Each person owning or operating any fertilizer factory shall pay a license tax as follows: In which the capital invested does not exceed $25,000, $50; in which the capital invested exceeds $25,000 and does not exceed $50,000, $100; in which the capital invested exceeds $50,000 and does not exceed $100,000, $200; in which the capital invested exceeds $100,000, $250 for each factory. Each fertilizer mixing plant shall pay a license tax of $15.
Ala. Code § 40-12-100 (1975)