Knowledge Based Information on Coconut :: Irrigation Management

Nutrient and their Requirements

Essential elements in coconut nutrition

Of the primary nutrients, potash (K) has been found to be the most important in coconut cultivation, followed by nitrogen (N). There is a general response to the application of K and N; while response to phosphorous (P) is seen only in certain restricted and localized condition.
Among the secondary nutrients, magnesium (Mg) and chlorine (Cl) have beneficial effects, followed by calcium (Ca), Sulphur(S) and sodium (Na). Among micro-nutrients, zinc (Zn), boron (B) and manganese (Mn) are required under certain restricted conditions.

Effects of Nutrients: Nitrogen:The supply of nitrogen which is a constituent of plant cells as well as chlorophyll, the green colouring matter of leaves, is of great importance for the rapid development and growth of the trees. Nitrogen promotes the developments of the vegetative parts of the plant especially the leaves and shoots as well as to increase the number of leaves. Phosphorus: Phosphorus is found especially in leaves and seeds and also in parts of the plants where vigorous cell division is taking place. It plays an important role in root growth and increased yields. Potassium: Potash has its important and specific functions apart from those, which it jointly performs in association with phosphorus. It regulates the water economy of the plant and so is indispensable for the rational utilization of limited water supplies for the production of the highest possible yields. It enables the plant to withstand drought. Potash is known to help root development, enabling the palm to take up more nutrients from the soil. Since potash is particularly necessary for the formation of sugar, fat, and fibrous material, the coconut palm may be expected to have a high requirement of potash. Manganese: It aids in the formation of chlorophyll in leaves. It is present mostly in lower leaves and provides favourable growth conditions during younger stages of palm. Magnesium: Magnesium (Mg) has beneficial effects on the general growth and productivity of palm. Magnesium improved production of more female flowers, high setting percentage and more number of nuts per bunch. It also plays an important role in photosynthesis and greenness of leaves. Sulphur: Sulphur increases the oil content and reduces N and sugar contents.

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Manuring in Tamil Nadu – TNAU Fertilizer may be applied in two equal splits during June – July and December – January. Apply manures and fertilizers in circular basins of 1.8 m from the base of the palm, incorporate and irrigate sufficient moisture should be present at the time of manuring. Phosphorous may be applied as super phosphate in the basins and incorporated or as DAP through drip when good quality of water is available. Fertilizer Requirement of Palms – TAMIL NADU

Time after Planting

Compost (kg/palm/year)

Blanket Recommendation (g/palm)

Straight Fertilizer (g/palm)

Urea

Super Phosphate

Muriate of Potash

6th month after planting

–

2nd year

140

300

500

3rd year

280

160

600

610

1000

4th year

420

240

900

910

1500

5th year

560

320

1200

1300

2000

Time after Planting

DAP & Others (g/palm)

17:17:17: Complex (g/palm)

20:20:0 complex (g/palm)

DAP

Urea

MOP

17:17:17 Complex

Urea

MOP

20:20:0 complex

Urea

MOP

2nd year

174

235

500

470

130

365

400

130

500

3rd year

348

470

1000

940

260

730

800

260

1000

4th year

522

700

1500

1410

390

1095

1200

390

1500

5th year

696

940

2000

1880

520

1460

1600

520

2000

Under irrigated conditions, the fertilizers can be applied in 3-4 equal split doses. 1000:500:2000gm NPK/ palm/year is to be recommended for hybrid coconut in coastal Tamil Nadu. Fertigation may be done at monthly intervals with 75% of the recommended dose of the above fertilizers.

