Manure Testing - Is it really worth the mess?

Table of Contents

1. What are the manure sampling requirements under the Nutrient Management Regulations?
2. How do I take a manure sample?
   • Liquid Manure
   • Solid Manure

What are the manure sampling requirements under the Nutrient Management Regulations?

Section 91(3) states that a farm requiring a nutrient management plan has the option to have its’ manure tested by an accredited lab or can use the default values found in the nutrient management protocol. The default values in the protocol are the same values used in the NMAN software database. Although a producer is never required to take a manure sample in the preparation of a nutrient management plan; it is clear from the chart in the previous article Manure Testing - What is my manure really worth? that there is significant economic value in manure. Knowing the exact nutrient values of a farm’s manure allows for a more accurate nutrient management plan, and ultimately saves you money.

How do I take a manure sample?

For liquid manure, follow these steps:

1. Agitate manure storage thoroughly.

2. Collect random sub-samples of manure from various depths in the storage.

3. The sampling should take place while the storage is being emptied (i.e. every 10 loads or every 30-60 minutes from a drag hose pump).

4. Use a clean plastic pail to collect samples.

5. Mix 10-20 sub-samples thoroughly in a larger pail and transfer a small sample to a plastic jar (supplied by laboratory). Fill jar only half-full to allow room for gas build-up. Store in a cool place until sending the sample to the lab.

6. Consider taking another sample when applying to a different field to document the analysis for each field.

7. When results from the manure analysis are received, keep records and adjust any additional nutrient applications to the field.

To take a solid manure sample, follow these steps:

1. Solid manure is more difficult to sample because there is no agitation process, resulting in variations within solid storages. For this reason, it is recommended that samples be separated by the field the manure is applied to rather than by storage.

2. Samples of solid manure can be taken from the spreaders during application or from the top, middle and bottom of the storage.

3. On clean concrete or a plywood surface, take sub-samples (a forkful) of manure from several different loads throughout the application or from the different areas of storage.

4. Chop and mix the sub-samples together using a fork or shovel.

5. Divide the larger sample into four equal parts and discard three.

6. Continue to mix and subdivide until you have a sample that will fit into a plastic bag or sample jar.

7. Place sample jar into a plastic bag and ship to lab as per liquid sample.

8. Repeat sampling procedure if a portion of the manure will be applied to a different field or if the dry matter content is significantly different (dry vs "soupy"). Each storage system (or areas within the same storage with different dry matter contents) should have its own sample taken to reflect dry matter and specific nutrient content.

Manure samples should be stored in a cool place until they are shipped to a laboratory. Shipping a sample so that it arrives at the laboratory on a week day is recommended to ensure immediate processing. Sending samples through the post office is not recommended.

Knowing the analysis of manure from an operation and adjusting fertilizer rates accordingly can pay big dividends. Keeping track of the analysis over a series of years will help develop an average of the nutrients generated on the farm. Having up-to-date soil samples for the fields manure is applied to, is another key piece of the manure puzzle. With these tools, the manure application rates can be accurately determined and the maximum value of the manure can be realized.