Organic Manures in Tea

8/6/2019 Organic Manures in Tea

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~,ORGANIC MANURES IN TEAD.P. Verma and S. Venkatesan*

Tea soils continue to bedegraded due to lack ofadoption of appropriate soilconservation measures and alsocontinue to be depleted due toadditions (supply) not keepingpace with removals (demand). Itis unlikely that soil depletion willever cease to be a problem.However, it is equally likely thatas per the present knowledge, ifall the available plant nutrientsources are adequately andefficiently utilised, nutrientdepletion can be reduced to aconsiderably low level. Nosingle source of nutrient be itinorganic fertiliser, organicmanure or bio fertiliser can meet

TABLE 1. NUTRIENT COMPOSITION (%) OF TEA PLANT

*Recycled at pruningUPartly removed as fuel at pruning

the cycle at different points. Thesound strategy isthus one wherechemical fertilisers and organic

essential. Tea being a leaf crop,nitrogen content is the highestfollowed by potassium, calcium,

Element Flush Foliage *Twig* Wood UN 3.50-5.00 2.08-2.25 0.99-1.15 0.82-1 .05K 1.49-2.39 1.12-1.87 0.50-0.86 0.38-0.51Ca 0.32-0.45 0.64-0.87 0.20-0.32 0.25-0.34P 0.24-0.32 0.12-0.15 0.05-0.08 0.02-0.03S 0.21-0.24 0.28-0.34 0.11-0.18 0.08-0.12Mg 0.18-0.19 0.14-0.21 0.08-0.11 0.04-0.08


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i .-deeper into the soil and absorbnutrients from lower strata of thesoiI beyond the reach of tea rootsand trap some of the nutrientsleached down from the top soil.When leaves, pods and twigs ofshade trees drop on the surfacesoil, the nutrient present in thedroppings, in due course,become available to the roots.The beneficial effect of shade ismost pronounced in the absenceof fertiliser nitrogen andprogressively decreases as thelevel of nitrogen fertiliser israised.In south India silver oak(Grevillea robusta) is used aspermanent shade. It is quickgrowing and the dissected leavesfacilitate filtering of light. Withdeep root system and high .rootcation exchange capacity (30-35meq %) it does not compete withtea (16-25 meq %) for either

leaf falls of Grevillea (70 trees /ha) planted at 12.2x12.2 m addapproximately 2.5 tonnes organicmatter, 39 kg of nitrogen, 20 kgof phosphorus and 14 kg ofpotassium per ha/year (Table- 2).In addition, while lopping (70trees/ha) it adds approximately 5tlha of organic matter annuallyand considerable amount ofnutrients are recycled andbecome available for tea plants.In north east India Albiniasinensis, Albizzia odoratissima,Albizzia procera and Dalbergiaassamica are the common shadetrees. Indigofera teysmanii issuitable as a temporary shadeboth in north east and southIndia. The shade tree used 'innorth east India,Albizzia sinensiscasts moderate shade (50 to 60%light intensity). On an average,it adds in the form of leaf, twigand pod droppings 2500 to 5000kg per ha of dry matter annually

3. Management ofPruning litter

Tea prunings contain consider-able amount of nutrients, whichcould be returned to the fieldprofitably. The amount ofnutrients returned to the soil byretention of pruning inmature teaare presented in Table -2. Thefoliage have narrow C:N ratio anddecompose readily yieldingconsiderable quantities of N, Pand K in the pruned andsubsequent years. The woodportions have a wide C:N ratioand decompose slowly whiletwig decomposes at the moderaterate. In the areas where theannual rainfall is below 1500mm, burial of pruning instaggered trenches in alternaterowswill be useful, while in highrainfall areas, chopping of teaprunings and spreading them on


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TABLE3. EFFECTOF MANAGEMENT OF PRUNINGS(NILGIRIS)

in organic matter, damage tofeeder roots and accelerates soilerosion.Treatments Organic matter %Average yield I cycle II cycleKg/ha Surfacesoil Sub-soil Surfacesoil Sub-soilI 6.Organic manures in teanutrition

Chopping and 3234 3068spreading of prunings (+ 4.1) (+ 3.0)Figures in parenthesis denote % increase over control(Source: Pandiaraj, G.T.S.1991. Field practices in Corsely estate.Joint Area Sci. Symp., Aug. 22-24, Coonoor.)

