Being a vital part of the labor force, tenant-farmers on private agricultural lands primarily devoted to rice and corn under a system of share crop or lease tenancy whether classified as landed estate or not shall be deemed owner of a portion constituting a family-size farm of five (5) hectares if not irrigated and three
(3) hectares if irrigated.
In all cases, the land owner may retain an area of not more than seven (7) hectares if such landowner is cultivating such area or will now cultivate it.