Ala. Code § 16-8-21
If an agreement under Section 16-8-20 is not reached within 30 days after the annexation, wherever such annexation occurs in any county having a population of less than 400,000 according to the last or any succeeding federal census, or within three years after the annexation, if such annexation occurs in a county having a population of 400,000 or more according to the last or any succeeding federal census, it shall then be mandatory to refer the final disposition of the matter to arbitration by a board consisting of three members, one to be selected by the county board of education, one to be selected by the city board of education and the third member to be selected by these two members. If the two said members are unable to agree upon the third member of the Board of Arbitration, the State Superintendent of Education shall appoint the third member.
Ala. Code § 16-8-21 (1975)