Start / Water and irrigation / Crop water demand
How much water the crop uses in each stage of the cycle, based on ET₀ and the Kc coefficient.
Pre-sizing and estimating tool: the results do not replace a design, calculation, or report signed by a qualified professional, nor verification against the applicable standards.
Water consumed in each stage of the cycle, in millimeters.
Day-by-day water demand, according to the Kc of each phase.
Drag the controls to simulate data different from what you entered (from 30% less to 30% more) and watch the result change instantly.
Approximate Kc values by FAO-56 stage, to compare with those you entered. Cultivar, climate and management change these numbers.
The calculation done in steps, with the values you entered.
The calculation memo gathers this page's inputs, results, equations, assumptions, and references, with fields for project, responsible person, and review. The full report also includes the charts and interpretations, in color. In the print window, choose Save as PDF.
Enter the average ET₀ for the period and, for each of the four crop phases, the duration in days and the Kc coefficient. The calculator adds up the crop evapotranspiration (ETc) for the whole cycle.
Average ET₀ of 5.0 mm/day and a cycle of 130 days: initial 25 days with Kc 0.40; development 35 days with Kc 0.80; mid-season 45 days with Kc 1.15; late 25 days with Kc 0.70.
Initial ETc = 0.40 × 5.0 × 25 = 50 mm; development = 0.80 × 5.0 × 35 = 140 mm; mid-season = 1.15 × 5.0 × 45 = 258.75 mm; late = 0.70 × 5.0 × 25 = 87.5 mm.
Total = 536 mm over the cycle, or about 4.1 mm per day.
From FAO-56 tables, by crop and phase. Values calibrated for your region and cultivar are more accurate.
No. ETc is the demand; irrigation is the demand minus effective rain, divided by system efficiency.
Important notice: the Agrocalcs tools make estimates and preliminary sizing based on the data entered and on published engineering methods. They do not replace a design, a calculation report or a report signed by a qualified professional (CREA/ART), nor verification against the applicable technical standards and legislation, such as the Regulatory Standards of the Ministry of Labor. Material and fuel properties vary: check with the manufacturer or with analyses of your process before deciding. By using the site, you agree to the Terms of Use.
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