Recommended Micro Nutrient Mixture – Tamil Nadu Quantity recommended: 1 kg/palm/year (Ferrous, Manganese, Zinc, Boron, Copper) Method of application: Soil application (Basal) apply along with farm yard manure. Top of page

Manuring in Karnataka Organic Matter: FYM/ Compost: Before Planting – 12.5 t/ha. Every Year – 50 kg/palm

Fertilizers Requirement for Pre-monsoon Condition

Time after planting

Blanket Recommendation (g/palm/year)

Straight Fertilizer (g/palm/year)

Pre monsoon

Post Monsoon

Pre monsoon

Post Monsoon

Urea

SSP

MOP

Urea

SSP

MOP

1st year after planting

Planting in May – June

135

–

110

250

225

2nd year after planting

135

110

270

110

250

225

240

500

450

3rd year after planting

110

270

220

160

540

240

500

450

480

1000

900

4th year after planting

170

120

400

330

200

800

370

750

670

720

1250

1335

Time after planting

DAP & Others (g/palm)

Pre monsoon

Post monsoon

DAP

Urea

MOP

DAP

Urea

MOP

1st year after planting

–

225

2nd year after planting

225

175

170

450

3rd year after planting

175

170

450

348

340

900

4th year after planting

260

267

670

435

545

1335

Time after planting

17:17:17: Complex (g/palm)

Pre monsoon

Post monsoon

17:17:17 Complex

Urea

MOP

17:17:17 Complex

Urea

MOP

1st year after planting

–

235

158

2nd year after planting

235

158

470

315

3rd year after planting

470

315

941

130

630

4th year after planting

705

110

465

1176

282

664

Time after planting

20:20:0 complex (g/palm)

Pre monsoon

Post monsoon

20:20:0 complex

Urea

MOP

20:20:0 complex

Urea

MOP

1st year after planting

–

200

225

2nd year after planting

200

225

400

450

3rd year after planting

400

450

800

130

900

4th year after planting

600

110

670

1000

282

1335

Apply MgSO4 for bearing trees @ 0.5 kg/palm in coastal region (Note: Lime incorporation – 15 days prior to application of fertilizer during September – October.

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Manuring in Kerala Manuring young palms – KAU: For the first two years after planting under rainfed conditions, apply fertilizers in two split doses at the rates shown in the table given below Fertilizer Requirement of Young Palms in Relation to that of Adult Palms- KERALA (Under Rainfed Condition)

Time after planting

Blanket Recommendation (g/palm)

Straight Fertilizer (g/palm)

Urea

Super Phosphate

Muriate of potash

3 months

120

110

200

1st year

167

107

400

360

670

660

2nd year

334

214

800

720

1340

1330

Time after planting

DAP & Others (g/palm)

17:17:17: Complex (g/palm)

20:20:0 complex (g/palm)

DAP

Urea

MOP

17:17:17 Complex

Urea

MOP

20:20:20 complex

Urea

MOP

3 months

200

188

146

160

200

1st year

232

271

660

630

130

486

535

130

660

2nd year

464

545

1330

1258

260

973

1070

260

1330

Note: Under irrigated conditions, the fertilizers can be applied in 3-4 equal split doses. In the case of low lying areas, apply fertilizer after water table recedes in one single dose or in two split doses as conditions permit. In all types of soils that are low in organic matter content (except reclaimed clayey soils and alluvial soils), apply organic matter @ of 15-25 kg/palm/year during June-July from the second year of planting.

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Fertilizer Requirement of Adult Palms- KERALA (Under Rainfed Condition)

General Recommendation (g/palm)

Straight Fertilizer (g/palm)

Urea

Amm. Sulphate

Super Phosphate

Rock Phosphate

Muriate of Potash

(a) Average management

340

170

680

750

1650

1060

570

1130

(b) Good management

500

320

1200

1080

2000

1070

1990

For reclaimed clayey soils ( as in Kuttanad)

250

350

900

540

1190

2190

1170

1495

Red loam soils (southern Kerala)

680

230

900

1480

3240

1440

770

1495

Hybrids & High Yielding Palms

(a) For irrigated areas

1000

500

2000

2170

4880

3130

1670

3320

(b) For rain fed conditions

500

320

1200

1090

2380

2000

1070

1990

Time After Planting

DAP & Others (g/palm)

17:17:17: Complex (g/palm)

20:20:0 Complex (g/palm)

