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Interpretation Guidelines and Links

Manure is a fact of life on any animal production operation. It is also a valuable resource that provides nutrients for crop production. Analysis of manure that is used as fertilizer provides an accurate accounting of the nutrients within the manure and allows for more accurate use and application. The evaluation of the manure prior to application also allows for reduced chances of improper use and less possibility of environmental mishap.

Submitting a manure sample for analysis is the first step in ensuring proper manure application rates. Understanding the results however, can be challenging. Below are some definitions of items included on a manure analysis report.

Sample Identification Information:


Assigned by the client. This is the farm or business where the manure sample was collected.

Description (Desc:)

Also provided by the client. This is a description of the manure that was collected.

Submitter / Account

This basic account information reflects the account the sample was submitted under and the primary name on the account.

Copies to

A list of customers receiving copies of the report other than the main account holder.

Lab ID

This is a unique identifier for the sample assigned when it is received at the lab. This number will be useful if you need to contact the lab about a specific sample.


Provided by the client. This is the date the manure sample was collected.

Arrived / Completed / Reported

These dates provide information on when the sample arrived at CVAS for testing, was complete in our system and the date reported to the client.

Primary Results and Nutrients:

Solids / Moisture, %

On arrival, manure samples will be dried in a 105C oven to determine the percent of solids and moisture in the sample. Access to results on a dry matter basis is beneficial for comparing different manure samples.

Total Nitrogen, %

Total Nitrogen is a measure of both the inorganic and organic nitrogen contained within a  sample. The amount of organic and inorganic nitrogen can vary from year to year depending on the type of manure and the storage facility. Total Nitrogen does not represent plant available nitrogen, nor does it represent any nitrogen losses due to denitrification, volatilization or leaching after application.

Ammonium Nitrogen (NH4-N) or Inorganic Nitrogen, %

Ammonium Nitrogen (also known as Inorganic Nitrogen) is the portion of nitrogen that is soluble in soil and water and therefore available to the plant for immediate use. Inorganic Nitrogen however is susceptible to volatilization as ammonia if not incorporated into the soil right away.

Organic Nitrogen, %

Organic Nitrogen can be calculated by subtracting the Ammonia Nitrogen from the Total Nitrogen. This type of Nitrogen becomes available to the plant over time as it decomposes.

Phosphate Equivalent (P2O5), %

The Phosphate Equivalent is the amount of phosphorus in the manure sample reported on a fertilizer basis. Phosphorus is available to crops once the plant converts it to phosphate.

Potassium Equivalent (K2O), %

The Potassium Equivalent (also referred to as Potassium Oxide or Potash) is the amount of in manure reported on a fertilizer basis. Approximately 90% of Potassium Oxide is available to crops the first year of application.

Secondary and Micro-nutrients:

Calcium (Ca), %

Calcium assists crops in cell nutrition, uptake of other nutrients and to better handle environmental and disease stressors.

Magnesium (Mg), %

Magnesium is important to plant photosynthesis and assists in the movement of phosphorus throughout the plant. For legume crops, magnesium helps nodules to fix nitrogen.

Sodium (Na), %

Although it is not essential for growth or yield, sodium can be harmful at high levels.

Phosphorus (P), %

Phosphorus is an important nutrient for proper plant development. It assists in seed germination, root development, and nitrogen absorption.

Potassium (K), %

Potassium plays many important roles in crop development including growth, longevity, disease resistance and over-wintering in perennial crops. It is especially important in the growth of legumes as legumes grown on low potassium fields are unable to fix nitrogen as well as those grown on fields with adequate amounts.

Sulfur (S), %

Sulfur is beneficial in increasing yield response, especially in corn crops that are not limited in nitrogen.

Chloride (Cl), %

Chloride will be used by cops in small quantities and aids in metabolism, photosynthesis, osmosis and ionic balance within the cell.

Copper (Cu), mg/kg

Copper is important in the diets of all animals with the exception of sheep. For sheep, even low levels of copper can be toxic. Manure samples from livestock facilities that utilize a copper foot bath may have elevated levels of this mineral.

Manganese (Mn), mg/kg

Manganese increases the availability of phosphorus and calcium in crops. It also improves seed germination and reduces time to harvest.

Iron (Fe), mg/kg

Iron assists in nitrogen fixing in legumes.

Zinc (Zn), mg/kg

Zinc is important in root development of crops. When soil phosphorus levels are high, zinc may be unavailable for use.

Boron, mg/kg

Boron is important in reducing nutritional disorders in crops. It is easily leached from soils so may be necessary to apply annually.

Optional Analysis:

Density, lbs. / gallon and lbs. / ft3

Density is used to determine the application rates of your manure sample based on the fertilizer needs of the soil.

Volatile Solids, % Wet-basis

Volatile Solids is the portion of solids that are lost during the heating of a liquid manure or slurry sample. It is a measure of the organic matter content of the sample. Total solids contain ash and volatile solids.

Ash, % Wet-basis

Ash is the difference between the solids and the volatile solids in the sample. Ash represents the inorganic content of the manure sample.

Water Soluble Phosphorus

Water Soluble Phosphorus is the amount of phosphorus in a manure sample that is readily dissolved in water. The ratio of Water Soluble Phosphorous: Total Phosphorous can be used as an index of the potential of phosphorus run off from manure application.