G.V.PrasannaKumara,*,H.RaheaDepartmentofAgriculturalEngineering,NorthArunachalPradesh,IndiabAgriculturalandFoodEngineeringDepartment,articleinfoArticlehistory:Received1May2011Receivedinrevisedform2011IAgrE.PublishedbyElsevierLtd.Aductionof129millionmetrictonsandyieldof16.2metrictonshaC01intheyear2008e2009(GovernmentofIndia,2009).About175typesofvegetablesaregrowninIndiaincluding82fieldvegetablesand41root(tuberandbulb)crops(Randhawa,1998；Subramanian,Varadarajan,&Asokan,2000).Mostofthelycopersicum),eggplant(Solanummelongena)andpeppers(Capsicumspp.)arefirstsowninnurserybedsandlatertransplantedmanuallyeitheronridgesoronawellpreparedseedbed(Ghai&Arora,2007).Manualtransplantingofseed-lingsislabour-intensive,expensive,timeconsumingand*Correspondingauthor.Tel.:913602257379；fax:913602258533/2257872.Abiosystemsengineering110(2011)189e197E-mailaddress:(G.V.P.Kumar).1.IntroductionIndiaisthesecondlargestproducerofvegetableswiththevegetableslikecucurbits(Cucurbitaspp.),beans(Phaseolusspp.),okra(Abelmoschusesculentus)andleafyvegetablesaresowndirectlyinthefield.Vegetablesliketomato(Solanumevaluatedfortransplantingtomatoat45C245cmspacinginthefieldataforwardspeedof0.9kmhC01.Fieldcapacityofthetransplanterwasfoundtobe0.026hahC01.Itresultedinthesavingof68%labourand80%timeovertheconventionalmethodofmanualtransplanting.Theplantingrateofthetransplanterwasfoundtobe32potseedlingsminC01with4%missedplantingand5%tiltedplanting.Thesoilcoveringefficiencyofthedevelopedvegetabletransplanterwasabout81%andthequalityoftransplantingwassatisfactory.17July2011Accepted1August2011Publishedonline30August20111537-5110/$eseefrontmatter2011IAgrE.doi:10.1016/j.biosystemseng.2011.08.001manbEasternRegionalInstituteofScienceandTechnology,Nirjuli791109,Itanagar,IndianInstituteofTechnology,Kharagpur721302,WestBengal,IndiaA9.75kWwalk-behindtypehandtractorpowered2-rowfullyautomaticvegetabletransplanterforindividualpaperpotseedlingswasdevelopedbyconsideringthepoweravailability,paperpotdimensionsandspaceavailabilityinthehandtractorafterthecompleteremovalofrotavatortillageassembly.Itconsistedoftwosetsoffeedingconveyor,meteringconveyor,seedlingdroptube,furrowopener,soilcoveringdevice,anautomaticfeedingmechanism,adepthadjustmentwheelandhitchingarrangement.Horizontalslat-typechainconveyorwasusedasfeedingconveyorandhorizontalpushertypechainconveyorwasusedasmeteringconveyor.Theautomaticfeedingmechanism,withatimingshaft,camandclutch,wasusedtocoordinatetheworkingoffeedingandmeteringconveyors.Thevegetabletransplantercarried108seedlingsontwofeedingconveyorsinuprightorientation,fedthemtothemeteringconveyorsandplantedtheminuprightorientationinfurrows.TheperformanceofthevegetabletransplanterwasvegetabletransplanterforpaperpotseedlingsDevelopmentofawalk-behindtypehandtractorpoweredResearchPaperjournalhomepage:www.elseviPublishedbyElsevierL/locate/issn/15375110Allrightsreserved.2.PaperpotseedlingsformechanicaltransplantingPaperpotsseedlingsweregrowninaluminiumtraysinadoublelayerpolyethylene-coveredunheatedgreenhouse.Theready-to-plantpaperpotseedlingoftomato21daysafterseedingandfollowing4daysofhardeningisshowninFig.1.Eachseedlingwasgrowninadoublelayeredcubicalpaperpotof50cm3volumefilledwithvermicompost,soilandsandintheproportionof