Sustainable Agriculture

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Tipsheet: Manure in Organic 

Production Systems

Benefits of Manure

Livestock manure is a valuable resource for organic and sustainable soil management. It is most effectively used in combination with other sustainable practices such as crop rotation, cover cropping, green manuring, and liming. In organic 

production, manure is commonly applied to the field as raw manure (fresh or dried) or composted manure (Kuepper, 

2003). Manure can add important plant nutrients (nitrogen, potassium, and phosphorus, collectively known as NPK) to the 

soil and improve soil quality. Composting raw manure by adding other feedstocks and bedding will aid decomposition 

and produce a humus-rich finished product with little to no ammonium or soluble nitrate. This finished product will build 

soil fertility (Evanylo et al., 2008). The timing of manure application is very important to ensure that the manure benefits 

the plants and soil. Manure, if applied and managed correctly, can be a great means of enhancing soil and crop quality, 

but there are some important aspects of soil health and food safety to consider when using it in an organic farm system.

USDA Organic Regulations for Manures and Manure-Based Compost 7 CFR § 

205.203(c)

The NOP has very specific guidelines about manure-composting procedures. 

y Raw manure must not contaminate soil, water, or crops with pathogens, excess nutrients, etc. Manure should 

not be applied on frozen ground.

y Raw animal manure must be composted unless it is:

 Applied to land used for a crop not intended for human consumption; 

 Incorporated into the soil not less than 120 days prior to the harvest of a product whose edible portion has 

direct contact with the soil surface or soil particles; or 

 Incorporated into the soil not less than 90 days prior to the harvest of a product whose edible portion does 

not have direct contact with the soil surface or soil particles.

y For composted manures, an initial C:N ratio of between 25:1 and 

40:1 must exist for the blend of materials. The NOP Guidance 

Document 5021: Compost and Vermicompost in Organic Crop 

Production provides alternative methods and recommendations: www.ams.usda.gov/NOPProgramHandbook 

y Temperatures between 131° F and 170° F must be sustained for 

three days using an in-vessel or static aerated pile system.

y Temperatures between 131° F and 170° F must be sustained 

for 15 days using a windrow composting system, during which 

period the materials must be turned a minimum of five times, 

and this period must be followed by an adequate curing period.

Considerations

y Organic producers making their own compost must keep accurate records of their composting operations to demonstrate 

that the compost was produced according to the criteria cited 

above. 

Sheep manure in a cover cropped walnut alley. This 

farmer stopped grazing sheep in their walnut orchard 

due to the potential risk (and liability) of contamination 

by pathogens from undecomposed manure contacting 

walnuts during harvest. Photo: Rex Dufour, NCAT
Page 2 Tipsheet: Manure in Organic Production Systems

y Compost that contains no animal materials as feedstock may be used without restriction provided that it contains no prohibited or restricted-use plant materials. 

y If the composted manure is purchased, the grower needs documentation from the supplier showing that the 

compost process meets NOP requirements or else must undertake further composting on-site that meets NOP 

requirements. 

y Manure left unincorporated for even a couple of days can lose a significant part of its nitrogen content through 

volatilization. 

y Fresh manure can possibly transmit human disease (salmonella/E.coli), so fresh manure should not be used as a 

side-dress fertilizer on vegetable crops, and there are specific parameters on intervals between manure application and harvesting crops.

y Continual manure use tends to acidify soil. As manure breaks down, it releases various organic acids that assist 

in making soil minerals available. Over time, this process depletes the soil of calcium and causes pH levels to fall 

below the optimum for most crops. Manures do supply some calcium, but not enough to counterbalance the 

tendency toward increased acidity.

y Use of raw manures can sometimes increase weed problems. Some manure contains weed seed from bedding 

materials like straw and old hay. This problem can be eliminated if using composted manure. 

y Fresh manure with high levels of nitrogen and salts can burn seedling roots. Manure should be tested before 

applying to soil. 

y Heavy applications of raw manure can cause increased salinity in soils that do not drain well. 

y Manure is rich in specific nutrients like phosphate and potash. These nutrients can benefit crops, but repeated 

applications can result in a detrimental buildup in the soil. Specifically, there has been a concern with an oversupply of phosphorus in soils where too much broiler litter or dairy manure is used. Excessive phosphate in the 

soil can interfere with plant uptake of other nutrients, such as copper and zinc. Excessive potash can restrict 

boron, manganese, and magnesium uptake (Kuepper, 2003). 

