Rajma Water Requirement Calculator
Work out the seasonal and per-irrigation water requirement of rajma (kidney bean) (FAO-56 ETc = ET₀ × Kc, peak Kc 1.05) for your field, climate, soil and irrigation method.
Keep moisture steady — rajma's shallow roots and weak nitrogen fixation make it sensitive to both drought and waterlogging. Protect flowering and pod-fill; avoid heavy single irrigations.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Farmers and irrigation planners use the free Rajma Water Requirement Calculator to turn the FAO-56 crop coefficients for rajma (kidney bean) into a real seasonal water volume and an irrigation interval for their own field — no agronomy tables, works offline.
About Rajma Water Requirement Calculator
Rajma needs 350–500 mm and, with shallow roots and poor nodulation, is more irrigation-dependent than other pulses. This calculator uses the FAO-56 method — crop evapotranspiration ETc = ET₀ × Kc — with rajma (kidney bean)'s own crop coefficients (Kc 0.4 initial, 1.05 mid-season, 0.5 late) across a 100-day season. Pick your climate band (which sets reference ET₀), irrigation method (drip, sprinkler, pivot or surface — each with its own efficiency) and soil texture, and it returns the seasonal water need in cubic metres, the peak daily demand, the net depth per irrigation and how many days to wait between irrigations.
How to use Rajma Water Requirement Calculator
- 1Enter your field area and choose the climate band matching your season.
- 2Select your irrigation method and soil texture.
- 3Read the seasonal water volume, peak daily demand and irrigation interval, then follow the scheduling note.
Why use Rajma Water Requirement Calculator?
- ✓Uses rajma (kidney bean)'s real FAO-56 Kc curve, not a flat factor
- ✓Accounts for drip / sprinkler / pivot / surface efficiency
- ✓Gives seasonal volume, peak daily need and an irrigation interval
- ✓Free, instant and fully in-browser — works offline in the field
Frequently asked questions
How much water does rajma (kidney bean) need?+
Rajma needs 350–500 mm and, with shallow roots and poor nodulation, is more irrigation-dependent than other pulses. The exact figure depends on climate and season length; this tool sums ET₀ × Kc across the crop's 100-day growth stages for your conditions.
Why does rajma need more careful irrigation than other pulses?+
It has shallow roots and fixes little of its own nitrogen, so it can't buffer dry spells the way deep-rooted pulses do. Steady moisture through flowering and pod-fill is important.
How much water does rajma need?+
About 350–500 mm over the season, peaking at flowering and pod development. Frequent moderate irrigation beats infrequent heavy watering for this shallow-rooted bean.
What is ET₀ and Kc?+
ET₀ (reference evapotranspiration) is how fast a standard grass surface loses water in your climate. Kc (crop coefficient) scales it to a specific crop and growth stage. Crop water use ETc = ET₀ × Kc — the basis of FAO-56 irrigation scheduling.
Is this calculator free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline in the field and your data never leaves the device.
Related Agri tools
Tractor Fuel Consumption Calculator
Estimate your tractor's diesel consumption per hour from its horsepower, load and specific fuel consumption.
● LiveTractor Fuel Cost Per Acre Calculator
Convert your tractor's fuel use per hour into diesel litres and cost per acre for any field operation.
● LiveImplement Field Capacity Calculator
Calculate the effective field capacity (ha/h and acres/h) of any implement from width, speed and field efficiency.
● Live