DAP

Urea

MOP

17:17:17 Complex

Urea

MOP

20:20:0 Complex

Urea

MOP

(a) Average management

370

595

1130

1000

370

847

850

370

1130

(b) Good management

695

814

1990

1882

390

1460

1600

390

1990

For reclaimed clayey soils ( as in Kuttanad)

760

297

1495

1470

625 (SSP)

1080

1250

625 (SSP)

1495

Red loam soils (southern Kerala)

500

1280

1495

1353

977

1112

1150

977

1495

Hybrids & High Yielding Palms

(a) For irrigated areas

1085

1750

3320

2940

1085

2490

2500

1085

3320

(b) For rain fed conditions

695

814

1990

1882

390

1460

1600

390

1990

Under irrigated conditions, fertilizers can be applied in 3-4 equal split doses.
In the case of low-lying areas, apply fertilizers in one single dose after water table recedes or in two split doses as conditions permit.
The application of organic materials such as forest leaves, cattle manure, coir dust or coconut shredding at 10 kg per pit in the first three years and 15-25 kg thereafter will be useful to obtain better establishment of coconut palms in sandy soils and in coastal situations.
In situations where the available P2O5 status of the soil is more than 10 ppm, application of phosphatic fertilizers can be skipped for a few years until the status of P2O5 reaches 10 ppm.
For sandy and sandy loams of Onattukara and similar situations and also for hybrid palms grown in root (wilt) affected areas, apply 500 g N + 300 g P2O5 + 1000 g K2O along with 500 g MgSO4 / palm / year.
Application of MgSO4 to coconut palms earlier confined to root wilt affected areas is recommended for the whole state (ad hoc recommendation).
The N:P2O5:K2O recommendation given for high yielding palms is, in general, sufficient for palms yielding up to 100 nuts per year. For palms yielding more than 100 nuts per year, an additional dose of 10 g N, 5 g P2O5 and 15 g K2O may be supplied for every nut exceeding 100 nuts (ad hoc recommendation).

In laterite soils, 50% of the K2O requirement of coconut can be substituted by Na2O supplied in the form of sodium chloride.

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Time, Frequency and Method of Fertilizer Application: The proper time for the application of fertilizers is when sufficient moisture is available in the soil. Under rainfed conditions, apply fertilizers in two split doses, 1/3 at the time of early southwest monsoon showers in April-June and 2/3 in September-October. Under irrigated conditions, apply fertilizers in three or four equal doses in April-May, August-September, December and February-March. Apply lime or dolomite during April-May, magnesium sulphate during August-September and organic matter during June-July. For an adult palm 1 kg dolomite or 1 kg lime + 0.5 kg MgSO4 is required per annum. Apply fertilizers and manures in circular basins at a radius of 2.0 m from the base of the palm and 10 cm deep, opened after the onset of southwest monsoon. Split doses can be applied with irrigation water in summer months. Application of MgSO4 at the rate of 500g/palm/year for adult coconut plantations is recommended. Boron deficiency causes characteristic malformation of leaves like hook leaves, nut cracking, drying of the female flowers etc. Soil application of Borax @ 50 g/tree twice at monthly intervals after appearance of the first symptom corrects the deficiency. In the root (wilt) disease affected area, it has been recommended to apply Borax @ 300 g/seedling and Borax @ 500 g/ adult tree. Application of magnesium @ 500 g MgO per palm is advantageous for the management of root (wilt) diseased palms to restore palm vigour and sustain the productivity. Top of page

Biofertilizers: The root regions of coconut palm are inhabited by a number of free living and associative symbiotic nitrogen-fixing bacteria having nitrogenase activity. The association of N2-fixing Azospirillum amazonense with the roots of coconut palm has recently been confirmed. The other associative nitrogen fixers include Azospirillum lipoferum, Azospirillum brasilense, Herbaspirillum frisingense, Bacillus spp., Burkholderia spp., Azoarcus spp., Arthrobacter spp. and many more which are yet to be identified. Some of these are capable of fixing nitrogen even in the presence of nitrogen fertilizer.

