In Wisconsin, a testing laboratory must participate in the Manure Analysis Proficiency Program as a condition to be certified by the Wisconsin Department of Agriculture, Trade, and Consumer Protection (WDATCP) if results are to used in nutrient management planning or related to any government cost sharing program. A certified testing laboratory must interpret and report the nutrients available according to Table 3 on page 13 of the Wisconsin Conservation Planning Technical Note.
Below is a listing of the manure test and approved analytical procedure used by Dairyland Laboratories:
|Liquid||Entire sample is homogenized using a high-speed blender. The resulting slurry is sub-sampled and analyzed without drying.|
|Semi-Solid and Solid||
A scissor clipping is utilized for the bedding material followed by homogenization of the entire sample with an industrial strength food processor. The resulting mixture is sub-sampled for analysis without drying.
|Moisture||Loss of weight by heating for 16 hours at 100°C.|
|Nitrogen (N)||Direct combustion with detection by thermal conductivity.|
|Phosphorus (P)||Extract in pressurized microwave vessel with 50% nitric acid solution, measure with an ICP.|
|Potassium (K)||Extract in pressurized microwave vessel with 50% nitric acid solution, measure with an ICP.|
|Organic Matter (OM)||Loss of weight by ignition at 600°C.|
|Ammonia||Distillation with magnesium oxide into Kjelsorb reagent followed by back titration with dilute sulfuric acid.|
|Nitrate Nitrogen||Extract with nitrate interference suppressor and analyzed by ion specific electrode (ISE).|
|Complete Mineral Package (P, K, S, Ca, Mg, Zn, Cu, Mn, Fe, Na, B)||Extract in pressurized microwave vessel with 50% nitric acid solution, measure with an ICP.|
|All other Micro-Nutrients||Extract in pressurized microwave vessel with 50% nitric acid solution, measure with an ICP.|