A REVIEW ON THE EFFECTS OF BIOFERTILIZERS … REVIEW ON THE EFFECTS OF BIOFERTILIZERS AND BIOPESTICIDES ON RICE AND TEA CULTIVATION AND PRODUCTIVITY DEBOJYOTI ROYCHOWDHURY 1,*, MANIBRATA

AREVIEWONTHEEFFECTSOFBIOFERTILIZERSANDBIOPESTICIDESONRICEANDTEACULTIVATIONANDPRODUCTIVITY

DEBOJYOTIROYCHOWDHURY1,*,MANIBRATAPAUL2,SUDIPKUMARBANERJEE3

1DepartmentofBiochemistry,TechnoIndiaUniversity



*CorrespondingAuthor‐E‐mail‐[email protected]

ABSTRACT

In India intensive farming practices yield high product for which chemical fertilizers are used but these fertilizers arenowadaysfoundharmfulbecausetheyarecreatingenvironmentalproblemsandalsotheyareveryexpensive.Extensiveusesofchemicalfertilizershaveadverseeffectsonhumanhealth.Dependenceonchemicalfertilizersandchemicalpesticidesforthe futureagriculturalgrowth will result in further lossof soilquality , acidificationof soil,possibilityofgroundwatercontaminationandhence lossofecologicalbalance.Thesechemical fertilizersandchemicalpesticides thataresprayedonvegetablesandfruitsposestoxicitytothehumanbody.Recentadvancementinthefieldofbiofertilizersarecreatinggrowinglevelofinterestbecausethesefertilizersareenvironmentfriendlyandarehelpinginhavingsustainableagriculturalpractice.Thesebiofertilizersuselivingmicroorganismsthatestablishessymbioticrelationshipswiththeplantsorareaninoculationofmicroorganismswhichpromotestheplantgrowthbyincreasingtheprimarynutrientsupplytothehostplantandalsoretainsthesoilfertility.Similarlyintheuseofchemicalpesticidesmanydisadvantagesareassociatedwithitlikethegeneticchangesinplantpopulations,foodpoisoningandotherhealthproblemswhichleadstocancerandhasmadethebiopesticidestocomeinthepicturewhichmightreducetheuseofthesechemicalpesticides.ThisreviewpaperdescribesthefactsofexperimentalresultsoftheuseofbiofertilizersontwoimportantexportablecropslikeRiceandTeacultivationinIndiaandaswellasinforeigncountries,withthecurrentstatusofbothbiofertilizersandbiopesticidesinIndianAgriculture.

Keywords‐Biofertilizers,Biopesticides,Azolla,Aspergillus,Mycorrhizae,Plantextracts.

1. INTRODUCTION

Agricultureisactuallycalledfarmingorhusbandry.Thismeans that agriculture is the cultivation of plantsanimalsandotherlifeformsforfood,fibres,biofuelsandotherproductsforthewellbeingnessofhumanlife.

InIndiaagricultureisthemostimportantandoneofthemost important and one of the major sectors whichaccounts for 16.6% of total GDP i.e 50% of total workforce.Butfortheproperoutputi.efortheproperyieldofthecropstheuseoffertilizersareveryimportant.Therearetwotypesoffertilizersmainlyinorganicorchemicalfertilizersandorganicfertilizers.Chemicalfertilizersusemineral deposits or are industrially manufacturedthrough chemical processes. Organic fertilizers arefertilizers that use manures and have their origin inplantsoranimals.

In India in the past 50 years history, the chemicalpesticides and fertilizers have played a crucial role inincreasing the agricultural productivity. But theextensive uses of chemical fertilizers have adverseeffectsonhumanhealth. Indiscriminateuseofchemicalfertilizersandchemicalpesticidescontributedin lossof

soil productivity alongwith additionof salts to the soil(Swapnalatthaaggani2013.).

Dependence on chemical fertilizers for futureagricultural growth would mean further loss in soilquality, possibilities of water contamination andunsustainable burden on agricultural system(Rajasekaranetal.,2011).

1.1 A Problem of Using Chemical Fertilizers andChemicalPesticides

Ingeneral land is regardedasanatural resourcewhichhasmany benefits for human beingswhile at the sametime provides a habitat for many living organisms (Pierra 1991). However currently the behaviour andoflandfertilizerhaschangedduetotheincreaseinhumanbeingsor in the increasingpopulationwhich leads toahigher demand of production. Increase in agriculturalproductivity was the main target to meet the humanneeds.Butbecauseofthescarcityoflandthepeoplehasstopped using natural fertilizers and are using thechemicalfertilizersandchemicalpesticidestogainmoreproductivityinaveryshorttimewhichisfatal.

These chemical fertilizers and chemical pesticides arethemain causes of losing soil fertility and are actually

DEBOJYOTI ROYCHOWDHURY et al. DATE OF PUBLICATION: DEC 10, 2014

ISSN: 2348-4098 VOL 2 ISSUE 8 NOV-DEC 2014

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causinghugeamountof soil and landdegradation (Liuetal2009.).

1.2 Fertilizer Effects on Human Being andEnvironment

These pesticides are adversely affecting the humanhealth.Pesticidescanenterhumanbodybythreeways‐a) flow directly by mouth, b) infiltrate by skin, and c)breathing(Yong,1994).Moreover,pesticidesalsobringsa lot of issues to the people who digest the chemicalfertilizers, for example, skin cancer, or effecton thegrowth of a baby (Yong, 1994). Currently, pesticideshavebecomemuchmoreseriousforlong‐termresistantinhumanbodyaswell as in foods suchasmeat, fruits,vegetables, and other productions with pesticideresidues(R.S.Battu,etal2004).

