Manure and Compost: Nitrogen Availability in Organic Production

ANR-34
Agriculture and Natural Resources
Date: 
05/30/2016
Alan Sundermeier, Associate Professor and Extension Educator, Agriculture and Natural Resources, Wood County

Manure and compost are important sources of nitrogen for organic producers. Determining the actual amount of nitrogen available for plant use is a challenging obstacle for producers. A nutrient management plan needs to consider the following factors when determining nitrogen recommendations for crop needs.

Source Influence of Manure and Compost

Manure and compost nitrogen content and availability can vary greatly between species of animals that produced the manure. Table 1 compares the nitrogen content availability for different poultry. Poultry manure typically has the highest nitrogen content. Laboratory analysis is recommended to determine actual nitrogen content of the source material.

Table 1. Actual Analysis of Inputs Measured at OSU Hirzel Organic Grain Research Site
Nitrogen Source
Analysis total N
Moisture
Total N lbs/ton
Typical rate per acre
Total N per acre
Straw pack beef manure
0.96 %
73 %
19.1
4 ton
76.4 lb
Leaf, cannery, horse, duck compost
0.8 %
36 %
16.0
4 ton
64.0 lb
Leaf, cannery, horse, duck compost
0.89 %
32 %
17.8
4 ton
71.2 lb
Leaf, cannery, horse, duck compost
1.01 %
51 %
20.2
4 ton
80.8 lb
Poultry compost
1.75 %
24 %
35.0
2 ton
70.0 lb
Poultry compost
2.01 %
20 %
40.2
2 ton
80.4 lb
Poultry compost
2.5 %
35 %
50.0
2 ton
100.0 lb
Poultry compost
4.0 %
 
80.0
2 ton
160.0 lb

Bedding or Additives

In the case of manure, the amount and type of bedding added to the manure will influence the nitrogen content and availability. In the same manner, the type of additives used to create the compost will influence compost nitrogen content. Components such as leaves, corn stalks, straw, wood chips or other organic materials vary greatly in the amount and availability of their nitrogen content. The uniformity of the material is also important, especially in straw pack manure where animal patterns in the barn determine concentrations of raw manure. Accurate sampling with representative source materials will result in more accurate analysis.

Moisture

The amount of liquid contained in the manure or compost affects the concentration of nitrogen per ton applied. Table 2 illustrates the nitrogen differences between raw manure and manure with bedding.

Table 2. ​Estimated Nitrogen Content of Various Manures
Animal Type Raw manure >75% moisture Manure pack with bedding
N lbs/ton N lbs/ton
Dairy 5.3 – 9.8 4.2 – 6.9
Beef 7.4 – 10.6 7.9
Swine 10.4 – 12.6 6.6
Sheep 15.0 6.3
Poultry 19.2 – 21.0 52.0  dry
Horse 7.4 6.6
These values include a 25% loss factored due to storage and handling losses prior to land application.
Source: Ohio Livestock Manure Management Guide, Ohio State University Bulletin 604.

Storage and Handling Losses

As manure and compost are stored over time, nitrogen losses may occur due to exposure to the atmosphere. Producers need to account for these losses of nitrogen over time. Losses also occur when moving manure or compost before field applications. Typically a factor of 25 percent loss is used.

Application Rate

Knowing the amount of material applied per acre will help achieve intended supplies of nitrogen for the target crop. Accurate interpretation of laboratory analysis is needed to calculate the target application rate. Calibration of spreaders improves accuracy of application rates. The capacity of the spreader needs to be determined.  This can be done by weighing an average load of manure. Then the number of spreader loads per field can be calculated (Mancl, 1991). Nitrogen application rates must also consider other nutrients applied, such as phosphorus, to prevent excessive soil nutrient levels.

Volatilization Losses

Immediate incorporation or injection of manure or compost minimizes losses of ammonium nitrogen to the atmosphere. Under warm and dry soil conditions, up to 90 percent of ammonium could be lost due to volatilization without incorporation. Delaying incorporation by one day under these conditions could result in an additional 50 percent loss. Compost is a more stable material and will have less volatilization losses compared to manures. Table 3 identifies the nitrogen losses expected, based on weather conditions, incorporation timing and field moisture.

Table 3. Ammonia Nitrogen Losses from Volatilization from Manure
Incorporation Delay from Application Residue Coverage Cool Temperature Warm Temperature
Wet Soil Dry Soil Wet Soil Dry Soil
Ammonia Loss, % applied
No Incorporation Bare Soil 40 50 75 90
No Incorporation Standing Crop 20 25 40 50
1 day Bare Soil 10 15 25 50
2 day Bare Soil 13 19 31 57
3 day Bare Soil 15 22 38 65
4 day Bare Soil 17 26 44 73
Natural Resource Agriculture and Engineering Service (NRAES) 130

Plant Available Nitrogen

Not all the nitrogen applied as manure or compost is immediately available to the crop, as shown in Table 1. Residual nitrogen may be released over several years in the soil. Calculating plant available nitrogen is influenced by the source, timing of application, soil conditions and temperature. First year available organic nitrogen is estimated at 33 percent and ammonium nitrogen available first year can range from 15 to 75 percent depending on application timing.

Organic producers need to have an understanding of plant available nitrogen derived from compost or manure sources. Cereal grain crops such as corn, wheat, oats and spelt need this available nitrogen to produce grain. By compensating for potential losses, satisfactory crop yields in organic production may still be achieved.

Acknowledgements
  • Funding to support the management of the Hirzel site and the development of these materials was provided by Ohio Agricultural Research and Development Center (OARDC) Organic Food, Farming, Education and Research Program at oardc.osu.edu/offer.
  • This publication was produced in cooperation with Ohio State University’s John E. Hirzel Sustainable Agriculture Research and Education Site and the Agricultural Incubator Foundation at Bowling Green, Ohio.
  • The author dedicates this publication in memory of John Hirzel, long-time supporter of sustainable agriculture, state leader in organic grain and vegetable production, and friend.
Bibliography
  • James, R., et al. (2006). Ohio Livestock Manure Management Guide, 2006. Ohio State University Extension Bulletin 604.
  • Meisinger, J. & Jokela, W. (2000). Ammonia Volatilization from Dairy and Poultry Manure. Adapted from (NRAES-130) Natural Resource Agriculture and Engineering Service, Box 4557, Ithaca, NY. 14852. Retrieved on March 25, 2014 from dairyn.cornell.edu/pages/20cropsoil/documents/MeisingerandJokela-NRAES130-2000.pdf.
  • Mancl, K. (1991). Land Application of Waste: Spreading and Injection. Ohio State University Extension Factsheet AEX-707-91. Retrieved on March 25, 2014 from ohioline.osu.edu/aex-fact/0707.html.
  • Smith, R. (2006). Nitrogen Fertility Management in Organic Production, University of California Extension presentation. Retrieved on March 25, 2014 from cemonterey.ucanr.edu/files/85316.pdf.
  • Sullivan, D. (2008). Estimating Plant-available Nitrogen from Manure. Oregon State University Extension Bulletin EM 8954 E. Retrieved on March 25, 2014 from ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/20528/em8954-e.pdf.
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