NOP Recordkeeping Requirements

Accurate records of manure and compost application and production must be kept by all farmers using these types of 

soil amendments. Farmers must accurately record the application date of any untreated or composted soil amendment 

of animal origin. If the amendment came from a third-party source, documentation is required that the amendment has 

undergone a scientifically valid process to meet requirements for a treated amendment, and that it has been stored in 

a manner that prevents contamination of surrounding areas and water supplies. 

NOP Manure Storage and Handling Requirements

y NOP requires farmers to handle and store biological soil amendments of animal origin in a way that does not 

contaminate covered produce; food-contact surfaces; areas used for growing, harvesting, holding, and packing; 

and water sources and distribution systems. Farmers must also make sure that treated amendments are not contaminated by untreated or “in-process” amendments.

y FDA does not allow the use of human waste for growing produce, except for sewage sludge bio-solids that are 

used according to Environmental Protection Agency requirements (FDA, 2015). Sewage sludge is prohibited 

under the USDA organic regulations at section 205.105(g). 

y Manure can be stored if it is under the cover of a building or a tarp and away from any drainage areas and standing water. 

Raw Manure vs. Composted Manure

y An effective composting process converts animal wastes, bedding, and other raw products into humus—the 

relatively stable, nutrient-rich, and chemically active organic fraction found in fertile soil. In stable humus, there 

is practically no free ammonia or soluble nitrate, but nitrogen is tied up as proteins, amino acids, and other biological components. Other nutrients are stabilized in compost as well (Kuepper 2003). 

y Composting livestock manure reduces many of the drawbacks associated with raw manure use. It’s also less likely 

to cause nutrient imbalances. The composted manure can safely be applied directly to growing vegetable crops. 
www.attra.ncat.org Page 3

y Raw manure can be an excellent and effective source of available nitrogen and other nutrients, and can stimulate biological processes in the soil if the application is timed correctly, and if it is applied in the correct manner 

(refer to above considerations and NOP 5021 recommendations). 

Manure Application and Rates

y Tilling manure into the soil shortly after spreading or applying it on cover crops are two safe application methods that conserve manure nutrients. Grass cover crops, such as rye and ryegrass, are especially good as “catch 

crops”—cover crops grown to absorb soluble nutrients from the soil profile to prevent them from leaching. 

y Sheet composting, a process where a thin layer of slowly decomposing organic matter is applied on top of 

the soil and then tilled in, improves the capture of ammonia nitrogen from manure, but requires tillage, which 

leaves the soil bare and vulnerable to erosion and leaching losses. Surface application of manure (with no soilincorporation) eliminates most leaching and erosion losses but increases ammonia losses to the atmosphere.

y A combination of soil testing and nutrient budgeting for NPK levels is recommended when using manures, as 

nutrient levels can fluctuate based on many factors, and the timing of manure application is crucial to optimize 

nutrient uptake and minimize leaching. More information about nutrient budgeting can be found in ATTRA’s publication Nutrient Management Plan (590) for Organic Systems.

y The best time to apply manure, for the strongest effect, is just before 

planting. Applications too far in advance of planting risk nitrogen loss 

through leaching if rainfall is significant. Plowing or incorporating the 

manure into the soil is one method to use so that nutrient loss is minimal.

y It is important to monitor soil fertility regularly when using manure, to 

avoid manure-induced soil imbalances as described above.

y Typically, manure is applied before the most nitrogen-demanding 

crop in the rotation and after the amount of plant-available nitrogen 

during the year of application has been estimated. Nitrogen availability of manure varies greatly, depending on the type of animal, type 

and amount of bedding, and age and storage of manure. Manure 

should not be the sole nitrogen source in an organic system. Excess 

levels of soil phosphorus (P) can result from continual manure applications. Where P buildup is a concern, legumes should be included in the 

rotation in place of manures to provide additional nitrogen (Eghball and 

Power, 1999).

