot Manure as Fertilizer

PSS-2251 - 	Selecting Forages for Nutrient Removal from

	 	 	 Animal Manure

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Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert E. Whitson, Director of Cooperative Extension Service, Oklahoma State University, Stillwater, Oklahoma. This publication is printed and issued by Oklahoma State University as authorized by the Vice President, Dean, and Director of

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