In real life, the mechanical weeders are only used in organic agriculture where pesticides are not allowed. the tine based weeders are used in cereals crops where the tines pull up/damage broad leafed weeds whilst leaving the cereal crop relatively undamaged, in row crops, the spaces in between the crop rows are cultivated with a hoe to kill the weeds.
Conventional agriculture would use a combination of pre-emergence sprays with residual activity to prevent the growth of weeds and post emergent sprays with contact activity to kill existing weeds.
