As in all analytical evaluations, the greatest variability and potential occurrence of error is in the sampling process. This certainly applies to manure analysis due to the tremendous variation that can occur within storage structures and over time.
The sample should be representative of the entire material sampled. This may require multiple samples if the consistency of the manure varies significantly within the storage unit. Often the best and most convenient time to collect a manure sample is when the manure is being removed from the storage unit and spread.
Collect small amounts of manure in a clean bucket from many places within the manure storage unit or sample periodically as the storage unit is emptied. This large composite sample should then be thoroughly mixed and a small sub-sample sent to the lab for analysis. Below are basic sampling guidelines and several references that provide significantly more detail concerning proper sampling techniques.
- Liquid storage units must be agitated before sampling.
- Solid manure samples should include both manure and bedding.
- Fill the sample bottle leaving approximately 1/2 inch of air space.
- Be sure the sample bottle is closed securely.
- Label the bottle and fill out the sample information form complete.
- Forward to CVAS as quickly as possible. Avoid shipping over the weekend, preferably shipping as early in the week as possible.
The table below indicated the amount of sample needed for manure testing.
*To run these tests, please include the additional sample volume listed for dry or liquid manure samples.
References
Recommended Methods of Manure Analysis
Manure Sampling for Nutrient Management Planning, Agronomy Facts 69
http://extension.psu.edu/cmeg/facts/agronomy-facts-69