Why have ducks and geese been used to control weeds in cotton and mint crops?

Geese have been utilized as a form of biological control to manage weed populations in cotton fields and mint plantations.12

This practice is categorized as a mechanical or grazing method of weed management. By grazing on unwanted vegetation, these birds help reduce weed competition for the primary crops. However, this approach has notable limitations, including the logistical costs associated with maintaining livestock or fowl for agricultural purposes. While biological grazing is often considered more ecologically desirable than chemical alternatives, it remains a specialized method that is not as widely applied as traditional tillage.21