As oil palm growers, we want to make sure that we give the best fertilizers to our palms to get optimum growth and yield. Yet, when it comes to Phosphate fertilizers, a lot of planters and plantation owners choose the cheapest source.
Phosphate is one of the macro nutrients needed by oil palm and it is not wise to only be penny wise but pound foolish. You may think that you are reducing cost but in fact you are wasting fertilizer input, increasing cost of operation and losing opportunity cost in terms of yield loss!
Take a look at this chart below.
Let me show you how to interpret this chart correctly.
At a quick glance, you will note that TSP or Triple Super Phosphate is right on top followed by other rock phosphates in the chart. TSP is a form of water-soluble phosphate. Does this mean water-soluble phosphate is superior than all other rock phosphates? Yes and no.
First of all, you have to look at other factors such as the type of crop, soil type, fertilizer dosage, rainfall pattern and fertilizer cost. In this chart, TSP performs the best. However, the chart does not compare the cost of application. Most of the time, water soluble phosphate is more expensive than rock phosphate.
Secondly, there are three types of rock phosphates that give results that are just below TSP. This are North Carolina, Tunisia and Bayovar rock phosphates. This are categorized as High Reactive rock phosphate. In this chart, high reactive rock phosphates give results that are almost as good as TSP and they are mostly cheaper than TSP, depending on market conditions.
The other rock phosphates such as Tapira, Araxa, Huila, etc, range from low reactive to medium reactive and are sourced from different parts of the world. This rock phosphates are not commonly used in Malaysia and her neighboring countries. They can be cheap but not commercially viable if they cannot help planters to produce good oil palm yield.
If you say High Reactive rock phosphates perform the best among all rock phosphates, you are right! However, this is not all there is to it. Do you notice another important point in this chart? I will let you reflect on it for a while…
Manage to see it? I will explain further.
Low reactive rock phosphate
Do you notice that even as you put higher dosage of Tapira rock phosphate, it will not outperform Araxa, Lobatera or Huila rock phosphates in terms of yield? Rock phosphates such as Araxa and Huila are low reactive to medium reactive rock phosphates.
Likewise, medium rock phosphate such as Huila cannot outperform the result of high reactive rock phosphates such as Bayovar rock phosphate even as you increase higher dosage of Huila rock phosphate.
I consulted with Dr. Chien about this and he explained to me like this:
Theoretically, every Phosphate Rock has its maximum solubility in soils, the so-called solubility-product constant, depending on its apatite structure.
Once a low-reactive Phosphate Rock reaches its maximum solubility-constant in soil solution, it will not reach the higher P concentration in soil solution from a highly reactive PR regardless how much of the lower-reactive Phosphate Rock applied.
This explains why double or triple the amounts of low-reactive Phosphate Rock still cannot produce the same crop yield as a highly reactive Phosphate Rock applied at lower rate.
Dr. S. H. Chien
Former Principal Scientist – Soil Chemistry
International Fertilizer Development Centre (IFDC)
I bold the last sentence to emphasize a very important point that is missed by many plantation owners, purchasing committee and finance teams in large plantation companies and even agronomists.
To help you understand better, I prepare the chart below that summarizes the earlier chart and quotes from Dr. Chien.
As an oil palm planter, you have to reflect on the type of rock phosphates that you have been buying and applying into your field. The common rock phosphates available in the Malaysian market are mostly low reactive to medium reactive.
Declining yield performance in plantations that use low and medium reactive rock phosphate does not match the claim that Phosphate fertilizer is not important.
Furthermore, fertilizers have a synergistic effect on plant growth and yield. Hence, using low reactive rock phosphate will not only affect a single nutrient uptake but also other nutrients uptake. This will be covered in a future write up.
This research has already proven that Bayovar Rock Phosphate can help to increase oil palm yield by up to 2.6 mt more than medium reactive rock phosphate source.
In ringgit terms, this means you can lose as much as RM1000.00 per hectare if you continue to apply low and medium reactive rock phosphate! If you have 1000 hectares of planted oil palm area, this is equivalent to a loss of RM1 million!
Take action to stop the loss and contact us if you need more clarification.