Arecanut ,a vital crop in tropical regions ,it affected various nutrient deficiencies that significantly impact its growth, yield, and overall health. It has identified the deficiencies in early ,and provide timely intervention and optimal crop management. the main deficiencies are given below.
Nitrogen deficiency
Nitrogen is a highly mobile element in plant. So when the soil become deficient in available nitrogen, nitrogen from lower leaves will get transferred to growing points. Hence, deficiency symptoms will be first noticed in older and lower leaves.
The initial symptoms will be pale green to light green colour change on leaves. The colour change normally starts from the leaf tip. The severely affected leaves become golden yellow. The plants also show stunted growth. In advanced stages, the symptom will see on other leaves as well.
It can be managed through Add sufficient quantity of organic matter to the soil every year. Check whether the recommended quantity of fertilizers is applied in time.
Go for soil analysis and understand the extent of deficiency. Apply quick release nitrogen fertilizers like urea as per soil test result in split doses.
Phosphorous deficiency
In deficient situations, the root growth will be affected. This results in poor uptake of needed nutrients. The deficiency symptoms will be first noticed in older and lower leaves. Phosphorus deficiency retards root growth and delays flowering.
In young seedlings, leaves appear with shorter petioles, rosetting of the leaves may occur and growth may be restricted. Severe drying of old leaves in seedlings may also occur. In deficiency situations, phosphorus fertilizers have been found to increase the girth at the collar, the number of leaves and rate of leaf production in seedlings
It can be managed through Phosphorus is best absorbed by the roots in the pH range 6.5-7.5. So adjust pH in acidic soils by adding lime . Add bio fertilizers containing phosphorous solubilizing bacteria along with organic manure to increase phosphorous availability. Check whether the recommended quantity of fertilizers is applied in time.
An excess of Iron and Zinc may also cause the symptoms of phosphorus deficiency. Go for soil analysis and understand the extent of deficiency. Apply fertilizers such as single superphosphate for immediate correction or bone meal or rock phosphate for long term correction as per the soil test report.
Potassium deficiency
Potassium is a highly mobile element in plant. So the symptoms first appear on oldest leaves and later spread to young leaves. Translucent yellow or orange spots develop on leaflets. Leaflets show necrotic areas along the margins which later wilt but midribs remain alive.
The leaves turn rough, wrinkled and the margins curl downwards. Older leaves wither and turn brown earlier than usual. The tree appears yellow, the trunk become slender with few short leaves. The number of inflorescences and nuts produced decrease gradually.
It can be managed through Optimum availability of potassium is at soil pH above 6.0. So correct soil pH in acidic soils by adding lime/ dolomite. Add organic matter and wood ash to the soil. Add bio fertilizers containing potash mobilizing bacteria to release non exchangable potassium from soil. Check whether the recommended quantity of potash fertilizer is applied in time.
Calcium deficiency
Calcium is an immobile element in plant. Hence, calcium deficiency is seen mainly in growing points, younger leaves and developing fruits. Initially, round yellow spots with brown centre appear on younger leaves and the spears. These spots, though isolated at first, later coalesce and finally dry out.
Sometimes leaves exhibit crinkling or distortion. Abnormal growth of young leaves and growing points leading to death of the bud. Root systems exhibit abnormalities, with a low number of primary roots. Most of the roots, including secondary and tertiary, rot under severe deficiency. The deficiency results in shorter intermodal length with rosette leaf symptom.
Reduce the deficiency to Check the pH of the soil. If the soil is acidic, apply lime (0.5 to 1 kg/plant/year in two split doses). Dolomite can be used as cheap substitute of lime. High levels of phosphorous can also induce calcium deficiency
In alkaline soil go for application of Gypsum. Calcium has little mobility in the plant. Hence its availability has to be ensured all the time. Boron is needed for calcium utilization. So a boron deficiency can also lead to calcium deficiency. Use high quality areca nut plants for diseases free plants
Magnesium deficiency
The symptoms of magnesium deficiency are seen first in the bottom leaves. Initial symptom is the inter-veinal chlorosis of older leaves. A small margin on either side of the mid-rib of leaflets also remains green. Yellowing starts at the tip and spreads towards base. Gradually, the yellowing proceeds to younger leaves also.
Prolonged deficiency results in yellow orange to orange coloured older leaves, which turn bronzed and dry later on. The youngest leaves remain green. In severe cases, the tip of leaflets shows necrosis and turns to a characteristic reddish- brown colour. Translucent spots may appear on the yellow parts of the leaf. Reduction in nut production will also be there.
Go for soil analysis and confirm the deficiency. Apply Magnesium sulphate (60 gram/plant or 32 kg/ acre) in bands near plants. Application of dolomite will also reduce magnesium deficiency in long run.
However, magnesium and potassium fertilizers should not be used together. High organic matter content some times aggreviate magnesium deficiency.
Born deficiency
Boron is an immobile element in plant. Hence, boron deficiency is seen mainly in growing points, younger leaves and developing fruits. Leaflets, when unfolding, are crinkled and shorter than normal, sometimes showing yellow or yellowish- orange discoloration. In more advanced stages, terminal leaflets remain fused. The tips of these leaflets may be ‘knife-shaped’.
The basal part of the petiole may be without leaflets. Gradually, the spear shortens and the leaves are reduced to an embryonic mid-rib without leaflets. This is the so-called ‘little-leaf’ stage. Production of barren nuts, nut splitting/cracking and nut shedding are other symptom of Boron deficiency. Nut splitting on the inflorescence followed by shedding is one of the most common symptoms.
Boron deficiency is seen more in dry soils. High available phosphorous in soil also hinders boron absorption. Go for soil analysis and confirm the deficiency. Apply Borax (20 gram/plant or 4 kg/ acre) into the soil.
If calcium and boron should not be applied at the same time. Similarly, borax should not be applied with ammonium fertilizers.
Copper deficiency
Copper deficiency leads to reduced growth. It also produces dark green colour on leaves. The leaves will be malformed. New leaves are seen shriveled. A bushy growth is also noticed.
It can be managed through, Apply Copper sulphate (2 gram/plant or 800 gram/ acre) in the soil.
Zinc deficiency
Zinc deficiency affect the arecanut trees. The main symptoms are Irregular and chlorite leaf spots, mottled leaf, small leaves, severe dieback of twigs.
Deficiency can be reduced through apply a foliar spray of 0.5% ZnSO4 solutio.also applay 20kg ZnSO4 . 7 H2O per ha in the field.
Deficiencies can impact arecanut productivity and quality. Properly identified the deficiency symptoms, farmers can ensure healthy and productive arecanut plantations. regular soil testing, apply fertilization to reduce the deficiency and achieving high yields.
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