Prunings removedBurialof

31053287(+5.9)runings

29803248(+9.0)

2.73.6

3.65.9

4.15.4

5.0 2.9 4.9

4.MulchingMulching in young tea isa provencultural practice in minimisingsoil erosion, regulating soiltemperature, conservingmoisture, suppressing weedgrowth and enriching the soilorganic matter. It reduces the

5.Chemical Weed ControlIt isadvisable to haveavegetativecover of the soil by retaining theshallow rooted dicot weeds likeBorreria ocymoides, Drymariacordata and Oxa/is corniculata.The Nitrogen, potassi urn andphosphorus added by these

2.34.0 The international organisation forstandardisation (ISO), defines

organic manure / fertiliser asorganic or carbonaceousmaterials, generally of vegetableand / or animal origin, added tothe soil specifically for nutritionof plants and generally containingnitrogen of vegetable and oranimal origin. Organic manureis a very broad term. Materialssuch as farmyard manure,compost and crop residueswhichare bulky and supply lowquantities of major plant nutrientsare termed as bulky organicmanures. Concentrated organicmanures such as oil cakes,slaughter housewastes, fish meal

3.0


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..ABLE 5. ORGANIC MATTER (T/HA) IN TEA FIELDS

(Source: Ranganathanet ai, 1980. Organic matt..~rlux in south Indiantea soils a need for conservation, Planters' Chronicle. 75 (7&8) :309-312)matter (OM) by these sourcesvaries with the elevation andlength of the pruning eycle. Atmid elevation, it is as high as 23t/ha and athigh elevation of 2500m, it reducesto 14 t/ha Table - 5.

green manure should bewitheredbefore stacking in the composttank. Tea wastes, coffee husk,cowdung and animal refuses,straw, weeds, cardamomthrashings, shade tree litters and

base up to 22.5 cm from theground level with no gaps afterwhich it may be alternated withperforated and solid layers ofbrick walls. Alternatively, a pitdimension 4.5 x 2.0 x 1.0 m maybe dug in the soil with slopingsidesto faciIitate aeration. If boththe above options are notavailable, the agrowastes may beheaped on the surface with thesame dimension.c. CompostingAnimal dung and agrowastes areapplied in the tank uniformly bymeans of rake in layers of 15.0 to22.5 cm thickness. A slurry ofcowdung is applied uniformly ontop of each layers. Water maybe sprinkled to wet the layersufficiently. The moisture shouldbe maintained at 50-70 per centfor ideal decomposition. A layerof tank silt is applied over each

SOURCE 500 -1500m 1500 -2000m 2000 -2500mShade tree littersand loppings 44.5 39.5 39.5Tea litters 19.8 14.8 14.8Tea prunings 22.2 24.7 24.7Weeds 4.9 4.9 4.9Cycle Average 91.4 83.9 83.9Length of cycle(years) 4.0 5.0 6.0Annual Averageaddition 22.9 16.8 14.0


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in two instalments. The secondinstalmentfilling should be takenup 15 days after fi rst fi IIing. Tohasten the process ofdecomposition and for thepreparation of balanced compost2.5 kg of sulphate of ammonia(SOA)or 1.5 kg of urea and 3.0kg of rock phosphate may beapplied on each layer ofcowdung, agrowastes and soil oftank size 9 m2. The successivelayersare added till the heap risesto 60 cm above the tank level orabove the ground level in thecaseof pits. Finally the top layeris sealed with a 7.5 cm layer ofmud and cowdung mixture andshaped like a dome and coveredwith straw, coconut leaves andother leafy materials, or it may bethatched to protect the tank fromdirect sun and rain. Bamboosticksare placed at intervals in theheaps to supply air and toexamine the temperature of

narrow C:N ratio and of highmanurial value. One tank (9 m2)can be used thrice in a year forcomposting and can produce 15tonnes of compost annually.8. Coir pith compostThe coir pith is a material thatinvariably discarded after theprocess of making coir rope andis abundantly avai lable incoconut growing areas of TamilNadu and Kerala. For every kgof coconut fibre extracted, 2 kgof coir pith is obtained. Thedisposal of coir pith is a big

problem in these areas. The coirpith can be composted and easilyconverted in to rich sourc.eof nutrients. As the coir pith willnot decompose on its own,'pluerotus' mushroom and ureaare used as a catalyst. For everytonne of coir pith 5 kg of ureaand5 bottles of pluerotus mushroomis required. Coir pith at 1OOkg(5cm x 3 cm) is spread out evenlyin shade. Then a bottle ofmushroom seed (200 g) issprinkled over it. Above it 100kg of coir pith is spread again and1 kg of urea is sprinkled. Thisprocess is repeated in an

TABLE 6. NUTRIENTS IN VARIOUS SOURCESOFORGANIC MANURES

Sources of organic manureParametres Castor Neem Coir pith Coffee Press mudhusk Compostcake cake Compost


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.alternating manner to form 10layers. Water is sprinkled overthe coir pith so as to maintain 200per cent moisture content for 30to 40 days (Satyamurthy, G, TheHindu, December 21,1998).The volume of coir pith getsreduced by half and can be usedas a compost. The nutrients incoir pith compost is given inTable - 6.9. Vermi compostpreparationThe preparation of vermicompost involves three stages,viz., a) Partial digestion ofagrowastes, b) Inoculation andVermi composting and c)Screening and separation.a. Partial digestion ofagrowastes

