A board of county commissioners may not adopt zoning regulations under this part that require minimum lot sizes in an area zoned for residential use unless:
(1) the zoning regulation requiring minimum lot sizes is applied to land that is within 3 miles of the limits of an incorporated municipality; or
(2) the county has adopted a land use map in its growth policy pursuant to 76-1-601 (5) that sets forth projected population densities and recommended minimum lot sizes.