Take ammonium tests when sampling manure
September 10, 2012 by Natalie Rector Michigan State University Extension
September 10, 2012 – The best time to take manure samples is as you are hauling out the storage systems. Manure that is going to the field is the most representative of the nutrients per 1,000 gallons or per ton. Any agitation or mixing will have occurred and taking a manure sample at hauling time will help build a base line of nutrients applied per acre.
You won’t get the results back in time for this year’s application rates, but you will have them for future reference, to gauge consistency over time and to build credibility. It is easy to get busy hauling and forget to pull a sample – don’t forget this fall!
Fill a plastic bottle, leaving a little empty space, clean it off and put it in the freezer. Mail it by overnight delivery. If the manure storage has a lot of variability from liquid to solids, taking several samples over the various consistencies will also be helpful in gauging not only future application rates but also the fertilizer value back to the crop next season.
Most importantly, be sure to ask for not only the total nitrogen content in the manure, but also the Ammonium-N value as well. Often, this is a little more expensive but what is another $10 for a test when a 5,000-gallon tank of manure is worth about $200 in nutrients?
A list of manure testing labs can be found on Michigan State University’s Environmental Quality website.