Sustainable Oil Palm Farming / Fertiliser recommendations

Download: Module 4: Fertiliser Application

Background

Fertilisers can make up 60 percent of the total costs of producing palm oil so it is important to apply fertilisers efficiently.

Different fertilisers have different concentrations of nutrients. To know how much fertiliser to apply, it is necessary to know the nutrient concentration of the fertiliser (see Table 3).

Table 3: Nutrient content of the most important fertilisers

Fertiliser	Nutrient content (%)
Nitrogen (N)
Urea	46
Ammonium nitrate (AN)	34
Sulphate of ammonium	20.6
Phosphorus (P2O5)
Triple super phosphate (TSP)	45—47
Rock phosphate (RP)	30—34
Diammonium phosphate (DAP)	46
SP-36 (Indonesia)	36
Potassium (K2O)
Muriate of potash (MOP, KCl)	60
Magnesium (MgO)
Kieserite	26
Dolomite	10—18
Langbeinite	18

General fertiliser recommendations

In Table 4 to Table 7, general recommended fertiliser application rates are shown. Recommendations depend on palm age and current yields and include:

• Mature palms on mineral soils (see Table 4) ;
• Mature palms on peat soils (see Table 5);
• Immature palms on mineral soils (see Table 6);
• Immature palms on peat soils (see Table 7) .

If you are not certain about how much fertiliser to apply, the tables below can be used as a guide. Recommended doses should give a good yield in most circumstances, but it is important to get local information and not to rely on the tables only.

Table 4: Fertiliser recommendations for mature palms (> 3 years after planting) in mineral soils, in kilo per palm per year. FFB = fresh fruit bunches

Fertiliser type	Recommendation (kilo per palm per year)
	Yield: 18—24 t/year FFB	Yield: > 24 t/year FFB
Nitrogen*
Urea	1.2 – 1.5	1.5 – 2.0
Ammonium nitrate	1.6 – 2.0	2.0 – 3.0
Sulphate of ammonium	2.4 – 3.0	3.0 – 4.0
Phosphorus**
Triple super phosphate	0.5 – 0.8	0.8 – 1.2
Rock phosphate	1.0 – 1.5	1.5 – 2.0
Diammonium phosphate	0.5 – 0.8	0.8 – 1.2
SP-36 (Indonesia)	0.6 – 1.0	1.0 – 1.5
Potassium
Muriate of potash (MOP, KCl)	1.8—2.5	2.5—3.0
Magnesium
Kieserite	0.5—1.0	1.0—1.2
Dolomite	1.0—1.5	1.5—2.0
Langbeinite	1.0—1.5	1.5—2.0
Boron
Borax	0.05—0.1	0.05—0.1

* Young mature palms (4—6 years after planting) need 50—100 percent more N than the amounts given here, to develop a large and healthy canopy.
** Tropical soils are often very poor in P so the application of extra P is beneficial.

Table 5: Fertiliser recommendations for mature palms (> 3 years after planting) in peat soils, in kilo per palm per year. FFB = fresh fruit bunches.

Fertiliser type	Recommendation (kilo per palm per year)
	Yield: 18—24 t/year FFB	Yield: > 24 t/year FFB
Nitrogen
Urea	1.2—1.5	1.5—2.0
Ammonium nitrate	1.6—2.0	2.0—3.0
Sulphate of ammonium	2.4—3.0	3.0—4.0
Phosphorus*
Rock phosphate	1.0—1.5	1.5—2.0
Potassium**
Muriate of potash (MOP, KCl)	2.5—3.0	3.0—4.0
Magnesium***
Kieserite	0—0.5	0—0.5
Dolomite	0—1.0	0—1.0
Langbeinite	0—0.8	0—0.8
Boron
Borax	0.05—0.1	0.05—0.1
Copper
Copper sulfate (CuSO4)	0.1—0.2	0.2—0.4
Zinc
Zinc sulfate (ZnSO4)	0.1—0.2	0.2—0.4

* To reduce the soil acidity it is best to apply phosphorus as rock phosphate.
** On peat, a K to N ratio of > 3 is needed, so it is best to apply three times more K₂O than N.
*** Mg application on peat is usually needed only when deficiency symptoms are observed.

Table 6: Fertiliser recommendations for immature palms (1—3 years after planting) in mineral soils, in kilo per palm per year.

