WAC 16-200-7063. How will the department determine whether a commercial fertilizer meets Washington standards for metals?

(1) To determine whether a commercial fertilizer meets Washington standards for metals, the department will use the following formula: Pounds of product applied per acre per year X metal content of product (ppm) 1,000,000 The number used for pounds of product applied per acre per year will be the maximum application rate allowed by the commercial fertilizer label. If specific label directions for use are not available, the department will use the Washington application rates listed in subsection (2) of this section, divided by four. (2) Using normal agronomic rates that are representative of soil, crop rotation, and climatic conditions in Washington state, the department developed the following Washington application rates: Nutrient 4 Yr. Cumulative Total (lbs./acre) Nitrogen (N) 1600 Phosphorous (as P2O5) 700 Potassium (as K2O) 1600 Boron (B) 12 Calcium (Ca) 800 Chlorine (Cl) 300 Copper (Cu) 10 Iron (Fe) 80 Magnesium (Mg) 400 Manganese (Mn) 40 Molybdenum (Mo) 4 Sulfur (S) 400 Zinc (Zn) 30 Lime (CaCO3 equivalent) 20,000 Gypsum (CaSO4) 16,000 Nutrient 4 Yr. Cumulative Total (lbs./acre) Nitrogen (N) 1600 Phosphorous (as P2O5) 700 Potassium (as K2O) 1600 Boron (B) 12 Calcium (Ca) 800 Chlorine (Cl) 300 Copper (Cu) 10 Iron (Fe) 80 Magnesium (Mg) 400 Manganese (Mn) 40 Molybdenum (Mo) 4 Sulfur (S) 400 Zinc (Zn) 30 Lime (CaCO3 equivalent) 20,000 Gypsum (CaSO4) 16,000 (3) To ensure that the maximum acceptable cumulative metals additions to soil are not exceeded, the department will assume the commercial fertilizer will be applied at the maximum rate as stated on the label or established in this rule.