1.3GroundWaterContamination

The biggest issues faced during the use of chemicalfertilizers are ground water contamination. Nitrogenfertilizers breaks down to nitrates and travels easilythroughthesoilandas theyarewatersoluble theycanremain in that position for decades and theseaccumulation is causing the problem. Theseaccumulationsofchemicalsleadtowaterpollutionbothsurfaceandgroundwater

1.4LossofSoilFertility

Agriculturecanprovidepositiveandnegativeimpactsonsoiluse,andtheuseoffertilizerscanreducethenaturalnutrients on the soil surface(Fred, 1991). Moreover,chemical fertilizers are more resistant in theenvironment than the natural fertilizer because itscombined with chemicals which in some casesare harmful to the environment‐especially, on soilfertility because most of the microorganism decreasefollowing the increase of the chemical fertilizersused (Katsunori, 2003 Because agriculture is heavilydepended on the environmental resources, directimpacts are felt by local farmers because the use offertilizer on their agriculture land and lose of theirecological system from the pollution in the waterresources(LIU Yu, et al., 2009). Interestingly, if peopleapply high level of chemical fertilizer or pesticide ontheir farm land day in, day out, one problem will beemerging from pesticide absorption of their crop isreducedpestcontrol, thebadinsectswillberesistant ifyou apply chemical fertilizers for long period butoppositely beneficial insects will decline leading to thelossofpest control. Forexample: farmersusepesticidefor protecting their cucumber, thus they must applychemicalfertilizertokilledtheinsectsbutunfortunatelythose insects are residue with the fertilizer providingwarmth and other micro‐organisms which live on theground suffer from those fertilizer, micro – organismswhich play a vital role in the improvement of the soilquality. This results in land degradation because ofusing chemical fertilizersFred, 1991). The chemicalfertilizers used must slather both pests and otherbeneficialorganismsthatcontributehighvaluefunctionsinagriculturalareas(Preap,2009).Thesamementiononthe lossofbothpestsandotherbeneficialorganisms isalsomentionedby(Richard,2010.)

2. A BRIEFDESCRIPTIONOFBIOFERTILIZERSANDBIOPESTICIDES

Biofertilizers are actually the compound that enrichesthenutrientqualityofthesoilbyusingmicroorganismsthatestablishessymbioticrelationshipswith theplants.Biofertilizers may also be defined as microbialinoculants which are artificially multiplied cultures ofcertain soil microorganisms that can improve soilfertilityandcropproductivity.Biofertilizersarelowcostrenewablesourcesofplantnutrientswhichsupplementchemical fertilizers. Biofertilizers generate plantnutrients like nitrogen and phosphorous through theiractivities in the soil or rhizosphere and makes themavailable to the plants on the soil. Biofertilizers aregaining an importance in use because of the propermaintainance of soil health, minimize environmentalpollutionsandcutdowntheuseofchemicals.Thetermbiofertilizer is stillunclear.Thereforebiofertilizersmaybe defined as substances which contain livingmicroorganismswhichcolonizes therhizosphereor theinterioroftheplantsandpromotesgrowthbyincreasingthe supply or availability of primary nutrients to thetargetcropswhentheyareappliedtosoilsseedsorplantsurfaces. Biofertilizers have an ability to mobilizenutritionally important elements from non usable tousable form. These microorganisms require organicmatter for theirgrowthandactivity in soil andprovidevaluablenutrientstotheplant.Biofertilizersarereadytouse live formulates of beneficialmicroorganismswhichon application to seed, root or soil mobilize theavailability of nutrients by their biological activity inparticularandhelpinbuildingupthemicrofloraandinturnthesoilhealthingeneral(Rajendraetal.,1998).

2.1Mechanismofactionofbiofertilizers

1) Biofertilisersfixatmosphericnitrogeninthesoilandandrootnodulesof legumecropsandmakesthemavailabletotheplants.

2) They solubilise the insoluble forms of phosphateliketricalcium,iron,andalmuniumphosphatesintoavailableforms.

3) Theyscavengephosphatesfromsoillayers.4) Theyproducehormonesandanti‐metaboliteswhich

promoterootgrowth.5) They decompose organic matter and help in

mineralizationofsoil.6) Whenthesebiofertilisersareappliedtothesoilsor

seeds biofertilisers increase the availability of thenutrients and improves the yield by 10% to 20%without adversely affecting the soil andenvironment.

Biopesticides are certain types of pesticides derivedfromsuchnaturalmaterialsasanimals,plants,bacteria,andcertainminerals.Biopesticidesmayalsobedefinedas biochemical pesticides that are naturally occurringsubstances that control pests by nontoxicmechanisms.Biopesticidesare livingorganisms (natural enemies)ortheir products (phytochemicals, microbial products) orbyproducts(semiochemicals)whichcanbeusedforthemanagement of pests that are injurious to plants.Biopesticideshaveanimportantroleincropprotection,although most commonly in combination with other




tools including chemical pesticides as part of Bio‐intensive IntegratedPestManagement .Biopesticidesorbiologicalpesticidesposelessthreattotheenvironmentortothehealthofthehumansbecausetheyaretargetedto specifically a single pathogenic pest. These includebiofungicides (Trichoderma), bioherbicides(Phytopthora) and bioinsecticides (Bacillusthuringiensis). The potential benefits to agriculture andpublic health programmes through the use ofbiopesticides are considerable. The interest inbiopesticidesisbasedontheadvantagesassociatedwithsuchproductswhichare:1) inherently less harmful and less environmentalload;2) designed to affect only one specific pest or, insomecases,afewtargetorganisms,3) ofteneffectiveinverysmallquantitiesandoftendecomposequickly,therebyresultinginlowerexposuresandlargelyavoidingthepollutionproblems,4) When used as a component of Integrated PestManagement (IPM) programs, biopesticides cancontributegreatly.3. DIFFERENTTYPESOFBIOFERTILIZERSAND

THEIRCHARACTERISTICFEATURES

Rhyzobium (RHZ) These inoculants are known fortheirabilitytofixatmosphericnitrogeninassociationwith plants forming nodules in roots (stem nodules insesabaniamrostrata). RHZ are however limited by theirspecificity andonly certain legumes are benefited fromthis symbiosis. They belongs to family Rhizobiaceae,symbiotic in nature, fix nitrogen 50‐100 kg/ ha inassociation with legumes only. It is useful for pulselegumes likechickpea,red‐gram,pea, lentil,blackgram,etc., oil‐seed legumes like soybean and groundnut andforage legumes like berseem and lucerne. Successfulnodulation of leguminous crops by Rhizobium largelydepends on the availability of compatible strain for aparticular legume. It colonizes the roots of specificlegumestoformtumorlikegrowthscalledrootnodules,which acts as factories of ammonia production.Rhizobium has ability to fix atmospheric nitrogen insymbiotic association with legumes and certain non‐legumes like Parasponia. Rhizobium population in thesoildependsonthepresenceoflegumecropsinthefield.In absence of legumes, the population decreases.ArtificialseedinoculationisoftenneededtorestorethepopulationofeffectivestrainsoftheRhizobiumneartherhizospheretohastenN‐fixation.EachlegumerequiresaspecificspeciesofRhozobiumtoformeffectivenodules(MishraD.Jetal,2012).

