drain layers
type: Concept
preferred label: لایه زهکشی @fa
related: subsurface drainage

drain pipes
type: Concept
preferred label: لوله زهکشی @fa
related: subsurface drainage

drain ploughs
type: Concept
preferred label: خیش زهکشی @fa
related: subsurface drainage

subsurface drainage
type: Concept
alternative label: drainage, subsurface
broader: drainage
preferred label: زهکشی زیرسطحی @fa
related: drain layers
related: drain laying
related: drain ploughs
related: drain pipes

drainage
type: Concept
narrower: subsurface drainage
preferred label: زهکشی @fa

drain laying
type: Concept
preferred label: نصب زهکش @fa
related: subsurface drainage