Hours of work

save as otherwise expressly provided in this Act, no adult agricultural worker shall be required to work for more than eight hours in any day and no adolescent or child for more than six hours in any day: Provided that nothing contained in this section shall be deemed to prohibit an agreement between the landowner and the agricultural workers for working for less than eight hours or six hours, as the case may be, on any particular day or days or on all days of employment or to affect any custom or practice prevailing in the locality under which the agricultural worker is required to work for less than eight hours or six hours, as the case may be.