Plant Growth‐Promoting Rhizobacteria (PGPR) –These are naturally occurring soil bacteria thataggressively colonize plant roots and benefit plants byprovidinggrowthpromotion.PGPRareassociatedwithplant roots and augment plant productivity andimmunity; however, recent work by several groupsshows that PGPR also elicit so‐called ‘induced systemictolerance’tosaltanddrought.PGPRmightalsoincreasenutrient uptake from soils, thus reducing the need forfertilizers and preventing the accumulation of nitratesandphosphatesinagriculturalsoils.Scientificresearches

involve multidisciplinary approaches to understandadaptation of PGPR, effects on plant physiology andgrowth, inducedsystemicresistance,biocontrolofplantpathogens, bio fertilization, and potential greenalternative for plant productivity, viability of coinoculating, plant microorganism interactions, andmechanisms of root colonization. Root colonizingbacteria like,Azospirillum,andPseudomonasspeciesareknown to produce growth hormoneswhich often leadsto increase root and shoot growth. Plants differ in theleavesandrationofthehormonesrequiredtomaintainnormal growth and development. Industrial productionof inorganic fertilizers a costly process dependent onenergyderivedfromfossilfuel,whichisgettingdepletedat a faster rate. On the contrary use of microbialinoculants is not only a low cost technology but alsotakes adequate care of soil health and environmentalsafety. Intensive search a number of microorganismshavebeenrecognizedasnitrogenfixers.Thisisnodoubtalowcosttechnologycapableofbringingrich‐dividendstothefarmers.However,transferringatechnologytothefarmers’fieldisofparamountimportance.Generallytheeffectofbiofertilizersoncropgrowthandyieldisnotasstickingasthatofchemicalfertilizers.Sinceitisalivingsystem and the influence is subject to environmental,biologicalandnutritionalstresses.

Azospirillum: belongs to family Spirilaceae,heterotrophic and associative in nature. In addition totheir nitrogen fixing ability of about 20‐40 kg/ha, theyalso produce growth regulating substances. Althoughthere are many species under this genus like,A.amazonense, A.halopraeferens, A.brasilense, but,worldwidedistributionandbenefitsof inoculationhavebeen proved mainly with the A.lipoferum andA.brasilense.TheAzospirillumformassociativesymbiosiswithmanyplantsparticularlywiththosehavingtheC4‐dicarboxyliac path way of photosynthesis (Hatch andSlack pathway), because they grow and fix nitrogen onsaltsoforganicacidssuchasmalic,asparticacid.Thusitismainlyrecommended formaize, sugarcane, sorghum,pearlmilletetc.TheAzotobactercolonizingtherootsnotonly remains on the root surface but also a sizableproportionof thempenetrates intotheroot tissuesandlivesinharmonywiththeplants.Theydonot,however,produceanyvisiblenodulesoroutgrowthonroottissue.

Azotobacter: belongs to family Azotobacteriaceae,aerobic, free living, and heterotrophic in nature.AzotobactersarepresentinneutraloralkalinesoilsandA.chroococcumis themostcommonlyoccurringspeciesinarablesoils.A.vinelandii,A.beijerinckii,A.insignisandA. macrocytogenes are other reported species. ThenumberofAzotobacterrarelyexceedsof104to105g‐1of soil due to lack of organic matter and presence ofantagonistic microorganisms in soil. The bacteriumproduces anti‐fungal antibiotics which inhibits thegrowth of several pathogenic fungi in the root regionthereby preventing seedling mortality to a certainextent.ThepopulationofAzotobacterisgenerallylowinthe rhizosphere of the crop plants and in uncultivatedsoils.Theoccurrenceofthisorganismhasbeenreportedfromtherhizosphereofanumberofcropplantssuchasrice,maize, sugarcane, bajra, vegetables and plantationcropswhichthefungalpartnerisbenefitedbyobtaining




itscarbonrequirements fromthephotosynthatesof thehost and the host in turn is benefited by obtaining themuch needed nutrients especially phosphorus, calcium,copper, zincetc.,whichareotherwise inaccessible to it,withthehelpofthefineabsorbinghyphaeofthefungus.These fungiareassociatedwithmajorityofagriculturalcrops, except with those crops/plants belonging tofamilies of Chenopodiaceae, Amaranthaceae,Caryophyllaceae, Polygonaceae, Brassicaceae,Commelinaceae,JuncaceaeandCyperaceae.

Zinc solubilizers: The nitrogen fixers like Rhizobium,Azospirillum, Azotobacter, BGA and Phosphatesolubilizing bacteria like B.magaterium, Pseudomonasstriata,andphosphatemobilizingMycorrhizahavebeenwidelyacceptedasbio‐fertilizers.Howeverthesesupplyonly major nutrients but a host of microorganism thatcan transformmicronutrients are there in soil that canbe used as bio‐fertilizers to supplymicronutrients likezinc, iron, copper etc.,The zinc can be solubilized bymicroorganisms viz., B. subtilis, Thiobacillus thioxidansand Saccharomyces sp. These microorganisms can beused as bio‐fertilizers for solubilization of fixedmicronutrients like zinc.The resultshave shown that aBacillussp.(Znsolubilizingbacteria)canbeusedasbio‐fertilizer forzincor in soilswherenativezinc ishigheror in conjunction with insoluble cheaper zinccompounds like zinc oxide (ZnO), zinc carbonate(ZnCO3) and zinc sulphide (ZnS) instead of costly zincsulphate.

BlueGreenAlgae (Cyanobacteria)andAzolla:Thesebelongs to eight different families, phototrophic innature and produce Auxin, Indole acetic acid andGibberllic acid, fix 20‐30 kg N/ha in submerged ricefieldsastheyareabundantinpaddy,soalsoreferredas„paddyorganisms‟.N is thekey input required in largequantities for low land riceproduction. SoilN andBNFbyassociatedorganismsaremajorsourcesofNfor lowland rice4. The 50‐60% N requirement is met throughthecombinationofmineralizationof soilorganicNandBNFbyfreelivingandriceplantassociatedbacteria.Toachieve food security through sustainable agriculture,therequirementforfixednitrogenmustbeincreasinglymet byBNF rather than by industrial nitrogen fixation.BGA forms symbiotic association capable of fixingnitrogen with fungi, liverworts, ferns and floweringplants, but themost commonsymbiotic associationhasbeen found between a free floating aquatic fern, theAzollaandAnabaenaazollae(BGA).Azollacontains4‐5%Nondrybasisand0.2‐0.4%onwetbasisandcanbethepotentialsourceoforganicmanureandnitrogen inriceproduction. The important factor in using Azolla asbiofertilizer for rice crop is its quick decomposition inthe soil and efficient availability of its nitrogen to riceplants. Besides N‐fixation, these biofertilizers orbiomanuresalso contribute significant amountsofP,K,S,Zn,Fe,Mbandothermicronutrient.The fern formsagreen mat over water with a branched stem, deeplybilobed leaves and roots. The dorsal fleshy lobe of theleafcontainsthealgalsymbiontwithinthecentralcavity.Azollacanbeappliedasgreenmanurebyincorporatingin the fields prior to rice planting. The most commonspeciesoccurringinIndia isA.pinnataandsamecanbepropagatedoncommercialscalebyvegetativemeans.It

mayyieldonaverageabout1.5kgpersquaremeterinaweek. India has recently introduced some species ofAzolla for their large biomass production, which areA.caroliniana.