The procedure is the same as

be added at the base of pit todrain excess water. Another layerof 15 cm loamy soi I shou Id besprinkled on the layer of brokenbricks. This forms the activeground for earthworm activityand is called vermibed. About100 earthworms may beinoculated for an area of 2 m2onthe vermibed. Above that a layerof partially digested agrowastesmay be even Iy spread to athickness of 15-22.5 cm.Cowdungslurry may besprinkledon the surface. Water may besprinkled to sufficiently wet thematerial. Application ofcowdung slurry and water maybe repeated on alternate days fortwo weeks. Moisture content ofthe bed has to be maintained atabout 60 per cent for betterearthworm activity. After twoweeks, another layer of partiallydigested agrowastes may be

slurryandwater maybedoneas .mentioned before. The additionof cow dung slurry and water maybe stopped at the end of threeweeks after second application ofagrowaste under normaltemperature, on 30th day ofsecond application of predigestedcompost material, the vermicompost will be ready for harvestwith a lot of vermicasts. Thefollowing species of earth wormscan be used for the vermicomposting; Lampito mauriti(found in sandy loam soiD,Octochaetona serrata (found inclayey soi I) Lumbricus terrestis(deep boring), Allolobophoracaliginosa (Shallow boring),Eudrilus eugeniae, Eiseniafoetida, Perionyx excavatusand -Pheretima e/ongata.

c. Screening and separation: IVermi compost should be heaped


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.protection against rats, birds andbandicoots, the compost bedsmay be covered with wire meshof suitable thickness anddimension facilitating adequateaeration. For protection againstants, BHC dust may be appliedin bands around vermi composttanks.Vermiculture in teaThe verm i compost can beprepared separately and can bemixed in nursery soil for goodrooting, in infilling and replantedareasfor good establishment andin mature tea fields forenrichment of poor soil organicmatter. Butvermiculture will notbe successfulin teafields becausechemical weed control ispractised, soi I reaction isextremely acidic to very stronglyacidic, organic matter isgenerallylow to medium, during monsoon

b) Organic matter should belessthan 20.0 per cent

c) Carbon: Nitrogen ratio(C:Nratio) -10:1 to 15:1d) Moisture content should not

exceed 25.0 per cente) Pathogens* : absent*Pathogens and heavy metalsoriginate mainly from sewagesludge and urban garbage.The above specification are alsoapplicable for organic manuressuitable for tea plantations. Inaddition, electrical conductivity(EC) is alsoconsideredto judgetheir suitability for use in teafields.EC (1 %) up to 0.50 dSm-1recommended for young tea.EC (1 %)) up to 1.5 dSm-1recommended for mature teaonly.

11. Organic tea manuringCompost, oil cakes and rockphosphate are the main inputs tosubstitute the removal ofnutrients. Nitrogen is alsosupplied by regular lopping oflow and medium shadetreesandleguminous trees (Gliricidiasepium, Gliricidia maculata)which can be grown alongroadsides and other vacantpatches. Bone meal, fish mealand other manures of organic canalso be used if available fromunpolluted environment; woodash can also be applied. Therecommendations on manuringof organic tea are given in Tables8 and 9. Rock phosphate may beapplied in the pruned and thirdyear as placement based on soiltest values. Soi I avai lable Pshould be maintained at andabove 22 ppm. Wood ash may


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..TABLE 9. MANURING OF ORGANIC TEA -OTHER THAN

PRUNED YEAR(For 2500 To 4000 kg made teal ha)

** Neemcake(4.85%N, 0.36% P, 1.03% K)* * * Castor cake (4.82% N, 0.35% P, 1.11% K)be applied only in mature tea dimension of trench should be 2fields except in the pruned year, x 0.3 x 0.45 m at 2 m apartpreferably in dry periods by between the trenches. Trenchesbroadcasting 15 cm away from may be taken across the slopethe collar. Organic manures once in every two to three rowsshould not be broadcasted in the depending on the gradient. Thetea fields. It should be applied in minimum rate is 20 to 25 tlha tothe staggered trenches. The be applied in two equal splits.

12. ConclusionThe crop husbandry practicesviz., shade regulation, retentionof pruning litters in the field,chemical weed control, mulchingof young tea and mature tea inthe pruned year may be followedto enrich organic matter status oftea fields. It is not economical tomeet the whole nutritionalrequirement by organic maturesalone either in young tea ormature tea. The externalapplication of organic manuresmay be followed only in the fieldhaving low organic mattercontent in addition torecommended husbandrypractices for the enrichment ofsoil organic matter. The nitrogendose may be adjusted based onorganic matter statusof tea fields,which is an integrated approachfor sustainable productivity of teain south India.

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Manure Quantity Nutrients(kg/ha)t/ha N P K

Neem cake**(2 split) 5.0 242 18 52Castor cake***(2 split) 5.0 242 18 56Wood Ash 5.5% K(1split) 0.5 - - 28Rock phosphate(20 %P2Os)- 1 split 0.4 - 35 -

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Organic Manures in Tea