If the board of trustees at any time shall transfer and irrevocably appropriate to the debt service fund maintained by it for the payment of bonds issued pursuant to § 34-10-16 moneys received from sources other than tax levies pursuant to § 34-10-21, it may in its discretion cause the amount so transferred to be certified to the county auditor, who shall thereupon reduce the levy to be spread upon the tax lists for collection in the following year by the amount so certified, or by much lesser amount as shall be directed by the board of trustees.
SDCL 34-10-22