(a) Whenever any landlord shall endorse, upon any written agreement made by and between his or her tenant and the employees of the tenant, his or her written consent to the terms of the agreement, then, and in that case only, the lien of the employees shall have precedence over that of the landlord.
(b) This precedence shall be only for the compensation specified in the agreement, the services therein specified having been rendered towards the production of the crop against which the landlord's lien attaches.