Free tools · Free, no sign-up
Orange orchard water-use calculator
An estimate of how much water a Nagpur orange (mandarin) tree uses on an average day of the month, from the FAO-56 crop coefficient and ten years of weather near your town.
Estimated water use
– litres per tree per day
- litres per tree per week
- –
- hours of drip per day
- –
- cubic metres per acre per day
- –
- trees per acre
- –
How this is worked out
- Reference evapotranspiration (ET0)
- –
- Crop coefficient (Kc)
- –
- Orchard water use (ETc = Kc × ET0)
- –
- Ground per tree
- –
- Watering efficiency
- –
Status: the citrus crop coefficients are from FAO-56 tables and are pending review by a citrus agronomist (CCRI or PDKV). This is an estimate of water use, not a watering prescription. Check with your KVK or agronomist before changing your watering.
Before you use this number
- It is an average day for the month. Hot, windy days use more water; cloudy, humid days use less.
- Rain is not counted. After good rain the soil holds water and the trees need less, sometimes none for days.
- If you are resting the trees for ambia or mrig bahar (holding back water to bring on flowering), this number does not apply during the rest. Follow your agronomist.
- Soil type and root depth are not used. Sandy soil needs smaller, more frequent watering; heavy soil holds more.
Sources
- Crop coefficient: Allen et al. (1998), FAO Irrigation and Drainage Paper 56, Table 12 (citrus, no ground cover), Table 17 (basal Kcb), Table 20 (wetted fraction) and Eq. 75 (wetted, exposed soil).
- Canopy from greenness: Carlson and Ripley (1997), fractional vegetation cover from NDVI, simplified to a straight line between 0.15 (bare) and 0.80 (full canopy).
- ET0: FAO-56 Penman-Monteith, computed by VarshaKrishi for every day of 2016 to 2025 from NASA POWER daily weather (NASA Langley Research Center POWER Project). power.larc.nasa.gov
- Watering efficiency: Brouwer, Prins and Heibloem (1989), FAO Irrigation Water Management Training Manual No. 4: surface 60 %, sprinkler 75 %, drip 90 %.
- The same Kc rules as the VarshaKrishi advisory engine; the calculator is checked against it on 293 cases.
These data were obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program.
Want a message like this about your field every week?
VarshaKrishi reads the satellite pixels inside your own field boundary, every week, and sends one short message in Marathi, Hindi or English.