Start / Water and irrigation / Crop water demand
In how many days the soil reaches stress and how much to irrigate each time.
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.
How much soil water has dropped since field capacity, in mm, with the average balance.
How long the soil can last without irrigation, for each level of effective rainfall.
Drag the controls to simulate data different from what you entered (from 30% less to 30% more) and watch the result change instantly.
How many days the readily available water in your soil lasts for combinations of ET₀ and effective rainfall, with the Kc and soil you entered.
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 soil data, the ET₀ and Kc of the current phase, and the average effective rain. The calculator estimates how many days the readily available water lasts and the gross depth of each irrigation.
CC of 30%, PMP of 12%, roots at 60 cm, p of 0,5, ET₀ of 5.0 mm/day, Kc of 1,0, effective rain of 1.0 mm/day and efficiency of 85%.
AD = (30 − 12) ÷ 100 × 600 = 108 mm; AFD = 0.5 × 108 = 54 mm. Balance = 1.0 × 5.0 − 1.0 = 4.0 mm/day.
Days to stress = 54 ÷ 4.0 = 13.5 days. Depth per irrigation = 54 ÷ 0.85 = 63.5 mm gross.
When the deficit reaches the readily available water (AFD). Before that, the plant normally does not lose yield from lack of water.
Because rainfall is irregular and the balance uses averages. To decide the irrigation interval, use the daily balance with data from the nearest weather station.
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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