An initiated ordinance may not be proposed which would nullify such ordinances or resolutions as may be necessary for the immediate preservation of the public peace, health, or safety or for the support of any government or existing public institutions, or which would nullify the purpose for which bonds have been sold by a county pursuant to statutory authority, unless proposed within a period of thirty days after the first publication of the advertisement of the notice of sale of such bonds.
SDCL 7-18A-10