§ 600. Fiscal year; county budget; tax levy. The fiscal year of the county shall begin on the first day of January and end with the thirty-first day of December in each year. Except as otherwise expressly provided in the alternative form adopted by the county, or the modification or change of any such form, all provisions of article seven of the county law, as now in force or hereafter amended, shall continue to apply to the county. When the county budget shall have been finally adopted, the board of supervisors shall levy the annual tax in the manner provided by law.