Phosphatesolubilizers:Severalreportshaveexaminedthe ability of different bacterial species to solubilizeinsoluble inorganic phosphate compounds, such astricalcium phosphate, dicalcium phosphate,hydroxyapatite, and rock phosphate. Among thebacterial genera with this capacity are pseudomonas,Bacillus, Rhizobium, Burkholderia, Achromobacter,Agrobacterium, Microccocus, Aereobacter, Aspergillus,Flavobacterium and Erwinia. There are considerablepopulationsofphosphatesolubilizingbacteriainsoilandin plant rhizospheres. These include both aerobic andanaerobicstrains,withaprevalenceofaerobicstrainsinsubmergedsoils.Aconsiderablyhigherconcentrationofphosphate solubilizing bacteria is commonly found inthe rhizosphere in comparison with non rhizospheresoil. The soil bacteria belonging to the generaPseudomonasandBacillusandFungiaremorecommon.

Phosphate absorbers (Mycorrhiza): The termMycorrhiza denotes “fungus roots”. It is a symbioticassociation between host plants and certain group offungi at the root system, in land salinity/alkalineaffected5.Therefore,theinoculationswithPSBandotheruseful microbial inoculants in these soils becomemandatory to restore and maintain the effectivemicrobial populations for solubilization of chemicallyfixed phosphorus and availability of other macro andmicronutrients to harvest good sustainable yield ofvarious crops. 18( Role of Bio‐Fertilizer in OrganicAgriculture: A Review by Mishra D.J., Singh Rajvir,MishraU.K.andShahiSudhirKumar).

4. DIFFERENT TYPES OF BIOPESTICIDES ANDTHEIRCHARACTERISTICFEATURES

Microbial pesticides‐ These contain a microorganism(bacterium, fungus, virus, protozoan or alga) as theactiveingredient.Microbialpesticidescancontrolmanydifferent kinds of pests, although each separate activeingredient isrelativelyspecific for itstargetpest[s].Forexample,therearefungithatcontrolcertainweeds,andother fungi that kill specific insects. The most widelyknown microbial pesticides are varieties of thebacteriumBacillusthuringiensis,orBt,whichcancontrolcertain insects in cabbage, potato, and other crops. Btproducesaproteinthatisharmfultospecificinsectpest.Certainothermicrobialpesticidesactbyout‐competingpest organisms. Microbial pesticides need to becontinuously monitored to ensure that they do notbecome capable of harming non‐target organisms,including humans. PIPs are pesticidal substances thatplants produce from genetic material that has beenadded to theplant. Forexample, scientists can take thegenefortheBtpesticidalprotein,andintroducethegeneinto the plants own genetic material. Then the plant,insteadof theBtbacteriummanufacturesthesubstancethat destroys the pest. Both the protein and its geneticmaterial are regulated by EPA; the plant itself is notregulated.Biochemicalpesticides‐ Thesearenaturallyoccurringsubstances such as plant extracts, fatty acids or




pheromones that control pests by non‐toxicmechanisms. Conventional pesticides, by contrast, aresynthetic materials that usually kill or inactivate thepest. Biochemical pesticides include substances thatinterfere with growth or mating, such as plant growthregulators,orsubstancesthatrepelorattractpests,suchas pheromones. Because it is sometimes difficult todeterminewhetheranaturalpesticidecontrolsthepestby a non‐toxic mode of action, EPA has established acommittee to determinewhether a pesticidemeets thecriteriaforabiochemicalpesticide.5. ROLE OF BIOFERTILIZERS IN INCREASING

THEPRODUCTIVITYOFTEAANDREDUCINGTHEUSEOFCHEMICALFERTILIZERS

Ithasbeenfoundandalsoobservedthatwiththeadventof chemical fertilizers and the excessive use of thesechemical fertilizers to gain a maximum output hasfinally lead to the immense adverse effects onenvironment.Theadverseeffectofhighdoseoffertilizersoncrop(Sahaetal.,2000;)andsoil(VanHerwaardenetal., 1998 ;) evident in later years. Even, in agriculturalsector,inorganicfertilizershavealreadybeentermedasoneofthemostimportantagentsforcausingpollutiontosoil and water (Prakasa Rao and Puttanna, 2000).Application of inorganic fertilizers even at balancedamountdidnotsustainthesoilfertilityandproductivityunder continuous cropping (Kumpawat, 2004). Theimpact of such high dose of fertilizers on growth andyieldofteawaswelldocumentedbymanyauthors(DevChaudhuryetal.,1983)b).Environmentalpollutionandresidueleftoverbychemicalsappliedonsoilaregainingdue importance and looked into seriously in tea(Barooah,2005)asteaisalsoaforeignexchangeearnerand has to face intrinsic network of tests of differentcertifying agencies. Tea is likely to be a perennial cropand so it does not have the advantage of gainingnutrients from the residues of previous crops throughthesystemofcroprotation.Thereforetheteaplantsaregrown under the leguminous shade trees, and thereremains a weed flora on the soil which provides thenutrientsandaddsvegetativenutrientstothegroundstonourish the tea plants. Shade trees drop leaves, twigs,pods, dry branches etc (Dutta, 1960; Visser, 1961,Barua,1989,Vermaetal.,2001)andweedsprovidedeadanddecayedmaterials(Ranganathanetal.,1980)toteasoil,whichhelpsinaddingtheamountoforganicmatterand nutrients to tea soil from different sources likeshade trees, pruning litters, weeds etcwere available,but a holistic approach to conservation of all thesematerials,estimationsontotalgainsandlossesthroughnatural processes in field condition and a look intopossibilities of reducing fertilizers in lieuof additionoftheabovematerialswerelacking.