Microbial combinations may have very great potential for plant growth enhancement. While raising coconut seedlings in coir dust-soil mixture, Beijerinckia indica and associative diazotrophs such as Azospirillum, Arthrobacter, Azoarcus, Herbaspirillum, Bacillus, Burkholderia and Pseudomonas are promising microbiological inoculants which enhances the growth and performance of seedlings.

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Vermicomposting: The local species of Eudrilus identified from coconut garden which is superior to other species in composting of coconut plantation wastes. This earthworm can be multiplied fast in a 1:1 mixture of cowdung and decayed organic wastes. Keep 10 kg of this mixture in bucket and release 50 to 100 worms. Mulch the mixture with grass and cover with a net. Maintain the moisture. In 1 to 2 months 150 to 300 g earthworm will be produced.

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Coirpith Composting: Coir pith contains very less nitrogen and has large amounts of lignin and phytotoxic polyphenols and has to be composted before using as manure. Exposure to rains and sunlight for many years results in loss of problematic chemicals and the use of weathered coir pith may be advantages. Fresh coir pith has a wide C:N ratio (about 100:1) and for initiating microbial action, nitrogenous organic or inorganic materials are to be added. Additionally, fortification with rock phosphate at the rate of 10kg per ton of coir pith can also favor microbial action. The well known technology for composting coir pith using Pleurotus sajor caju may be utilized for large scale composting. For composting one ton of coir pith, 5kg of urea and 5 bottles of Pleurotus spawn is required. 100 kg of coir pith is spread on a level land in shaded place and 1 bottle of spawn is sprinkled over it. The spawn layer is covered with 100 kg coir pith and 1 kg urea is sprinkled over it. This process is repeated 5 times to get a heap, which is protected from direct sunlight and rain. Proper moisture to be maintains in the heap and is allowed to undergo degradation for 1 month. This compost can be used as manure in coconut plantations. Top of page

Recycling of Palm Waste: Recycling of palm waste is very much beneficial especially for maintaining the availability status of micronutrients and trace elements. Palm wastes like coconut leaves, crown waste, dried spathes, husk etc. may be deposited in a small trench of convenient length, 0.5 m to 0.75 m wide and 0.3 to 0.5 m deep at a distance of 2-2.5 m away from the base of the trunk. Fill up this trench with the palm wastes along one side of the palm (say north) in one year, opposite side (south) in the next year, east in the third year and so on. This practice of organic recycling of waste has been found to improve the growth and productivity of the palms.

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TNAU Coconut Tonic: For nut bearing coconut, root feed TNAU coconut tonic @ 200ml/palm once in six months. Top of page

Bio-Fertilizer Recommendation

50 g of Azospirillum
50 g of Phosphobacteria ( or ) 100 g Azophos
50 g of VAM

Mix all the contents in sufficient quantity of compost or FYM and apply near feeding roots once in 6 months / palm starting from planting. Don’t mix with chemical fertilizers and pesticides

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Organic Recycling: Any one of the green manure crops like sunnhemp, wild indigo, Calapagonium or Daincha may be sown and ploughed in situ at the time of flowering as a substitute of compost to be applied. Sow sunnhemp @ 50 g/palm in the basin and incorporate before flowering. Coir pith compost/vermicompost made from coir pith/ coconut leaves/ other wastes from coconut grove can be applied. Top of page

Physiological Disorder

Deficiencies for nutrients such as nitrogen, phosphorus, Potassium and micronutrients are very common in coconuts cultivation. Symptoms are often observed in coconut gardens where the trees are not properly fertilized especially with organic manures. (i) Major Deficiency

Nitrogen (N) Deficiency

Symptoms: N deficiency is typically caused by insufficient N in the soil. Nitrogen deficiency begins as a uniform light green discoloration / yellowing (uniform chlorosis) of the oldest leaves. Yellowing starts from tip to base of the lower leaves and will proceed up. As the deficiency progresses, younger leaves will also become discoloured. Older leaves are golden yellow colour. Growth virtually stops when N deficiency is severe and become shedding of leaves.