1:1:1byvolume.Thevolumeofpotandtheproportionofingredientsinthesoil-basedvermicompost-amendedmixweredeterminedbyconductingexperimentsintwodifferentseasons(Kumar&Raheman,2010)andapplyingoptimisationtechniquestothebiomassgrowthdata.Paperpotsattheendofseedlingstagehadwidedimensionalvari-ationsduetonon-uniformwettingofpottingmixandpotwallsduringwateringofseedlingsinpaperpots,non-uniformdryingofpottingmixafterwatering,physicalpressurefromotherneighbouringpotsinthetrayanduncontrolleddryingofpottingmixduringtheseedlinghardeningprocess.Thefinaldimensionsandweightofthepaperpotwithmixarepre-sentedinTable1.theflights(Armstrong&Hanacek,1984；Sakaue,1992；Shaw,biosystemsengineering110(2011)189e197190oftenresultsinnon-uniformplantdistribution(Kumar&Raheman,2008；Manes,Dixit,Sharda,Singh,&Singh,2010；Parish,2005).Tractor-mounted2-rowand3-rowsemi-automaticvege-tabletransplantershavebeendevelopedinIndiaforbare-rootseedlingsandplugs(DARE,2006,pp.109e128；Manesetal.,2010).Pocket-typemeteringdeviceshavebeenprovidedinthetransplantersforbare-rootseedlings.Thefieldcapacityandlabourrequirementhavebeenreportedtobe0.082e0.092hahC01and44.4man-hhaC01respectivelyataforwardspeedof0.8e1.0kmhC01.Rotarycup-typemeteringdeviceshavebeenprovidedinthetransplantersforplugs.Theyhadafieldcapacityof0.14hahC01andlabourrequire-mentof28.6man-hhaC01whenoperatedataforwardspeedof1.4kmhC01.Thequalityoftransplantingwasreportedtobesatisfactoryforboththemachines.FarmersinIndiaallocatearelativelylowproportionoftheirlandforvegetables(Birthal,Joshi,&Thorat,2007).Further,smalllandholdings(lessthan2ha)contributeabout61%ofthetotalvegetableproduction(Kumar,Pal,&Joshi,2004,pp.9e34),buttheycompriseabout78%ofthetotaloperationalholdings(GovernmentofIndia,2002).Insmallholdings,6.75e10.58kWwalk-behindtypehandtractorsratherthanlargertractorsarepopularpowersourcesforcarryingoutdifferentagriculturaloperations(Dewangan&Tewari,2008).Therefore,thereisagenuineneedtodevelopahandtractorpoweredvegetabletransplanterforuseinsmallplotsandsmalllandholdings.Thehandtractor-poweredvegetabletransplanterhastobeafullyautomaticmachineasanoperatorcouldnotsimultaneouslycontrolandmanoeuvrethehandtractorandfeedtheseedlingstothemeteringunit.Fullyautomaticvegetabletransplantersrequireeitherplugsorpotseedlings.Asinitialinvestmentonproductionofplugsishighandmechanismsemployedfortheremovalofseedlingsfromthetrayarecomplex,useofpotseedlingsseemstobeabetteroption(Kumar&Raheman,2008).Paperpotsmadewithnewspaperhavebeenusedforraisingseed-lings(Furuki,Yamanishi,Matsumoto,Honma,&Takada,2003；Kumar&Raheman,2010；Ueno,Matsumura,&Miyaji,2002,pp.19e32).Paststudiesrevealthatfullyautomaticvegetabletransplanterscapableoffeedingandmeteringindividualpaperpotseedlinghavenotyetbeendeveloped.Designofvegetabletransplantersdependsuponthetypeofseedlingsused.Itisnotpossibletoobtaintheready-to-plantpaperpotseedlingswithpotsofuniformdimensionsandfirmness.Inordertoovercomethedifficultyofhandlingpaperpotsofnon-uniformdimensionsandfirmness,pastresearchers(Nambu&Tanimura,1992；Suggsetal.,1987；Tsuga,2000；Yonetani,Matsumoto,&Okishio,1999)madestrandsorchainsofpaperpots.Thestrandofpotswasfedtoamechanisminthetransplanterthatcutthestrandatuniformintervalsanddroppedindividualpotsinsoil.Hence,thedesignofdevicesforseedlingpick-up,meteringandplantinginafullyauto-matictransplanterforindividualpaperpotseedlingsmustaccommodatethevariabilityindimensionsofthepots.Thegoalofthisworkwastodevelopawalk-behindtypehandtractor-poweredfullyautomaticvegetabletransplanterforpaperpotseedlingsandevaluateitsperformanceunderactualfieldconditions.3.ConceptualworkingofvegetabletransplanterforpaperpotseedlingsSeveraldeviceshavebeendevelopedforpickingup,meteringandplantingofplugs(Shaw,1999),potandbare-rootseedlings(Kumar&Raheman,2008).Manyofthesedevicescannotbeusedfortheremovalofpaperpotseedlingsfromatray.However,slightmodificationofthehorizontalconveyorwithflightstocarrytheseedlingsinuprightorientationbetweenFig.1eReady-to-plantpaperpotseedlingsoftomato.meteringconveyor.Asthemeteringconveyorcontinuouslydevice.Itwasdesignedforattachingto9.75kWVSTShakti130DIwalk-behindtypehandtractor(VSTTillerTractorsLtd.,Bengaluru,India).Therotavatortillageassemblyisanintegralpartofthehandtractorandhastoberemovedcompletelytoattachthevegetabletransplantertothehandtractor.Thefeedingconveyorwaspoweredfromthedriveshaftoftherotavatorofthehandtractor.Themeteringconveyorwaspoweredfromthegroundwheelshaftofthehandtractor.Thetractivepowerofthehandtractorwasutilisedbythefurrowopenerandsoilcoveringdevicestoovercomesoilresistance.Table1eFinaldimensionsandweightofpaperpotwithmix.ParticularsMeanC6std.dev.Maximumwidthandbreadth,mm45.0C63.0Widthandbreadthatthebottom,mm36.0C62.0Height,mm36.0C62.0Maximumdiagonallength,mm64.0C64.0Weightofpaperpotseedlingatpottingmixmoisturecontentof5C62%,10C62%and15C62%(drybasis),g65.0C62.0,68.0C62.0and74.0C62.0,respectively.biosystemsengineering110(2011)189e197191pushestheseedlingstowardsthefurrow,itisimportanttofeedthesinglepotseedlinginanuprightorientationbetweentheflightsatthespecifiedinterval.Inordertoachievethis,potseedlingshavetobearrangedintheformofarectangulararraywithseedlingsineachlinealignedtoenterthespacebetweentheflightsasandwhentheyreachthemeteringconveyor.Insteadofarrangingseedlingsintheformofarectangulararrayintrays,theycanbearrangedonaslattypehorizontalconveyorsuchthateachseedlingontheslatisfeddirectlybetweentheflightsofthemeteringconveyorattheappropriatetimeinterval.Thisconveyorisreferredtoasthefeedingconveyor.Anautomaticfeedingmechanism(AFM)wasprovidedtocoordinatetheworkingoffeedingandmeteringconveyorssothatalineararrayofpotseedlingsisfedtothemeteringconveyorattheappropriatetime.Theconceptualworkingofthearraytypevegetabletransplanter(AVT)isshowninFig.2.Itisafullyautomatictransplanterasseedlingsplacedonceonthefeedingconveyorarefedauto-maticallytothemeteringconveyorandthenplantedinthefurrowwithouthumanintervention.4.DevelopmentofAVTTheAVTconsistedoffeedingconveyor,meteringconveyor,AFM,seedlingdroptube,furrowopenerandsoilcovering1999)isabletoaccommodatesmallvariationsindimensionsofpaperpots.Hence,ahorizontalpushertypeconveyorwithflightstopushthepotseedlingwasselectedformeteringindividualpaperpotseedlingsanditisreferredtoastheMeteringconveyorFeedingconveyorGuidechannelPaperpotseedlinginSeedlingdischargepointabFig.2eConceptualworkingofvegetabletransplanterforpaperfeedingconveyor,(b)Feedingofonelineararrayofseedlingstocontinuouslytowardstheseedlingdischargepoint.Flightuprightorientationcpotseedlings(a)Arrangementofpaperpotseedlingson4.1.NumberofrowsandspacefortheattachmentofAVTinhandtractorAstractivepowerislowandinefficient,thenumberofrowsofseedlingstobeplantedbytheAVTwasdecidedbasedonmaximumutilisationofthetractivepowerofthehandtractor.Forwardspeedofthehandtractorduringtransplantingwasassumedtobeintherangeof0.9e1.5kmhC01basedontherangeofforwardspeedatwhichthe2WDtractorshavebeenoperatedwhenattachedtosemi-automatictransplantersinIndia(DARE,2006,pp.109e128；Manesetal.,2010).Theselectedrangeofforwardspeedofthehandtractorcouldbeobtainedwhenoperatedin1stlowgearat50e90%throttle.Theengineperformancecurvesindicatedthebrakehorse-poweroftheengineat50%throttle(1200rpm)as4.5kW.About20%ofengineoutputpowerisavailableatthewheelaxleofthehandtractorwhenitisfittedandoperatingitsrotavator(Bhole&Tiwari,1977).Assumingtractiveefficiencyas40%(Kathirvel,Manian,&Balasubramanian,2001),tractivepowerofthehandtractorwas0.36kW.Consideringtheaveragevalueofunitdraftas30.92NcmC02(Roul,Raheman,Pansare,&Manchavaram,2008),thedraftrequirementofashovel-typefurrowopener(5cmwidthofcut)whileoperatingat8cmdepthwas0.618kN.Thedraftrequiredforthesoilcoveringdeviceswasassumedtobe20%ofthedraftrequiredbythefurrowopener,basedonthefactthatthesoilcoveringdevicesoperateatshallowerdepthandonsoilalreadydisturbedbythefurrowopener.Drawbarpowerrequiredataforwardspeedof0.9kmhC01forasetoffurrowopenerandsoilcoveringdeviceswas0.185kW.Therefore,thenumberofsetsoffurrowopenerandsoilcoveringdevicesthatcouldbeoperatedwiththeavailablethemeteringconveyor,(c)Conveyingoftheseedlingstractivepower0.36O0.1851.94z2.Hence,itwasdecidedtodevelopa2-rowvegetabletransplanter.The2-rowAVTconsistedoftwosetsoffeedingconveyor,meteringconveyor,seedlingdroptube,furrowopenerandsoilcoveringdevice,andanAFM,depthadjustmentwheelandhitchingarrangement.3Dsolidmodellingofthe2-rowAVT(Fig.3)wasdoneinMechanicalDesktopR6PowerPack(Autodesk,Inc.,SanRafael,USA).Thesolidmodellinghelpedindeterminingthespaceavailableforvariouscomponentsandidentifyingthepossiblecollisionofmachineelementsduringmotion.MechanicaldesignofindividualcomponentsofAVTwascarriedoutconsideringthepoweravailability,dimensionsofthepaperpotandspaceavailabilityinthehandtractorafterthecompleteremovalofrotavatortillageassembly.Duringthedesignprocess,theoverallwidthofAVTwastakenas1.5m.Afterthecompleteremovaloftherotavatorassembly,aspace1.0mlongwasavailablebehindthetrans-missioncasingofthehandtractorfortheattachmentofAVT.Therefore,spaceavailablefortheaccommodationofAVTbehindthehandtractorwas1.0mC21.5m.4.2.Feedingandmeteringconveyorshorizontalpushertypechainconveyor.Thefeedingconveyoroperatesonlyforthetimerequiredtomoveonelineararrayofpotseedlingsontheslattowardsthemeteringconveyor.TheengagementanddisengagementofdrivepowertothefeedingconveyoratappropriatetimeswasdoneusinganAFM.Overalllengthandwidthofeachfeedingconveyorwas800and600mm,respectively.Itensuredaspaceof300mmwidthand800mmlengthbetweenthetwofeedingconveyorsforprovidinganAFM.Italsoensuredaspaceof200mmlengthovertheentirewidthofAVTforprovidingfurrowopenersandsoilcoveringdevices.Eachslatofthefeedingconveyorcarried6potseedlingsatacentretocentredistanceof76.2mm.Eachfeedingconveyorhad18slats.Thetwofeedingconve