Agriculture
Irrigation Calculator
Calculate net crop water, gross applied volume, cubic meters, and irrigation duration. The field-and-water-path visual separates useful root-zone water from modeled application loss.
Net crop water requirement (L)-
Gross applied volume (L)-
Required watering duration (hours)-
Gross applied volume (m3)-
Decision view
Root-zone water and application-loss path
Root-zone water and application-loss pathNet crop water is grossed up for application loss and translated into runtime using the entered flow.
Exact scenario comparisonTarget net water depth (mm) changes while all other entered assumptions remain constant.
| Target net water depth (mm) | Net crop water requirement (L) | Gross applied volume (L) | Required watering duration (hours) | Gross applied volume (m3) |
|---|
How to use Irrigation Calculator
- Base target depth on crop stage, soil storage, weather, and recent effective rainfall.
- Measure actual zone flow under operating pressure.
- Split runtime into cycles when soil intake or slope would otherwise cause runoff.
Calculator guide
Understanding Irrigation Calculator
One millimeter of water over one square meter equals one liter. That identity converts a crop-depth target into net liters; application efficiency and flow then determine gross water and runtime.
Calculation method
How the calculation works
Use one liter per square meter per millimeter of depth, adjust for application efficiency, and divide by flow for watering time. Multiply area by target millimeters for net liters, divide by efficiency expressed as a decimal for gross liters, and divide by liters per minute and 60 for hours.
Field practice
Turn one runtime into a workable irrigation set
Hydraulic runtime is only the first scheduling decision.
Worked situations
Practical examples
- 2,500 m² at 18 mm requires 45,000 net liters.
- At 78% efficiency, gross application is about 57,692 liters or 57.69 m³.
- At 180 L/min, modeled runtime is about 5.34 hours.
Better inputs
Useful tips
- Catch-can test distribution uniformity rather than relying only on nominal nozzle flow.
- Use separate calculations for zones with different crops, soils, or emitters.
- Recheck flow after filter, pressure, or nozzle changes.
Before relying on the result
Limitations and common mistakes
- Efficiency is one entered average and does not model distribution uniformity.
- Evapotranspiration, rainfall, soil moisture, runoff, deep percolation, wind, and legal restrictions are excluded.
- Flow is assumed constant throughout the run.
Reference
Key terms
- Net depth
- Water depth intended to reach the crop root zone.
- Application efficiency
- Share of gross applied water modeled as useful net water.
- Gross volume
- Water that must leave the system before modeled losses.
- Runtime
- Gross liters divided by measured zone flow.
Important note
Calculated from the entered field and production values. Confirm seed-lot data, equipment calibration, labels, local conditions, and applicable agronomic guidance.
Frequently asked questions
Why does 1 mm over 1 m² equal 1 liter?
A 0.001 m layer over 1 m² is 0.001 m³, which equals one liter.
Does lower efficiency increase runtime?
Yes. More gross water is required to deliver the same modeled net depth.
Can the result be split across zones?
Yes, but calculate each zone using its own area, flow, and efficiency.
Does the result prevent runoff?
No. Cycle length must respect soil intake, slope, and emitter rate.