Food Safety Modernization Act (FSMA) Proposed Regulations for Manure Use 

The Food Safety Modernization Act (FSMA) requires the Food and Drug Administration (FDA) to develop regulations 

aimed at improving the safety of produce. The process of developing these regulations is currently underway. It is good 

for producers to sign up for updates related to the new rules from organizations they trust. The FDA website contains 

up-to-date information about the proposed FSMA regulations: www.fda.gov/Food/GuidanceRegulation/FSMA/. 

New food-safety standards may address such topics as the following: 

y Methods for preventing contamination of produce from exposure to pathogens potentially present in biological 

soil amendments of animal origin 

y New standards for using manures and compost 

References 

USDA Organic Regulations 7 CFR 205

www.ams.usda.gov/nop

USDA National Organic Program Handbook

 www.ams.usda.gov/NOPProgramHandbook

Figure 1. This graph predicts N release during the first year after manure application. 

Source: Adapted from Bary et al., 2000.
Page 4 Tipsheet: Manure in Organic Production Systems

The following guidelines and policy memos contain additional information related to manure use in organic 

systems and can be found in the NOP handbook: 

NOP 5006: Processed Animal Manure in Organic Crop Production

NOP 5016: Allowance of Green Waste in Organic Production Systems

NOP 5021: Compost and Vermicompost in Organic Crop Production 

NOP 5025: Commingling and Contamination: Prevention in Organic Production and Handling

NOP 2602: Recordkeeping of Certified Operations

NOP 2615: Organic System Plans, Updates and Notification of Changes

PM 11-4: Evaluation of Materials Used in Organic Crop, Livestock and Handling Operations

USDA National List of Allowed and Prohibited Substances www.ams.usda.gov/NOPNationalList

US Food and Drug Administration. 2015. Food Safety Modernization Act. 

www.fda.gov/Food/GuidanceRegulation/FSMA/

Bary, A., C. Cogger, and D.M. Sullivan. 2000. Fertilizing with Manure. Washington State University Cooperative Extension, Pullman, WA.

Dufour, Rex, Sarah Brown, and Denise Troxell. 2014.Nutrient Management Plan (590) for Organic Systems: Western 

State Implementation Guide. NCAT/ATTRA Publication. 

https://attra.ncat.org/attra-pub/summaries/summary.php?pub=465

Eghball, B. and J. Power. 1999. Composted and Non-Composted Manure Application to Conventional and No-Tillage 

Systems: Corn Yield and Nitrogen Uptake. American Society of Agronomy. www.prairieswine.com/pdf/3588.pdf

EPA. 2012. Nutrient Management and Fertilizer. www.epa.gov/agriculture/tfer.html

Evanylo, G., C. Sherony, J. Spargo, D. Starner, M. Brosius, and K. Haering. 2008. Soil and water environmental effects of 

fertilizer-, manure-, and compost-based fertility practices in an organic vegetable cropping system. Agriculture, Ecosystems & Environment. Vol. 127, No. 1. p. 50–58. 

Kuepper, George. 2003. Manures for Organic Crop Production. NCAT/ATTRA Publication 

https://attra.ncat.org/attra-pub/summaries/summary.php?pub=182

Rosen, C.J. and B.M. Bierman. 2005. Using Manure and Compost as Nutrient Sources for Fruit and Vegetable Crops. 

University of Minnesota Extension, Minneapolis, MN. www.extension.umn.edu/distribution/horticulture/M1192.html

Wander, M. 2009. Managing manure fertilizers in organic systems. University of Illinois. 

www.extension.org/article/18628 

Further Resources

Using Manure as Fertilizer for Vegetable Crops 

www.soils.umn.edu/academics/classes/soil3416/veg_manure.htm

Manure Management Plan: A step-by-step guide for Minnesota Feedlot Operators 

www.pca.state.mn.us/publications/wq-f8-09.pdf

Produced by the National Center for Appropriate Technology

www.ncat.org • 1-800-275-6228 (1-800-ASK-NCAT)

(Parent organization to the ATTRA Project, www.attra.ncat.org)

Tipsheet: Manure in Organic Production Systems

By Thea Rittenhouse, NCAT Agriculture Specialist

Published July 2015

This product was developed with support from

U.S. Department of Agriculture’s Agricultural Marketing Service, National Organic Program