Short answer. The main oil palm fertilisers are urea or ammonium sulphate (nitrogen), rock phosphate (phosphorus), MOP (potassium), kieserite or dolomite (magnesium) and borax (boron). Potassium and nitrogen are needed in the largest amounts. Compare products by cost per kg of nutrient, not bag price.
Each oil palm fertiliser supplies a different nutrient. Knowing what each one does helps you buy nutrients, not just bags — and avoid paying for a nutrient your soil already has.
| Fertiliser | Nutrient | Typical content | Main job in oil palm |
|---|---|---|---|
| Urea | Nitrogen | 46% N | Frond and canopy growth |
| Ammonium sulphate (SOA) | Nitrogen + sulphur | about 20.6% N | Nitrogen, plus sulphur |
| Rock phosphate (incl. CIRP) | Phosphorus | 30–34% P₂O₅ (generic grade) | Roots and energy transfer; slow release |
| TSP | Phosphorus | 45–47% P₂O₅ | Water-soluble, fast-acting P |
| Muriate of potash (MOP) | Potassium | 60% K₂O | Bunch number and weight, oil content |
| Kieserite | Magnesium + sulphur | about 26% MgO | Chlorophyll — prevents orange fronds |
| Dolomite | Magnesium + calcium | 10–18% MgO | Slower Mg; raises pH |
| Borax / borate | Boron | small doses (0.05–0.1 kg per palm) | Normal spear and new fronds |
Contents: Akvopedia (SNV and Wageningen), Table 3; urea at 46% N is also stated by MPOB. Grades vary by supplier — always read the bag label.
Urea carries 46% N — the highest of the nitrogen fertilisers in the table above. Its weakness is volatilisation: on dry, hot soil part of the nitrogen escapes as ammonia gas. MPOB notes this is why urea is used more cautiously on inland soils than on coastal and peat soils. Apply it on moist soil in the morning when rain is expected.
Ammonium sulphate adds sulphur, but carries less N, so you need roughly twice the weight. NEXGROW Ammonium Sulphate is labelled N 20.5% and S 24%.
Potassium is the nutrient removed in the largest amount — FAO estimates about 209 kg K per hectare a year at 25 t FFB/ha. Deficiency appears as irregular yellow-orange spots on older leaves that later merge. MOP (60% K₂O) is the usual source. Split it into two or three rounds a year, three or four on sandy soils and peat.
Kieserite (about 26% MgO) dissolves and works faster; dolomite or GML is slower but also raises soil pH. See orange fronds and magnesium deficiency before you buy.
Boron is needed in small amounts. Signs show on the youngest fronds: crinkled leaves, hooked leaflet tips, short new fronds and a flattened crown. The SNV and Wageningen guide puts borax at 0.05–0.1 kg per mature palm a year. Spread such small doses carefully and evenly.
Phosphorus rarely shows clear leaf symptoms in oil palm, so it is easy to neglect. MPOB notes that Christmas Island rock phosphate (CIRP) was used almost exclusively as the P source on oil palm and proved as effective as soluble P in trials, although availability and quality now vary. NEXGROW Rock Phosphate is labelled 23–30% P₂O₅.
The numbers on a compound bag are the percentages of N, P₂O₅ and K₂O. NPK 15-15-15 is balanced and easy to use, but mature oil palm usually needs far more potassium than phosphorus. MPOB’s compound recommendation for Sabah mineral soils, for example, is N 11%, P₂O₅ 6%, K₂O 22%, MgO 2% and B₂O₃ 0.5% at 8.5–9.0 kg per palm a year. Pick a grade whose ratio is close to your field’s needs.
The F-series are compound formulations developed by MPOB and commercialised with fertiliser companies. MPOB F3, for example, is described as a balanced mix of nitrogen, phosphate, potassium, magnesium and borate with a zeolite conditioner, formulated for palms on mineral soils and commercialised with FGV Fertilizer. The NPK grades of the F-series formulations were not published in the sources we checked, so read the bag label and the maker’s leaflet before comparing. Agros Empire does not sell F-series fertilisers.
Organic and bio-organic fertilisers add organic matter and microbes that improve soil structure and nutrient uptake. On producing palms they do not replace the potassium and nitrogen bunches remove, but they help applied nutrients stay in the root zone. See the NEXGROW bio-organic programme for oil palm.
Cost per kg of nutrient = bag price ÷ (bag weight × nutrient %)
A 50 kg bag of urea (46% N) supplies 23 kg N; a 50 kg bag of ammonium sulphate (20.5% N) supplies about 10 kg N.
Then ask whether your soil is actually short of that nutrient. For rates and schedules, go back to the oil palm fertilizer guide.
Nitrogen (urea, ammonium sulphate), phosphorus (rock phosphate, TSP), potassium (MOP), magnesium (kieserite, dolomite) and boron (borax), either as straights or in a compound NPK.
It is easy to use, but mature palms usually need much more potassium than phosphorus. A potassium-heavy compound or straights matched to soil analysis usually fits better.
Kieserite corrects magnesium deficiency faster; dolomite is slower but also raises pH. Choose on soil pH, how severe the deficiency is, and cost per kg of MgO.
An MPOB compound formulation for palms on mineral soils, containing nitrogen, phosphate, potassium, magnesium and borate with zeolite. Check the bag label for its grade.
Related guides: Oil palm fertilizer rates and schedule · Young oil palm · NEXGROW 555 guide · Oil palm programme
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