If the services performed by any employee for an employer during more than one-half of any pay period (within the meaning of section
3306
(d)) taken into account with respect to any year constitute agricultural labor (within the meaning of section
3306
(k)), the term “unemployment insurance wages” means, with respect to the remuneration paid by the employer to such employee for such year, an amount equal to so much of such remuneration as constitutes “wages” within the meaning of section
3121
(a), except that the contribution and benefit base for each calendar year shall be deemed to be $6,000.