Diagnostic Techniques: Nitrogen deficiency is easily diagnosed by symptoms alone, although leaf nutrient analysis can also be helpful. Nitrogen deficiency can be confused with Fe or S deficiency, although the chlorosis in those deficiencies is typically most severe on the youngest leaves. The reverse is true for N deficiency. Management: Foliar application of 2% urea thrice at fortnightly interval or soil application of 1-2 kg urea / tree or Root feeding of 1% urea 200 ml twice a year.

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Phosphorus Deficiency Symptoms of damage: Deficiency occurs in acid and alkaline soils.

Purple coloration in leaves (In severe cases may leaves turn yellow before drying prematurely)
Sluggish growth
Leaves stay upright
Premature leaf shedding

The growth, leaf size and leaf number reduced. The root growth is restricted if phosphorus deficiency is recorded. There are no clear visual symptoms of phosphorus deficiency other than stunting and decrease in yield. This deficiency common in wide range of soil Management: Foliar spray of DAP 2% twice at fortnightly interval or soil application of FYM 5kg/tree. Root feeding of 1% DAP 2 ml twice a year.

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Boron (B) Deficiency Symptoms: Boron deficiency is caused by insufficient B in the soil. It may be caused by soil drying and high soil pH, while temporary B deficiency is caused by heavy leaching.

Symptoms always occur on newly emerging leaves, and remain visible on these leaves as they mature and are replaced by younger leaves.
One of the earliest symptoms of B deficiency on coconut palm is leaf wrinkling and manifested as sharply bent leaflet tips, commonly called “hook leaf”. These sharp leaflet hooks are quire rigid and cannot be straightened out without tearing the leaflets. Leaves have a serrated zigzag appearance.
One of the most common symptoms of B deficiency is the failure of newly emerging spear leaves to open normally. In a chronic stage, multiple unopened spear leaves may be visible at the apex of the canopy.
Boron deficiency also occurs in inflorescence and nuts. The inflorescence and nuts are become necrotic.

Diagnostic Techniques: Boron deficiency symptoms are quite distinctive and are usually sufficient for diagnosis by themselves. Manganese deficiency produces symptoms similar to those of B deficiency, but no other common deficiency produces symptoms that could be confused with those of B deficiency. Because B deficiency is so transient in nature, the element is immobile within the palm (cannot move from one leaf to another), and deficiencies affect only leaf primordial developing within the bud area, leaf analysis is not particularly useful.

Application of Boron to Coconut

Stage

Source (choose one)

Rate

Time and Method

Nursery

Borax/Sodium Tetraborate

0.2% (2 g/L H,O), (75-100 ml/seedling)

1-2 times by spraying or drenching

1 year old

Borax/Sodium Tetraborate/Octaborate

5-10 g/plant

Once each year to soil

2-3 years old

Borax/Sodium Tetraborate/Octaborate

15-20 g/plant

Once each year to soil

4 years old and more

Borax/Sodium Tetraborate/Octaborate

30-50 g/plant

Once every 2 years by soil

Popularity: 4%

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Manganese (Mn) Deficiency: Manganese deficiency is very common on alkaline soils, but can occur in containers if drainage is poor or soils temperatures are cool. Symptoms: The newest leaves of Mn deficient palms emerge chlorotic with longitudinal necrotic streaks. As the deficiency progresses, newly emerging leaflets appear necrotic and withered on all but basal portions of the leaflets. This withering results in a curling of the leaflets about the rachis giving the leaf a frizzled appearance (‘frizzle top’). On new leaves of Mn-deficient palm, necrotic leaflet tips fall off and the leaf has a signed appearance. In severely Mn- deficient palms, growth stops and newly emerging leaves consist solely of necrotic petiole stubs. Diagnostic Techniques: Visual symptoms may be sufficient to diagnose this disorder, but leaf nutrient analysis is also suggested, since symptoms of boron (B) deficiency can be similar. Late stage potassium (K) deficiency symptoms are virtually indistinguishable from those of Mn deficiency at a distance and close examination is required to look for characteristic longitudinal streaking and basal symptom distribution of Mn deficiency. Management: Soil application of MnSO4 @ 25kg/ha

