Effective on the next term of office, the Judge of Probate of Madison County shall be paid an annual salary equal to not less than 70 percent of the combined state and county compensation paid to circuit judges of Madison County. The salary prescribed herein shall be paid from the county general fund on warrants processed in the usual manner, and, when such salary becomes effective, shall constitute the total compensation paid to the judge of probate, in lieu of any and all other salary, expense allowance, or compensation heretofore provided by law.