Fertiliser type	Recommendation (kilo per palm per year)
	Years after planting:
	1	2	3
Nitrogen
Urea	0.6—1.0	1.3—1.7	1.3—2.2
Ammonium nitrate	0.8—1.5	1.7—2.4	1.7—2.9
Sulphate of ammonium	1.2—2.0	2.6—3.4	2.6—4.4
Phosphorus
Triple super phosphate	0.6—1.1	0.8—1.3	1.0—1.5
Rock phosphate	0.9—1.5	1.2—1.9	1.5—2.2
Diammonium phosphate	0.6—1.1	0.8—1.3	1.0—1.5
SP-36 (Indonesia)	0.8—1.4	1.0—1.6	1.3—1.8
Potassium
Muriate of potash (MOP, KCl)	0.8—1.3*	2.5—3.5**	2.5—3.5
Magnesium
Kieserite	0.7—1.1***	0.7—1.5***	0.7—1.5
Dolomite	1.4—2.1	1.4—2.8	1.4—2.8
Boron
Borax	0.05	0.10	0.10

* 0.5 kg/palm on coastal clays and K-rich volcanic soils.
** 2.0 kg/palm on coastal clays and K-rich volcanic soils.
*** No application needed on coastal clay soils.

Table 7: Fertiliser recommendations for immature palms (1—3 years after planting) in peat soils, in kilo per palm per year.

Fertiliser type	Recommendation (kilo per palm per year)
	Years after planting:
	1	2	3
Nitrogen
Urea	0.8	0.8	1.5
Ammonium nitrate	1.2	2.0	2.0
Sulphate of ammonium	1.6	1.6	3.0
Phosphorus
Rock phosphate*	1.1	1.4	1.7
Potassium
Muriate of potash (MOP, KCl)	1.6	2.5	4.0
Magnesium	Not needed	Not needed	Not needed
Boron
Borax	0.05	0.10	0.10
Copper
CuSO4	0.1—0.2	0.05—0.1	0.05—0.1
Zinc
ZnSO4	0.1—0.2	0.05—0.1	0.05—0.1

* To reduce soil acidity it is best to apply phosphorus as rock phosphate.

Exceptionally rich soils

On almost all mineral soils found in Indonesia, the application of N and P is required. However, there are some special soils which are very rich in K and/or Mg, and in these soils the application of K and/or Mg fertilisers is not required, or only required in small quantities. There are no exceptionally rich peat soils.

If soil analysis has not been carried out, then the presence of exceptionally rich soils in the plantation needs to be deduced from other factors. The following steps can be followed:

Step 1.	Discuss with the farmers in the plantation area about their manuring practices.
Step 2.	Visit a number of plantations in the area which have been manured poorly and check for the presence of deficiency symptoms (Section 4) in the lower leaves: Potassium deficiencies are very commonly observed and indicate that sufficient application of K fertilisers is likely to be required on the soil type in the plantation area. Magnesium deficiencies are less commonly observed, but can still be found regularly in poorly manured plantations or in palms planted on eroded slopes. Presence of Mg deficiency symptoms indicates that Mg fertiliser application is likely to be required on the soil type in the plantation area. Boron deficiencies are commonly observed and the application of B fertilisers is usually required.
Step 3.	In case of doubt, check the number of black bunches in the plantations, as well as the bunch size, and discuss the yields of the plantations with the farmers. The presence of leaf deficiency symptoms in combination with poor yields is a good indicator that application of sufficient fertiliser is required.
Step 4.	The absence of deficiency symptoms combined with high productivity, even though certain nutrients were not applied or applied in small amounts during several years, may indicate that the soils are exceptionally rich in these particular nutrients. In such cases the application of these nutrients is not required. This can be temporary, as soils can get depleted after several years of high productivity.

Fertiliser application and lack of money

If not enough money is available to buy all the recommended fertilisers, do not leave out the more expensive fertilisers but follow these recommendations:

• Apply fertilisers correctly and in several rounds, so that losses are as small as possible.
• If there are any deficiency symptoms, give priority to applying the fertilisers which are needed to correct the deficiency.
• Do not save on potassium (K) and nitrogen (N) fertiliser, as these nutrients are most important for oil palm and do not stay in the soil for long.
• Magnesium (Mg) is important, but as long as there are no deficiency symptoms, you may decide to reduce application or apply the cheapest fertiliser type (e.g. dolomite).
• If enough phosphorus (P) was applied in the past, it is acceptable to apply less for one year, or to use a cheaper fertiliser type (e.g. rock phosphate).
• If the palms do not show deficiency symptoms, it is acceptable not to apply boron (B) for one year. However, in the next year application will be necessary again, especially in plantations with good production.
• Keep in mind that if too little fertiliser is applied now, yield will go down two to three years later. Fertilisers are a necessary investment and buying them should be a priority.

Acknowledgements

The material from Fertiliser recommendations is sourced from Smallholder Oil Palm Handbook and put together by Lotte Suzanne Woittiez (Wageningen Universit) and Haryono Sadikin, Sri Turhina, Hidayat Dani, Tri Purba Dukan, and Hans Smit (SNV) in August 2016. See Module 4: Fertiliser Application for more information.