1. (1) Primary nutrients. A fertilizer is mislabeled if any of the following apply, based on a sample collected and tested according to s. ATCP 40.16:

   1. (a) The fertilizer contains less than 90% of the label guarantee amount for any primary nutrient.

   2. (b) The actual percentage amount of any primary nutrient falls at least 2 percentage points short of the percentage amount stated on the label.

      Note: For example, if the label states that the fertilizer contains 30% N, but testing shows that the fertilizer contains only 27.5% N, the fertilizer is mislabeled.

   3. (c) The combined nutrient index of primary nutrients actually present is less than 97% of the combined nutrient index of the amounts guaranteed, where the combined nutrient index is calculated according to sub. (3).

2. (2) Secondary and micronutrients. A fertilizer is mislabeled if, based on a sample collected and tested according to s. ATCP 40.16, the actual amount of any secondary nutrient, micronutrient or enhancing element listed in a guaranteed analysis falls short of the label guarantee by an amount that exceeds the allowable deficiency shown in Table 1.

   TABLE 1

   - See PDF for table

3. (3) Combined Nutrient Index. Combined nutrient index, for purposes of sub. (1) (c), equals {total nitrogen (N) guarantee} + {available phosphate (P²O⁵) guarantee} + {soluble potash (K²O) guarantee}.

   Note: The multipliers in sub. (3) are based on approximate relative average wholesale prices for primary plant nutrients in Wisconsin. The department will conduct periodic wholesale price surveys and will adjust the multipliers, as the department deems necessary, by rule.

4. (4) Custom mixed fertilizer. Label guarantees for a custom mixed fertilizer shall be calculated from the custom mix formulation.

History

History: CR 04-140: cr. Register September 2005 No. 597, eff. 10-1-05; CR 15-045: am. (1) (c), (3) Register March 2016 No. 723, eff. 4-1-16.