On the other hand the applications of variousbiofertilizersaregainingpopularityinplantnutritionofother crops. Rhizobium (D. N. Saikia et al, 2011),Azotobacter and diazotrophicus, (Cavalcante andDobereiner, 1988), Azospirillum (Fages, 1994), PGPR(Kloepper et al., 1980), VAM (Misra, 1997, Borthakur,2001) etc. had been reported to be useful in nutrientmanagementofcropstoincreaseyield.

Under these conditions where tea plants needs to beprotectedestimationwasmadeonthegainofnutrientsthrough the addition of shade tree droppings, pruninglitters cheeled weeds etc. The observations wererecordedwheretheteaplantsweredividedinfourplotsand the shaded tree droppings, fallen leaves on theground andweed biomasswere collected from time totime and then added to the soil. Similarly the pruninglitters were also colleceted chopped and added to theplots where the tea plants were planted. Weeds werecollected from time to time and added to thesoil.Annalysis wasmade for all these samples for theirNPK content and field records were done throughweeklyplucking

Inanotherpartestimationwasalsomadetoensuretherationalizationofnutrientapplicationinteathroughtheconservationof the available biomass and reducing theinorganic fertilizer. The estimation was made by anexperiment which was done in RBD design with threereplications and each plot consisted of 200 plants. Theexperimentwastakenup inordertosee ifreduction inapplicationofinorganicNfertilizercouldbemanagedbyretainingallavailablebio‐massinthatparticularsection.

In a third part the introduction of biofertilizers weredone to increase theproductivityof teaplantsandalsotoreducetheapplicationofinorganicfertilizers.AnRBDdesignwasformulatedwithseventreatmentsandthreereplicationswherethetea–plantswereplantedinplotsduringJune,2009,andallowedtogrowandtippedat70cm fromground.Plantswereagainprunedduring laterpartofJanuary,20I0,at35cmfromgroundandtippedat70cm.

The treatment and conservation of biomass for thesecondexperimentcanbeunderstoodbythetreatmentdetails where T1 had control (No biomass) + NPK @130:30:130,T2hadAvailablebiomass+NPK@130:30:130,T3hadAvailablebiomass+20%reductioninNinNPK,T4hadAvailablebiomass+30%reductioninninnpk, T5 had Available biomass + Quick decomposer(Fusarium+Aspergillus+Trichoderma@5%each)

In the third experiment the treatment combinationswere T1,= Control, T2= 30g each of RP and SSP inplanting hole before planting +YTD at usual dose andintervalasperrecommendation,T3=25%ofbothbasalandYTDfertilizers,Kat100%+Bioconsortium,T4=50%of both basal and YTD fertilizers, K at 100%+Bioconsortium ,T5= 75% of both basal and YTDfertilizers,Kat100%+.Bioconsortium,T6=SoilwithRPandSSP+Bioconsortium,T7=Onlysoil+Bioconsortium.The bioconsortium had biofertilizers like Azospirillum,PSB,Trichoderma,AMF.

In the result it was found that in the Light Prunningyearslitterwasfoundtovaryfrom3598kg/hato3980kg/ha with an average of 3769 kg/ha. In DS it rangedfroml411kg/ha to1375kg/hawith an averageof1398kg/ha.2007wasanUPyear.

Shade trees provided 558,707 and 716 kg ofmaterialsliketwigs,pods,decayedbranchesetc.intheyear2005,2006 and 2007 respectively. In this three‐year pruningcycle(LP‐DS‐UP),ashighas5167kgpruninglitterswas




available. . In the UP year there was 670 kg of fallenleavesthatincreasedto743kg/hainDSand1078kg/hainLP.Atotalof2491kg/hawasreceivedinthepruningcycle.

Itwasalsoobservedthattheactiveperiodoftealeaveswas about six months after which the tea plants shedleavestotheground.WorkinginSouthIndia,32Vermaetal.(2001)reportedthatnearly57kgN/hawasrecycledto tea soil through addition of 2708 kglha foliage fromthe shade trees of Gravillearobusta. Weed contributedonly 230 kglha in UP year while in LP it rose to 1087kglhawithatotalof2208kglhainthepruningcycle.Inamass whencalculated togetherallof themcontributedtoatotalof6492kgofbiomass/hainLP,3739kg/hainDS, and 1616 kg/ha in UP. The grand total came upto12025 kg/ha of biomass added to the soil in pruningcycle.ThevariationcanbefoundinTable1.

Table‐1Yearwiseadditionofbiomass(kg/ha)togroundundertea

COMPONENTS 2005 2006 2007 TOTAL MEAN

FertilizerNPK 100‐20‐100

100‐20‐100

100‐20‐100

100‐20‐100

100‐20‐100

Prunninglitters

3769 1398 0 5167 1722

Shade treedrops

558 707 716 1981 660

Fallenleaves 1078 743 670 2491 830

Weeds 1087 891 230 2208 736

Total 6492 3739 1616 11847 3949

(Sustainableproductivityofteathroughconservationofbio‐mass, addition of bio‐fertilizers and reduction ofinorganicfertilizerbyD.N.Saikia1;J.Sarma;P.K.DuttaandD.K.Baruah,2011)

Inthesecondexperimentthetotalbio‐massrecordedinpruning year and the yield data recorded which wasfoundin2008,2009and2010insecondexperimentaregiven in Table (2) below. It can be observed from theTable2thattherewasnosignificantvariationbetweenthe available bio‐mass in the plots where the averagebio‐masswasrecorded3298kg/ha.Inthefirstyearthatis in 2008 themain effect of treatment on yield of teawas not very significant. The yield however tended toincreaseintreatedplotscomparedtocontrol.Themaineffect of the treatment on yield of teawas found to besignificant (pd"0.05) in 2009. All the treatments werefound to increase crop significantly over control butbetweenthemtherewasnodifference.In2010also,theeffect of treatmentwas significant (pd"0.05) andT2,,T1andT5werefoundtoincreasethecropovercontrol.TheyieldwasfoundtoreduceatT4i.e.whenfertilizerswerereducedby30%andwasatparwiththecontrolwherefertilizerswerenotapplied..(D.N.Saikiaetal,2011).

Table‐2:TotalBiomassandEffectofTreatmentsontheYieldsofTea.

