Agriculture
Irrigation Input Rate Calculator
Convert root-zone moisture deficit, allowable depletion, field area, application efficiency, and system flow into net depth, gross volume, and runtime.
Root-zone refill plan
Convert a measured soil-water deficit into application depth, volume, and pump runtime
The model keeps net crop need separate from field losses and checks the refill against the selected management-allowed depletion.Soil-water profile
Root-zone storage, refill target, and application loss
The blue band is current storage, the hatched gap is the net refill, and the amber cap is water lost before reaching the root zone.Detailed calculation process
Use volumetric water-content difference to size the refill
General symbolic formulas
Dnet = Z × max(θFC − θ, 0)Dgross = Dnet / ηVnet = 10 A DnetVgross = Vnet / ηt = 1000 Vgross / (3600 q)Dtrigger = Z θFC ADOne millimetre over one hectare equals 10 m³. Efficiency increases pumped depth; it does not change the crop-root deficit.
Symbols and units
Worked substitution with current inputs
Application ledger
| Stage | Depth | Volume | Meaning |
|---|
Use steps
- Measure water content in the active root zone.
- Use a field-specific field-capacity value.
- Enter delivered flow and measured efficiency.
Examples
Drip block: use the wetted crop area, not the entire property.
Rain adjustment: rerun after effective rainfall changes measured water content.
Limitations
This planning balance excludes infiltration limits, runoff, salinity leaching, crop-stage stress, rainfall forecasts, pressure variation, and legal allocation constraints.
Irrigation-rate FAQ
Why is gross depth larger?
Some pumped water is lost before it becomes root-zone storage.
Can gravimetric moisture be entered?
No. Convert it to volumetric water content using bulk density first.
Is runtime continuous?
It is hydraulic time; split sets may be needed to respect infiltration and equipment limits.