Irrigation, salinity and palm nutrition
Quick answer
FAO states the date palm is more salt tolerant than any other fruit crop, surviving in soils containing 3% soluble salts, and that above 6% it will not grow. That tolerance is real but finite, it belongs to the date palm and not automatically to ornamental palm species, and it does not remove the need for drainage and leaching.
FAO's documented salinity thresholds for date palm
| Effect on yield | ECe | Leaching requirement |
|---|---|---|
| 0% yield decrease | 5.3 mmhos/cm | 7% |
| 10% yield decrease | 8 mmhos/cm | 11% |
Two things are worth noticing. First, these figures are stated with a leaching requirement attached — tolerance is conditional on water moving salts down past the root zone. Second, the ECe at which a date palm shows no yield loss (5.3) is above the general threshold at which a soil is classed as saline (4 dS/m at 25°C), which is what FAO's claim about relative tolerance means in practice.
Why leaching, not tolerance, is the working principle
Salts are leached below the root zone by water, and that only happens if the water has somewhere to go. Any salinity management therefore begins with drainage, not with a product or with reliance on a species' tolerance.
FAO also notes that where irrigation water contains dissolved salts, drip irrigation is particularly suitable because less water is applied to the soil than with surface methods — though drip and sprinkler are technically more complicated and sediments may clog emitters.
The water is the input that matters
In an irrigated planting, the water is a renewing source of salts: whatever it carries accumulates season after season. That makes an irrigation-water analysis at least as important as a soil test — and it is the analysis most often skipped.
Boron deserves specific mention. FAO records boron toxicity arising where irrigation water is rich in boron, above 1–2 ppm, and its date palm manual notes boron deficiency was probably responsible for the death of some date palms. Both directions matter, which is exactly why boron should never be applied on assumption.
In Kuwait's conditions
FAO lists an occasional excess of soluble salts, adsorbed sodium and boron among the problems of arid-region soils. Winter rain is a natural leaching opportunity, provided drainage is ready beforehand rather than after.
Evidence limitation: irrigation-water salinity (ECw) is a different measure from soil salinity (ECe) with its own thresholds, and we have read no source giving them — so we state none. And FAO's date palm salinity figures should not be assumed to apply to ornamental palm species.
Common mistakes
- Relying on the date palm's salt tolerance while ignoring drainage.
- Applying FAO's date palm thresholds to an ornamental palm species.
- Feeding a salt-stressed palm — fertiliser is salt.
- Never analysing the irrigation water.
- Adding boron because a palm is declining.
Boundary and safety
No leaching volume, gypsum quantity or amendment rate is given here — those depend on your measured ECe, your drainage and the product, and need a site assessment. FAO's 7% and 11% leaching requirements are stated as published figures accompanying specific ECe values for date palm, not as an instruction.
Fertilisation does not treat or prevent Red Palm Weevil.
Related glossary terms
Sources
- FAO — Date Palm Cultivation, Chapter VI, including Table 39. fao.org
- FAO — Soils Portal: Salt-affected soils.
- FAO — Fertilizer and Plant Nutrition Bulletin 16, Chapters 3 and 4.
- FAO — Irrigation Water Management Training Manual No. 5.
All accessed 27 August 2026. Last reviewed: 27 August 2026.