Treat

MeanBiomass

Yield(KMTH)

2008(LP)

Yield(KMTH)

2009(UP)

Yield(KMTH)

2010DS

MeanYield(KMTH)

T1 2197 2113 1711 2007

T2 3150 2346 2330 1808 2161

T3 3227 2331 2329 1810 2157

T4 3390 2248 2323 1725 2099

T5 3424 2481 2423 1839 2248

519.64 Ns 206.75 77.0


In the third experiment the effect of biofertilizers onpruninglitterswerenotedandgiveninTABLEformat3.Allthetreatmentsincreasedpruninglittersovercontrol.Maximum pruning litter was found in T6 treatmentwhere bio‐consortium was added with standardpractice.Bio‐consortiumshowedminimumimpactwhenappliedwith controlwithoutRP/SSP.The effect of bio‐consortium on yield of young tea was found to besignificant (pd" 0.01). All the treatments increased theyield over control. Although bi‐consortium treatmentsT4, T5 and T6 showed increasing yield over T2 i.e.standardpractice,onlyT5with75%offertilizeri.ewith25% reduction from standard practice showedsignificant increase. Bio‐ consortium with only 25% ofthe fertilizer orwith only soil showedminimum effect.Thus, it appears that with addition ofbio‐fertilizers inyoung tea about 25% reduction of recommendedfertilizers may be possible. Boddey et al. (1988)estimated from pot and field studies that contributionfrom BNF in sugarcane could be 5‐60 kg N/ha/yr.35MertensandHess(1984)alsoreportedsignificantyieldincrease inwheat (10‐40%) above controlmainlywithintermediate rates ofN‐fertilizer by inoculation withAzospirillum.

Table3:EffectofBiofertilizeronPrunningLitters

Treatment Prunninglitters

Yield

TI=Control 35.59 302.79

T2=30 g RP and SSP inplantingpit+YTD

73.86 422.30

T3=25% of both basal andYTDfertilizers

58.52 387.29




+100%K+Bio‐consortium

T4=50"10of both basal andYTDfertilizers

+IOO%K+Bio‐consortium

66.53 446.33

T5=75% of both basal andYTDfertilizers

+100%K+Bio‐consortium

66.79 459.11

T6= Soil with RP and SSP+Bio‐consortlUm

96.64 420.47

T7=Only soil + Bio‐consortium

40.36 339.00


Finally it can be concluded that the conservation ofavailablebiomass in teasectionsprovidedhighamountoforganicmatterthataddedgoodamountofnutrienttothesoil.Pruninglitterssinglyprovided75kg/haN,16kgP2o5and26kgK2o/ha.Fallenleavesandweedsalsoalsoprovided good nutrient supply. 20% reduction ofnitrogen fertilizer was possible. Finally application ofbiofertilizerconsortiumhelpedinreducing25%doseofYTDmanure.

6. INCREASE IN PRODUCTIVITY OF RICETHROUGHTHEINRODUCTIONOFNITROGENFIXING BACTERIA AND PHOSPHATESOLUBILISING BACTERIA ASBIOFERTILIZERS

The Nitrogen fixing bacteria Azospirillum were themajor attractions as biofertilizerswhich could increasethe productivity of rice and help in their propercommercial exploration. Nitrogen fixing bacterias arecapable of fixing atmospheric nitrogen and P‐solubilizing microbes solubilize phosphate into solubleform.

InaRandomizedBlockDesignpatternofstudywithtentreatmentsandthreereplicationswherethetreatmentsconsisted of T1=Control, T2=Biofertilizers, T3=RDF,T4=RDF+ biofertilizers (Azospirillum andphosphobacterin), T5=RDF +ZnSO4@ 25 kgha‐1,T6=RDF + biofertilizers + ZnSO4 @25 kgha‐1, T7=150per cent RDF, T8=150 per cent RDF + Biofertilizers,T9=150 per cent RDF + ZnSO4 @ 25 kgha‐1andT10=150 per cent RDF + ZnSO4 @ 25 kgha‐1+Biofertilizers. One month old seedlings weretransplanted in themain fieldwith2 seedlingsperhill.Beforetransplanting,seedlingsofrespectivetreatmentswere inoculated with biofertilizer slurry. A fertilizerdose of 75:75:90 kg N, P2O5 and K2O ha‐1 (RDF) and150 per cent RDF was applied in two split doses.Fertilizers were applied in the form of urea,diammonium phosphate and muriate of potash andZnSO4 @ 25 kgha‐1was applied in the respectivetreatments.

IntheresultsofthesetreatmentsshowedthatT10whichreceived 150 per cent RDF, biofertilizers and ZnSO4@25 kg ha‐1 recorded the highest value for all yieldcomponentssuchasnumberofproductivetillersperhill(16.1), mean panicle length (25.7 cm), mean panicleweight(3.5g),numberofgrainsperpanicle(148.0)andtestweight(30.1).TreatmentT1(control)recordedthelowest value for all yield components. Number ofproductive tillersperhill, numberof grainsperpanicleandtestweightintreatmentT10wasonparwithT9,T6,T8andT7andwassignificantlysuperioroverallothertreatments.35 Kumari et al (2000) suggested that theproductive tillers had significantly increased with theincreased levels of nitrogen upto 120kg/ha . The totalandfilledgrainsperpanicleandgrainweight increasedwithincreaseinnutrientapplication.Itcanbeestimatedthat the increase in yield is due to the inoculation ofAzospirillum which is capable of fixing nitrogen andmaking it available to the crop throughout the cropperiod.

In the case of grain and straw yield, T10 recorded thehighest value (111.2 q ha‐1 and 127.6 q ha‐1) and T1recordedlowestvalue(45.3and49.5qha).T10wasonparwithT9andT6andwassignificantlysuperioroverall other treatments. Harvest index of the experimentsranged from 0.47 to 0.49. There was no significantvariation in harvest index of rice due to nutrient andbiofertilizers. The higher yield in T10 was due to thehigher magnitude of yield components. Kumari et al.(2000)reportedthatnitrogenlevelincreasedfrom40to120kgha‐1brought about significant increase ingrainyieldovercontrol. Thegrainyield, strawyieldand theharvestindexhasbeenstatedinTable‐4.

Table4:Effectofnutrientsandbiofertilizersongrainyield,strawyieldandharvestindex

Treatments Grainyield

Strawyield

Harvestindex

T1Control 45.3 49.5 0.47

T2Biofertilizers

57.1 59.7 0.48

T3 RDF 84.0 88.3 0.49

T4 RDF +Biofertilizers

88.4 90.0 0.49

T 5 RDF +ZnSO4 25kg/ha

92.3 96.0 0.49

T6RDF+ZnSO425 kg/ha +Biofertilizers

102.5 117.4 0.47

T7150%RDF 97.4 101.9 0.49

T8150%RDF +Biofertilizers

99.3 104.3 0.48

T9150%RDF+ZnSO4 25

107.7 123.3 0.47




kg/ha

T10150% RDF+ ZnSO4 25kg/ha +Biofertilizers

111.2 127.6 0.47

S.em 3.6 3.4 0.2

CD 10.6 10.0 NS

(EffectofNutrientsandBiofertilizersonYieldandYieldComponentsofRiceinCoastalAlluvialSoilofKarnataka*byDHANYAV.MATHEWS,P.L.PATILANDG.S.DASOG).

