Severe N deficiency is rarely seen on old palms. Nitrogen deficiency is expressed in uniformly pale, yellow green leaflets and a sharply reduced growth rate. Midrib tissues become bright yellow, Nitrogen deficiency may also be caused by poor drainage.
Phosphorus deficiency does not produce leaf symptoms in oil palm. However, the trunks of affected palms are narrow and tapered
Potassium is the nutrient required by oil palm in largest amounts, anddeficiency symptoms develop on most soils unless K fertilizer is applied. Continued K deficiency leads to a progressive decline in yield and plant health. A number of different symptoms indicate K deficiency or an imbalance of K with other elements. The most typical and widespread form of K deficiency is known as “confluent orange spotting” . The first signs of K deficiency are pale green spots on the pinnae of older fronds. In a more advanced stage, the rectangular spots become orange-yellow and transmit light when held up to the sky. Later, the tips of leaf pinnae start to dry up. In very severe cases, entire older fronds may dry up. Some palms show symptoms similar to K deficiency known as “genetic orange spotting”
Boron deficiency is expressed in a range of leaf symptoms. However, in all cases the distal end of leaflets at the tip of the frond are most affected. Pinnae are misshapen, stiff and brittle. “Hook leaf” is one typical symptom of B deficiency
Severe Mg deficiency results in the development of bright orange color in older fronds. The orange discoloration is very pronounced on the upper rank pinnae exposed to sunlight, whilst lower rank and shaded pinnae remain green. Leaf veins also stay green for a longer period. Older fronds dry up and die under conditions of severe Mg deficiency. Planters should be able to distinguish between Mg and K deficiency and a healthy leaf
Manganese (Mn) deficiency is not common, but has been reported on soils with high exchangeable Mg status and insufficiently compacted peat soils where palms are suffering from drought. Manganese deficiency shows as a yellowing of interveinal areas. In contrast to Mg deficiency, the symptoms are found on young rather than on older fronds. The symptoms are equally pronounced on upper (sun exposed) and lower (shaded) rank pinnae. Manganese deficiency can occur on peat and very sandy soils and is sometimes associated with high leaf Mg status.
Zinc (Zn) deficiency is not common in oil palm but may be induced under high soil P status and occurs on ultrabasic and ultramafic soils with high soil pH. It is also believed to be a factor involved in the “Peat Yellows” condition found on peat soils. Zinc deficiency has also been reported on shallow peat soils overlying sand, particularly where large amounts of soluble P fertilizer have been applied. It appears as small, narrow white streaks on lower and mid-crown fronds. A different condition that produces blotchy leaf symptoms has also been identified tentatively as Zn deficiency.
Iron (Fe) deficiency is very rare in oil palm and occurs where soil pH is very high (i.e., more than 7.5). The deficiency has been observed where palms are grown over coral outcrops or on spots where white ant hills have been levelled. It is easily identified, as symptoms appear first on the youngest fronds, which appear droopy and show diffuse blotchy yellowing and white freckles.
Copper (Cu) deficiency is common on deep peat soils and occurs also 30 on very sandy soils. It appears initially as whitish yellow mottling of younger fronds. As the deficiency intensifies, yellow, mottled, interveinal stripes appear and rusty, brown spots develop on the distal end of leaflets. Affected fronds and leaflets are stunted and leaflets dry up. On sandy soils, palms recover rapidly after a basal application of 50 g CuSO4. On peat soils, lasting correction of Cu deficiency is difficult, as applied CuSO4 is rendered unavailable. A promising method to correct Cu deficiency on peat soil, developed by the authors, is to mix CuSO4 with clay soil and to form tennis-ball sized "copper mudballs" that are placed around the palm and that provide a slow-release source of available Cu.
Micronutrient elements, iron, manganese and zinc are not generally found limiting in the nutrition of oil palm on acid soil conditions. Boron deficiency is occasionally found on young palms in the plantation showing a reduction of leaf area in certain leaves producing incipient "little leaf", advanced "little leaf" with extreme reduction of leaf area and bunching and reduction in the number of leaflets and "fish-bone" leaf. The "fish-bone" leaves are abnormally stiff with leaflets reduced to projections. Leaf malformations including "hook leaf" and corrugated leaflets are some other associated symptoms. Soil application of 50 - 200 g borax decahydrate, per palm, depending on age, and severity of symptoms is practiced for correcting the malady
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Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage
Last Modified : 4/2/2020
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