(a) The City Commission of Florence, Alabama, shall waive city taxes on annexed farm property, so that the residential dwelling on the property and one acre of land shall be taxed at the regular city tax rates, but the remainder of the land used as farm and agricultural property shall be exempt from city taxes.
(b) If and when the land is sold for, or is used for, non-agricultural purposes, then city taxes for the three years preceding the sale shall be assessed against the property to be paid by the purchasers, or by the owner in the case of change in use of the property.