As used in this part, unless the context otherwise requires:
Available Phosphoric Acid (P205) percent
Soluble Potash (K20) percent
Total Nitrogen (N) percent
Available Phosphorus (P) percent
Soluble Potassium (K) percent
provided, that the effective date of the regulation shall not be less than six (6) months following the issuance of the regulation; and provided further, that for a period of two (2) years following the effective date of the regulation, the equivalent of phosphorus and potassium may also be shown in the form of phosphoric acid and potash. After the effective date of a regulation issued under this subdivision (9)(B), requiring that phosphorus and potassium be shown in the elemental form, the guaranteed analysis for nitrogen, phosphorus, and potassium shall constitute the grade;