Crop water requirement in irrigation engineering is characterized by delta (the total depth of water applied over a crop's growth period), base period (the duration over which that water is supplied), and duty (the irrigated area that a unit volume/rate of water can serve), with duty related to delta and base period through a proportional relationship (duty is directly related to base period and inversely related to delta). Field water requirements are computed from net irrigation requirement (crop water need minus effective rainfall) and adjusted by transit, application, and conveyance efficiencies (canal, watercourse, field) to determine gross duty and discharge, while additional factors such as field capacity, permanent wilting point, and available moisture depletion govern how much water a soil can store and how frequently irrigation must be applied. This belongs to the domain of irrigation engineering / agricultural water management within civil engineering, relating hydrology and soil-moisture theory to canal and irrigation system design.
Crop water requirement in irrigation engineering is characterized by delta (the total depth of water applied over a crop's growth period), base period (the duration over which that water is supplied)…