The following words and terms, when used in this chapter, have the following meanings, unless the context clearly indicates otherwise:
Act-The Pennsylvania Fertilizer, Soil Conditioner and Plant Growth Substance Law (3 P. S. § § 68.1-68.23).
Primary plant nutrient-A fertilizer component consisting of nitrogen, phosphorus and potassium compounds.
Secondary plant nutrient-A fertilizer nutrient component other than primary plant nutrients.
7 Pa. Code § 73.1