The increase in yield is due to the inoculations withbiofertilizerswhichmightnotbesolelyduetonitrogenfixation or phosphate solubilization, but because ofseveral other factors such as release of growthpromoting substances, control of plant pathogens,proliferationofbeneficialorganismsintherhizosphere.These findings were in accordance with (Tein et al.(1979)and(KunduandGauretal(1984).((DHANYAV.MATHEWS,etal,2006).

7. POTENTIAL ROLE OF AZOLLA ANDANABAENA AS BIOFERTILIZERS TOINCREASETHEPRODUCTIVITYOFRICE

Apart from India where the use of biofertilizers hassignificantly increased as seen above, the use ofbiofertilizerhasalsosignificantlyincreasedinEuropeancountrieslikeItaly,GermanyandotherNordiccountries.

Azolla is a heterosporous pteridophyte, with sevenspecies. It contains, as endosymbiont,AnabaenaazollaeStrasburger, a nitrogen fixing cyanobacterium(Nostocaceae family). Available bibliographical data onitsenvironmentaldevelopmentareprincipallyrelatedtoexperimentscarriedoutinAsiancountries(D.T.Tuanetal,1979)

Riceyieldsdeclinewithtime,( J.K.Ladha etal ,2000.),in long‐term experiments carried out in a rice‐riceintensive system under tropical conditions, and this isrelated by the authors to the decrease of thephysiologicalN use efficiency. Long‐termeffects of ureaand greenmanure on rice yield and nitrogen balancewerealsoverifiedintemperateconditions(D.Casanova,et al, 2002.) Where the nitrogen use efficiency (NUE)was particularly low It is particularly important toincreasetheefficiencyofnitrogenuseandconcomitantlyto reduce water pollution, by changing strategies ofmineraluseandby integratingorganic fertilizers in thericeproductionsystem.

Therefore under temperate climatic conditions andenvironment, different Azolla strains, were chosen oncomparisonbasisandonthebasisoftheirresistancetolow temperatures, (b) analysing the spring growth rateof the most resistant one, (c) determining theconcentrationofNintheAzollabeforethesowingofriceto evaluate it as ricebiofertilizer, and (d) assessing themorphological modification of Azolla in response totreatments with three kinds of commonly usedherbicides.

The four BGC strains were compared with another(“Milan”)whichhadpreviouslyaclimatized,overseveralyears, to the environmental conditions of the Milan‐PaviaprovinceinItaly,locatedintheEuropeanRiceBelt(latitude 45◦N). Thewinter experiment, carried out toevaluatecoldresistancethroughgrowthanalysisofthe5strains,startedonDec.6th2000,approximately50daysafterthearrivalofthenewstrains.

Intheresultsitwasfoundthatallthestrainswithlowwinter temperature resistance ,had a progressivedecrease in leaf dimensions , associated withaccumulationofanthocyanins.Induecourseoftime,theJapan and Italy strains assumed a tawny colour (anindicator of drying preceding death). After 126 daysfrom the beginning of the experiment, on the Apr. 11th2001, these strains were eliminated from theexperiment. By April, the leaf dimensions of theremaining strains were comparable to those at theoutset of the experiment, with the leaves of the Milanstrain bigger than those of the Sweden and Germanystrains.CarbonandNitrogencontent,andC/Nratios inAzolla strains. It was observed that high quantities ofnitrogenintheleafoftheJapanandItalystrains,whichappeared to be related to the decrease of its biomassduringthetest.TheMilanstrainshowedlowernitrogencontent,butagoodC/NratioassociatedwithahighRGR.

Inanotherpart,themeantemperaturesandRH%duringthecourseoftheexperimentshowedthatAzollabiomasshas increased whichmeans that thay are somewhatdependent on air humidity, as at less than 60%relativehumidity, the fern becomes dehydrated andfragile.During the experiment, the RH% dipped belowthis critical level for a brief period. The growth ratemeasurements are important in the estimation of theamountofAzollarequiredto inoculatericepaddiesandtoprovide a sufficient nitrogen contribution (25–30Kgha−1).

In a third part of herbicide treatments analysis of thenitrogen and carbon content show that significantdifferencesbetween treatmentswerenoticeable for thenitrogen and carbon contents,while differences in C/Nratios are less marked. Herbicide treatments generallycausedstress,withanassociatedfallinNandCcontentuntildeathensued.Treatmentswith6L/haofPropaniland Oxadiazon were, from the outset, deleterious fornitrogen and carbon accumulation. reatment with 200g/haofCinosulfuroninitiallycausednochangeoronlyaslight increase in nitrogen and carbon content. At 13days, the fresh weight of the samples treated withCinosulfuron had shown slight increase of biomass inrespect to initial inoculum. However, after thisintermediate phase, Cinosulfuron caused a progressivedeterioration leading to the death of the fern. OnlyPropanil 6Lha−1 treatment allowed 60% of plants tosurvive,albeitwithreducedquantitiesofnitrogenfixed.

Finally it can be concluded that although the 4 strainsare all recognized as cold resistant, adapted tocontinental climates or to cold winters, the resultsindicated that only the Milan strain is likely to becapableofsurvivingNorthern




Italianwinterconditions.TheMilanstrainwasthereforeused inaherbicideresistancestudyandthat theuseofAzollainPoValleyconditionshasapotentialtobeusedasabiofertilizer.

