S.D. Codified Laws § 61-1-45
If the services performed during one-half or more of any period by an individual for the person employing the individual constitute employment, all the services of the individual for the period are deemed to be employment; but if the services performed during more than one-half of any such pay period by an individual for the person employing the individual does not constitute employment, then none of the services of the individual for the period are deemed to be employment. As used in this section, the term, pay period, means the period of not more than thirty-one consecutive days for which a payment of remuneration is ordinarily made to the individual by the person employing the individual.
This section is not applicable with respect to services performed in a pay period by an individual for the person employing the individual where any of the service is excepted by § 61-1-32.
SDCL 61-1-45