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Magnesium (Mg) Deficiency: Magnesium deficiency is caused by insufficient Mg in the soil. Magnesium is readily leached from sandy soils and other soils having little cation exchange capacity. High levels of nitrogen (N), Potassium (K), or calcium (Ca) in the soil can also induce or exacerbate Mg deficiencies. Symptoms: Magnesium deficiency appears on the oldest leaves of palms as broad chlorotic (yellow) bands along the margins with the central portion of the leaves remaining distinctly green. In severe cases leaflet tips may become necrotic. Older leaves become bronzed and dry appearance. Leaflets show necrosis and turn to reddish brown with translucent spots yellowing starts at the tip and spreads to the base. Diagnostic Techniques: Visual symptoms alone are usually sufficient to diagnose Mg deficiency. Magnesium deficiency symptoms differ from those of K deficiency in that symptom severity of discoloration K- deficient leaves is usually orange to bronze, shading gradually to green at the base of the leaf, whereas Mg- deficient leaves have distinctly green leaf centers and bright lemon yellow to orange margins. Management: Soil application of MgSO4 1-2 kg/tree/year. Root feeding of 200 ml of 0.2% MgSO4 twice a year.

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(ii) Minor Deficiency Sulphur Deficiency Symptoms: Typical symptoms are yellowish-green or yellowish-orange leaflets. Older leaves are remaining green. Leaves droop as the stem becomes weak. In older palms, leaf number and size are reduced. Sometimes an apron of dead fronds develops around the stem due to weakness of the rachis. Nuts may fall prematurely. Copra is rubbery and of poor market quality. Management: Soil application of gypsum 2 – 5 kg/tree/year. Root feeding of 0.2% gypsum. Top of page

Iron Deficiency Symptoms: Iron deficiency usually appears on palms growing in poorly aerated soils or those that have been planted too deeply. Water logged soils and deep planting effectively suffocate the roots and reduce their effectiveness in taking up nutrients such as Fe. The main symptom of iron deficiency is chlorosis or yellowing between the veins of new leaves (Uniform chlorotic new leaves as the deficiency progresses, the tips become necrotic and leaf size reduced. Management: Application of Feso4 0.25 to 0.5 kg/tree/year Top of page

Zinc Deficiency Symptoms: Zinc deficiency is characterized by formation of small leaves wherein the leaf size is reduced to 50%. Leaflets become chlorotic, narrow and reduced in length. In acute deficiency, flowering is delayed. Zinc deficiency will also lead to button shedding. Its occurs mostly in saline soils. Management: Soil application of ZnSO4 @ 25kg/ha Top of page

Calcium Deficiency Symptoms: Young leaves exhibit narrow white bands at margins. Interveinal chlorosis. Rusty appearance in leaf margin. Rolling up of leaves. Occurs only in acid soil Management: Soil application of lime based on lime requirement and root feeding of 1% calcium nitrate. Top of page

Copper Deficiency Symptoms: Coppery bluish leaf. Rolling of terminal leaves due to loss of turgor. Leaves appear to be bleached grey. Fail to produce flowers Management: Soil application of CuSO4 @ 25 kg per ha. Top of page

Protection technologies of Coconut: Management practices include growing green manure (sun hemp) as an intercrop and ploughing in situ. Application of 650g urea, 1kg super phosphate and 1 kg potash per tree along with 25 kg farmyard manure (FYM) once in six months in June- July and December- January. Application of micronutrients viz., magnesium sulphate 150g, zinc sulphate 75g, borax 50g along with 10kg of well decomposed FYM per tree prior to rainy season. These measures help overcome nutritional disorders and restore the vigour and productivity of the trees. Top of page

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