After the appraisers have, pursuant to § 41-18-20, fixed the valuation of each lot and tract, the county, through its board of county commissioners, may sell the lots and tracts or any portion of the lots and tracts for not less than the appraised value. No lot or tract may be sold by the board based on any appraisal made more than one year before the date of sale.
SDCL 41-18-21