Oil palm fertiliser rates by age, and the four costliest mistakes
The right rate at the wrong time is still wasted. The order and the spread matter as much as the amount.
Fertiliser is the biggest outlay on a bearing oil palm plantation, usually more than half the year's upkeep. So the question is rarely whether to fertilise, and almost always how much, when, and where to spread it. All three decide the outcome, and the third is the one most often ignored.
The rate follows the age, then the ground
The age of the palms sets the range, and the condition of the ground decides where inside that range you land. Peat, sand and heavy mineral soil hold nutrients in very different ways, and a plantation that was over or under last year does not start from the same place as the one next door.
A genuinely accurate recommendation comes from leaf and soil analysis, sampled block by block and repeated periodically. Until you have that, the general ranges below are a place to start, not a place to stop.
The figures below are the general ranges used across many smallholdings, not a recommendation for your ground. Do not copy them wholesale without looking at the state of the plantation, its fertiliser history, and whatever symptoms are there.
The general ranges by age
A first-year immature palm (TBM 1) usually takes 0.5 to 1 kg of urea per palm per year, split across three or four applications, plus a little phosphate and potassium. The amount is small because the crown and the roots are still small, but the applications are frequent because young roots cannot take it all at once.
TBM 2 and TBM 3 climb gradually, generally to around 1.5 to 2.5 kg of urea or ammonium sulphate per palm per year, with the potassium rising faster than the nitrogen. These are the years most often cut when money is short, and also the years that most decide the first harvest.
A bearing palm (TM) has the largest potassium demand, because potassium leaves the plantation inside the bunches. The ranges commonly used: 2 to 3 kg of urea or ammonium sulphate, 1 to 2 kg of phosphate, 2 to 3.5 kg of MOP, and 0.75 to 1.5 kg of kieserite per palm per year. Borate goes on sparingly, usually 50 to 150 grams per palm, and only where the symptoms are actually there.
When to spread
The two safest windows are the start of the rains, when the soil is damp but not yet saturated, and the end of the rains before it dries out. Spreading at the peak of the wet season loses part of it to runoff; spreading at the peak of the dry season means the granules never dissolve at all.
Urea and MOP are better not spread at the same time and on the same spot as kieserite. Leave two or three weeks between them. It is a small habit that costs nothing at all and is often enough the difference between fertiliser that gets used and fertiliser that goes into the air.
Where to spread it
The most actively absorbing roots are not at the trunk base. They are in the ring of soil as wide as the crown, the circle around the palm, and that ring widens as the palm ages. Heaping fertiliser against the trunk puts it exactly where the active roots are fewest, and burns the trunk base as well if the dose is large.
Clear the weeds off the circle out to the edge of the crown, before any fertiliser leaves the sack.
Make sure no standing water is left from the last rain.
Spread it evenly right round the circle, from about a metre out from the trunk to the edge of the crown.
On a young palm the ring is narrower, following the width of its crown.
Write down the date, the type and the amount per block, in a book or in a note on your phone.
The four costliest mistakes
First, spreading onto a circle still full of weeds. Weeds take it up faster than the palm does, and most of the dose goes into a plant you did not put there. It is the most common mistake and the easiest to avoid.
Second, raising the dose to deal with yellowing fronds without checking the water first. Roots sitting under water take up nothing at all, however much goes on, and it looks very like a nutrient shortage. The difference is in how it is spread through the plantation, not in the colour of the leaf: poor drainage is often read as a lack of fertiliser.
Third, stopping fertiliser through TBM 2 and TBM 3 because nothing is coming in yet. That saving is collected back four to six years later, as smaller bunches for the life of the plantation, and it cannot be caught up by fertilising harder afterwards.
Fourth, not writing it down. Without a record of dates and amounts per block, there is no way to know whether this year's symptoms have anything to do with last year's fertilising, and every diagnosis after that becomes a guess.
What you can send us
Whatever fertiliser history you have for the last year, even if it is only a note on your phone, plus the age of the palms, the size of the plot, the soil type, and photos of the lower fronds and of the whole palm. If one block looks different from the others, say which.
From there it is usually clear whether the problem is the amount, the timing, the spread, or in fact not fertiliser at all. How a consultation works and what it costs is on its own page, and a quick question is free.