Decision guides · Citrus (Nagpur mandarin)
Weather and irrigation: how the five-day forecast changes the watering schedule
The weather decides how much water a tree uses: sun, temperature, wind, dry air. So adjust the watering schedule a little every week from the forecast. Rain coming: postpone. Hot dry wind coming: shorten the interval. The weekly message carries the next days' forecast.
Last checked (AI-assisted): 15 Oct 2026. Checked on 15 Oct 2026 against published ICAR, state agricultural university and FAO guidance with AI assistance. Not yet reviewed by an agronomist or tested with farmers. No spray, pesticide, fertiliser or irrigation amount is given here; for those, test your soil and ask your KVK or an agronomist.
How weather relates to water
Science measures a crop's water demand as 'reference evapotranspiration' (ET0), computed from the weather by the FAO-56 method. More sun, heat, wind and drier air mean a higher ET0, so more water for the tree.
In Vidarbha ET0 peaks in April and May and is lowest in December and January, so one schedule cannot serve the whole year.
Four decisions from the forecast
Rain coming (good rain within 2 to 3 days): postpone irrigation; after the rain, check soil moisture and decide the next one.
Hot dry wind or a heat wave: shorten the irrigation interval; no gaps while fruit is filling.
Cloudy cool days: lower demand; the interval can stretch a little.
A 10 to 15 day dry spell in the monsoon: check soil in the orchard; irrigate only if moisture has run out.
Where the forecast comes from
The IMD district forecast and agromet advisory come twice a week. VarshaKrishi's weekly message carries the next 5 days' forecast. Forecasts can be wrong, so confirm the decision with the soil.
Rainwater and drainage
Heavy rain means a risk of water standing around the roots. Keep channels open. After rain, remove water standing at the trunk; otherwise leaves yellow and the risk of gummosis-type disease rises.
What Decide will add
After agronomist review, Decide keeps a water balance from the weather and your soil type and gives a decision with a date: 'irrigate this week, because ...'. It is not open for citrus yet; Watch gives the weather and the changes only.
What to check in your field or orchard this week
- Did you read the 5-day forecast? Rain or heat?
- Did you postpone or bring forward this week's irrigation accordingly?
- After rain, is water standing at the trunk?
A Watch message says only what changed and what to check. It never names a product, a fertiliser or an irrigation amount.
Questions
What if the forecast is wrong?
It happens. Use the forecast for direction only and confirm with soil moisture.
Where do I get the ET0 figure?
From the IMD agromet advisory or the nearest weather station. In Decide we do that arithmetic; Watch does not.
What if the satellite forecast and the IMD forecast differ?
VarshaKrishi does not make its own forecast; the message carries a weather service's forecast with the source named. Look at both; when in doubt, check the soil.
Want a weekly message for your field?
Call us to join. Free to watch. What changed in your field or orchard, every week, with the date and the source.
Sources
- FAO Irrigation and Drainage Paper 56 (Allen et al., 1998): reference evapotranspiration from weather (Penman-Monteith, Hargreaves-Samani) · www.fao.org/4/x0490e/x0490e00.htm
- India Meteorological Department: district-level forecasts and agromet advisories (Nagpur, Amravati) · mausam.imd.gov.in/
- ICAR-CCRI Nagpur, month-by-month guidelines for citrus growers: irrigation intervals through the year · ccri.org.in/calendar-of-operations/
More guides
- Nagpur orange bahar management: ambia or mrig, when to stress, when to water
- How much water does an orange tree need? When to irrigate Nagpur orange
- Drip irrigation for orange trees: a month-by-month schedule
- Citrus fruit drop: causes, and what to check first
- Why citrus leaves turn yellow: read the pattern, find the cause, then act
- What are ambia and mrig bahar? Choosing the right one for your orchard
- Water stress: the sign on the tree, the sign in the soil, the sign from the satellite
- Nagpur orange season: when to harvest ambia and mrig fruit
- What is satellite farming? What a satellite sees in your orchard, and what it cannot
- Ambia bahar orange crop insurance in Maharashtra: what it covers, who can enrol, how to apply
- Nagpur orange planting (santra lagwad): soil, spacing, pit size, rootstock and planting time
- Nagpur orange fertiliser (santra khat vyavasthapan): what to ask your KVK before you apply
- Nagpur orange season and GI tag: when ambia and mrig bahar fruit reach the market
- How to see a satellite image of your own field for free: Copernicus Browser, NASA Worldview and ISRO Bhuvan
- NDVI full form and meaning: what NDVI is and what it tells you about an orange orchard
- Cotton in Vidarbha: what to check, and when, from sowing to picking
- Soybean in Vidarbha: what to check, and when, from sowing to harvest
- Tur (pigeonpea) in Vidarbha: what to check, and when, from sowing to harvest
- Chana (chickpea) in Vidarbha: what to check, and when, from sowing to harvest
How we compute this and what the limits are: the methods page