Kelly Nichols, Agriculture Agent, Montgomery County | kellyn@umd.edu
Mark Townsend, Agriculture Agent Associate, Frederick County | mtownsen@umd.edu
University of Maryland Extension
The best time to take a manure sample is when you are loading the spreader. Just like soil sampling, the goal is to take a representative sample. Liquid pits should be agitated before sampling. If bedding is used, ensure that the sample you take includes a similar amount of bedding that is in the barn. Speaking of bedding, if gypsum is used, be careful of toxic hydrogen sulfide gas that can be released during agitation.
Each type of manure (as defined by type of livestock and/or liquid vs. solid) should have its own sample. Each sample should have 10-15 collection points, or subsamples. These can be taken from different loads as the tanks or spreaders are filled. Put all samples in a clean container that is labeled with the name of the type of manure.
A list of labs in the region who do manure testing can be found on our website. Check the lab’s website for the submission form and fill it out completely. Mail the sample early in the week so it is not sitting in a mailroom over the weekend. If the sample will not be mailed right away, they can be stored in a freezer. For nutrient management plans, manure samples are valid for two years.
