The effects of nitrogen and potassium on the growth and foliar nutrient levels of immature MAWA coconut palms grown on an ultisol

H.S. Goh and D. Sahak

Abstract

The effects of four levels each of nitrogen and potassium(1,3,5 and 7 kg/ palm per year of ammonium sulphate and muriate of potash) on the growth and foliar nutrient levels in immature MAWA hybrids on Rengam soil were monitored from l982 to 1986.N applications but not K significantly(p =0.05) increased annual frond production.N and K treatmentsa lone or in combination did not significanly affectt he number of fronds retained, number of leaflets/frond,frond length and palm height. Increasing N application significantly(p : 0.05)increased the N-leaf levels.The response was quadratic in both the third and fourth year. Increasing rates of K significantly (p :0.05) increasedt the foliar K but not the N levels.The response was quadratic during the third year and linear in the fourth when the palms came into bearing. Mg-leaf levels decreased significantly (p = 0.05) and linearly to increasingra tes of K or in the fourth year but to K only in the third. N applicationsin the third year interacted with K to decrease  (p: 0.05)M g leaf levels. A comparison of the foliar N and K levels in this experiment was attempted and more realistic critical levels of N and K for palms grown on tropical inland soil were proposed. Preliminary data from this study indicate that MAWA palms on inland soil respond to N and K applicationsm, ore in foliar nutrientc ontent than in vegetativeg rowth. The generalg rowth of the palms,on the whole, is very promising.

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