If the salary of any officer or employee whose salary or compensation was fixed before the effective date of this act by the provisions of article 8 of chapter 28 of the Kansas Statutes Annotated, or acts amendatory thereof or supplemental thereto, has been reduced during the calendar year 1972 as a result of a change in population of the county, the board of county commissioners of such county shall reimburse such officer or employee for such loss of salary until otherwise provided by law.