8. THE CURRENT STATUS OF BIOFERTILIZERININDIA

Thefertilizerconsumptionvariesfrom130,125,60and70 kg Hect (NPK) for north, south, west and eastrespectivelymakingforanationalaverageofapprox.90kg/Hect. Some states like Punjab are using more than167kgnutrientsperhectareasagainstsomeusing lessthan10kgnutrientsperhectare.Eventhefullpotentialof available technologies is not fully utilizeddue to thefactthatnutrient inputdoesn'tmatchtheneedsofcrop

and soil. In case of biofertilizers the production andsupply ofmicrobial cultures, the qualityof the culturesandthelackofpublicityareaffectingtheirpopularityasnutrient sources. The government has no control overmanufactures of biofertilizers for any of the state ofIndia.OnlyafewentrepreneurspossesISImarkfortheirproducts and most of the products are of substandardquality. Due to these laxities on the part of Govt. thefarmers are confused about their rates, availability andexpiry dates. The necessary action by government anditspolicieswillcertainlygotoa longwayinthefurtherdevelopment of the biofertilizers.( S. Rajasekaran et al2012,)

Table‐5:ChangingCompositionofBiofertilizersinIndia

Year 2004‐2005

2005‐2006 2006‐2007 2007‐2008

2008‐2009

2009‐2010

2010‐2011

Toatal Tonnes%share

1600.01 2914.37 4988.90 6688.32 6681.44 6295.63 6700.3

Rhizobium 57.27 40.50 29.41 21.15 20.84 19.85 18.62

Azotobacter 13.00 22.20 18.47 18.46 15.51 17.30 17.74

Azospirillum 12.54 11.11 14.08 17.99 11.34 10.17 11.77

Nitrogenfixer 82.81 73.80 61.96 57.61 47.69 47.32 48.12

Bga 0.00 0.00 0.06 0.04 0.01 0.02 0.04

Phosphatesolubilizer

17.19 26.20 35.77 40.46 49.88 48.75 48.98

(FERTILIZERASSOCIATIONOFINDIA).(S.Rajasekaran,K. Sankar Ganesh , K. Jayakumar , M. Rajesh , C.Bhaaskaran,P.Sundaramoorthy,Biofertilizers‐CurrentStatus of Indian Agriculture International Journal ofEnvironmentandBioenergy,2012,4(3):176‐195)

9. POTENTIAL ROLE OF BIOPESTICIDES INKILLINGDIFFERENTINSECTS

Biopesticidesrepresentonly2.89%(ason2005)of theoverall pesticide market in India and is expected toexhibit an annual growth rate of about 2.3% in thecoming years . In India, so far only 12 types ofbiopesticideshavebeenregisteredundertheInsecticideAct, 1968. Neem based pesticides,Bacillusthuringensis,NPV and Trichoderma are the major biopesticidesproduced and used in India. Whereas more than 190syntheticsare registered foruseaschemicalpesticides.Mostofthebiopesticidesfinduseinpublichealth,exceptafewthatareusedinagriculture.Besides, i)transgenic

plantsandii)beneficialorganismscalledbio‐agents:areusedforpestmanagementinIndia.

In certain cases of biopesticideswhere the use of theinsect‐pathogenic fungusMetarhiziumanisopliaeagainstadultAedesaegyptiandAedesalbopictusmosquitoeshasalsobeenreported(E.J.Scholte,etal2007).Thelifespanof fungus‐contaminatedmosquitoesofbothspecieswassignificantly reduced compared to uninfectedmosquitoes. The results indicated that both mosquitospecies are highly susceptible to infection with thisentomopathogen.

In another case Entomopathogenic fungi (Hypocreales)have been used for the control of potato psyllid plantsuntilcaterpillarsfell fromtheplantsontocottonsheets.This technique isnowusedtoobtaincaterpillarswhicharefedonvirus‐infectedseeds.Baculoviruspreparationsobtained in thisway are used by farmers to prepare abioinsecticide spray applied on pigeonpea fields.Another baculovirus, HaSNPV is almost identical to




HzSNPV. It was registered in China as a pesticide in1993.It has been used for large scale biopesticideproduction and has been extensively used on cottonfields.BroadspectrumofbiopesticidebasedonHaNPVisalsousedinIndia(M.Srinivasa,etal,2008).

In another case the neem plants have been used asbiopesticides.Neemproductsareeffectiveagainstmorethan350speciesofarthropods,12speciesofnematodes,15 species of fungi, three viruses, two species of snailsand one crustacean species . Azadirachtin, atetranortritarpinoid,isamajoractiveingredientisolatedfrom neem, which is known to disrupt themetamorphosisofinsects.Twotetracyclictriterpenoids‐meliantetyraolenoneandodoratone isolatedfromneemexhibitedinsecticidalactivityagainstAnophelesstephensi. Neem Seed Kernel Extract (NSKE) was found mosteffectiveinreducingthelarvalpopulationofHelicoverpaarmigera in chickpea and pod damage. Neemformulationsalsohaveasignificanteffectagainsteggsofpeach fruit fly Bactrocerazonata(Saunders). Over 195species of insects are affected by neem extracts andinsects that have become resistant to syntheticpesticides are also controlled with these extracts. Theapprehension that large‐scale use of neem basedinsecticidesmayleadtoresistanceamongpests,asbeingobservedwithsyntheticpesticides,hasnotbeenprovedcorrect (S.Bhushan, etal,2011, ).Neembio‐pesticidesaresystemicinnatureandprovidelongtermprotectiontoplantsagainstpests.Pollinatorinsects,beesandotheruseful organisms are not affected by neem basedpesticides(SalmaMazidetal,2011).

10. CONCLUSION

To increase the productivity of agricultural lands andalsotobringabouttheincreaseinyieldoffoodcropstheuse of beneficial microorganisms as biofertilizers hasshownahugeimprovementinrecentyears.Sonowtheuseofchemical fertilizersandchemicalpesticidesmustbe lessened . In this review also the proper use ofbiofertilizersonbothriceandteashowedanincreaseinyield in both cases. Now the time has come for thefarmers to accept this new technology. Council ofAgriculture (COA) held various seminars as well asworkshops on the application of biofertilizers, so thatfarmerswould have the opportunity to understand theeffects of biofertilizers and are willing to use them.Farmers were invited to inspect the growth ofAMF,RhizobialorPSBinoculatedcrops inthe fieldsandwere encouraged to participate in workshops afterviewing the successful outcomes of using biofertilizers.Theapplicationofinorganicchemicalfertilizerswasthussignificantly reduced to 30‐50%. This helps in therealization of environmental friendly and sustainableagriculture.

11. CONFLICTOFINTEREST

Noconflictofinterest.

ACKNOWLEDGEMENT

I am grateful to DR. (Prof) Sudip Kumar Banerjee forgiving me a chance to write a review on biofertilizersandalsoforguidingmeintheentireresearchassociated

to biofertilizers. I am also thankful to Techno IndiaUniversityforgivingmeachancetopursuemyPh.dandforfundingmyproject.

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Documents

A REVIEW ON THE EFFECTS OF BIOFERTILIZERS … REVIEW ON THE EFFECTS OF BIOFERTILIZERS AND BIOPESTICIDES ON RICE AND TEA CULTIVATION AND PRODUCTIVITY DEBOJYOTI ROYCHOWDHURY 1,*, MANIBRATA