Presentation On Protected cultivation and secondary agriculture

It is a presentation about protected cultivation and secondary agriculture, which includes green House, types construction, irrigation system and many more things.

1. PROTECTED CULTIVATION
Greenhouse
Agreenhouseisaframedorinflatedstructurecoveredwitha
transparentortranslucentmaterialinwhichcropscouldbe
grownundertheconditionsofatleastpartiallycontrolled
environmentandwhichislargeenoughtopermitapersonto
workwithinittocarryoutculturaloperations
Greenhouse effect
WhenshortwaveradiationfromtheSunentersthe
greenhousestructure,itrefractsthroughthesurfaceandgets
transformedintolongwaveradiations.Theselongwave
radiationsdonotescapethegreenhouseinentirety,thereby
trappingtheheatandthus,continuallyincreasethe
temperatureinside.Thisisknownasthegreenhouseeffect.

2. PROTECTED CULTIVATION
Scope of greenhouse in India
•Cultivationinproblematicagroclimate:InIndia
majorityofuncultivatedareaisunderproblematic
conditionssuchasbarren,uncultivablefallowlandsand
desserts.Evenafractionofthisareabroughtunder
greenhousecultivationcouldproducesubstantialreturns
forthelocalinhabitants.
•Greenhousesaroundbigcities:Thesubstantialdemand
persistsforfreshvegetablesandornamentalsaroundthe
yearinbigcities.Demandforoffseasonandhighvalue
cropsalsoexistsinbigcities.Thereforegreenhouse
cultivationcanbepromotedtomeettheurban
requirements.
•Exportofhorticulturalproduce:Thereisagood
internationaldemandforhorticulturalproduce,mainly
thecutflowers.Promotionofgreenhousecultivationof
exportorientedcropswillbeofdefinitehelptowards
exportpromotion.
•Greenhousesforplantpropagation:GHtechnologyis
beingnowadaysconsideredassuitableapproachfor
raisingofseedlingsandcuttingswhichrequirecontrol
environmentfortheirgrowth.GHfacilitycouldincrease
thecapacityandqualityofproducingtheplantmaterial.

3. PROTECTED CULTIVATION
Scope of greenhouse in India
•Greenhousetechnologyforbiotechnology:Material
generatedthroughtissuecultureareneedtobe
propagatedincontrolenvironment.Thehydroponicsor
NutrientFilmTechnique(NFT)arealsorequired
controlledenvironmentalconditionsforgrowingplants.
•Greenhouseforcultivationofrareandmedicinal
plants:Indiahaswidevarietyofmedicinalherbsand
rareplantslikeorchidswhichhavebeenidentifiedfor
largescalecultivation.Thegreenhousecouldprovidethe
righttypeofenvironmentalconditionsfortheintensive
cultivationoftheseplants.

4. PROTECTED CULTIVATION
Status of protected cultivation in World
•Greenhousecropproductionispracticedoveran
estimatedareaof4,05,000haspreadoverallthe
continents
•Morethan55countriescultivatescropsundercoveron
commercialscaleandiscontinuouslygrowingatafaster
rate.
•InIndia,protectedcultivationtechnologyforcommercial
productionishardlythreedecadesold.
•Incountriesviz.,Japan,Netherland,Russia,UK,
Chinaandothers,itisabouttwocenturyold.
•Chinastartedprotectedcultivationin1990’sandtoday
theareaunderprotectedcultivationinChinaismorethan
2.5mhaand90percentareaisundervegetables.
•Israelproducesqualityfruits,vegetables,flowers,etc.in
waterdeficitdesertarea
•SeveralthousandacresarenowunderglassintheUnited
StatesandequallylargeareainEnglandandNetherland,
wherehorticultureunderglasswaspracticedovera
centuryago.

5. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Lean to type greenhouse
•Halfgreenhouse,splitalongthepeakoftheroof,orridge
line.
•Usefulwherespaceislimitedtoawidthof7to12feet.
•Placedagainstthesideofanexistingbuilding.
•Leastexpensivestructure.
•Makesthebestuseofsunlightandminimizesthe
requirementofroofsupports.
•Theroofofthebuildingisextendedwithappropriate
greenhousecoveringmaterialandtheareaisproperly
enclosed.

6. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Lean to type greenhouse
•Disadvantagesincludelimitationsonspace,sunlight,
ventilation,andtemperaturecontrol.
•Theheightofthesupportingwalllimitsthepotentialsize
ofthelean-to.
•Thewidertheleanto,thehigherthesupportingwall
mustbe.
•Temperaturecontrolisdifficultbecausethewallthatthe
greenhouseisbuiltonmaycollectthesun’sheatwhile
thetranslucentcoverofthegreenhousemayloseheat
rapidly.
•Facethebestdirectionforadequatesunexposure.

7. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Even span type greenhouse
•Inthistype,thetworoofslopesareofequalpitchand
width.
•Thisdesignisusedforthegreenhouseofsmallsize,and
itisconstructedonleveledground.
•Severalsingleandmultiplespantypesareavailablefor
useinvariousregionsofIndia.
•Forsinglespantype,thespaningeneralvariesfrom5to
9m,whereasthelengthisaround24m.Theheight
variesfrom2.5to4.3m.

8. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Uneven span type greenhouse
•Thistypeofgreenhouseisconstructedonhillyterrain.
•Theroofsareofunequalwidth;makethestructure
adaptabletothesideslopesofhill.
•Thistypeofgreenhousesisseldomusednow-a-daysas
itisnotadaptableforautomation.

9. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
•DesignsofthistypeusetwoormoreA-frame
greenhousesconnectedtooneanotheralongthelengthof
theeave.
•Theeaveservesasfurroworguttertocarryrainand
meltedsnowaway.
•Thesidewalliseliminatedbetweenthegreenhouses,
whichresultsinastructurewithasinglelargeinterior,
Consolidationofinteriorspacereduceslabour,
lowersthecostofautomation,improvespersonal
managementandreducesfuelconsumptionasthereis
lessexposedwallareathroughwhichheatescapes.
Ridge and furrow Type Greenhouse

10. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
•Thesnowloadsmustbetakenintotheframe
specificationsofthesegreenhousessincethesnow
cannotslideofftheroofsasincaseofindividualfree
standinggreenhouses,butmeltsaway.
•Inspiteofsnowloads,ridgeandfurrowgreenhousesare
effectivelyusedinnortherncountriesofEuropeandin
CanadaandarewellsuitedtotheIndianconditions.
Ridge and furrow Type Greenhouse

11. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Saw Tooth Type Greenhouse
•Thesearealsosimilartotheridgeandfurrowtype
greenhousesexceptthat,thereisprovisionfornatural
ventilationInthistype.
•Specificnaturalventilationflowpathdevelopsinasaw
toothtypegreenhouse.

12. •Inquonsetgreenhouse,thepipearchesortrussesare
supportedbypipepurlinsrunningalongthelengthofthe
greenhouse.
•Ingeneral,thecoveringmaterialusedforthistypeof
greenhousesispolyethylene.
•Suchgreenhousesaretypicallylessexpensivethanthe
gutterconnectedgreenhousesandareusefulwhenasmall
isolatedculturalareaisrequired.
•Thesehousesareconnectedeitherinfreestandingstyleor
arrangedinaninterlockingridgeandfurrow.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on shape
Quonset Greenhouse

13. GreenhouseTypeBasedonUtility:
•Classificationofgreenhousescanalsobemadedepending
onthefunctionsorutilities.
•Ofthedifferentutilities,artificialcoolingandheatingof
thegreenhousearemoreexpensiveandelaborate.
•Hencebasedontheartificialcoolingandheating,
greenhousesareclassifiedasthatusesactiveheating
systemandactivecoolingsystem.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on utility
GreenhousesforActiveHeating:
•Duringthenighttime,theairtemperatureinside
greenhousedecreasesandtoavoidthecoldbitetoplants
duetofreezing,someamountofheathastobesupplied.
•Therequirementsforheatinggreenhousedependonthe
rateatwhichtheheatislosttotheoutsideenvironment.
•Variousmethodsareadoptedtoreducetheheatlosses,
namely,usingdoublelayerpolyethylene,thermopane
glasses(twolayersoffactorysealedglasswithdeadair
space)ortouseheatingsystems,suchasunitheaters,
centralheat,radiantheatandsolarheatingsystem.

14. GreenhousesforActiveCooling:
•Duringsummerseason,itisdesirabletoreducethe
temperaturesofgreenhousethantheambient
temperatures,foreffectivecropgrowth.
•Hencesuitablemodificationsaremadesothatlarge
volumesofcooledairaredrawnintogreenhouse.
•Thistypeofgreenhouseeitherconsistsofevaporative
coolingpadwithfanorfogcooling.
•Thisgreenhouseisdesignedinsuchawaythatitpermits
aroofopeningof40%andinsomecasesnearly100%.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on utility

15. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on construction
WoodenFramedStructures:
•Ingeneral,forgreenhouseswithspanlessthan6m,only
woodenframedstructuresareused.
•Sidepostsandcolumnsareconstructedofwoodwithout
theuseofatruss.
•Pinewoodiscommonlyusedasitisinexpensiveand
possessestherequiredstrength.
•Timberlocallyavailable,withgoodstrength,durability
andmachinabilityalsocanbeusedfortheconstruction.

16. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on construction
Pipe Framed Structures:
•When the clear span is around 12 m, pipes are used for the
construction of greenhouses.
•In general, the side posts, columns, cross-ties and purl ins
are constructed using pipes.
•Trusses are not used also in this type of greenhouse.
•The pipe components are not interconnected but depend
on the attachment to the sash bars for support.

17. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on construction
TrussFramedStructures:
•Ifthegreenhousespanisgreaterthanorequalto15m,truss
framesareused.
•Flatsteel,tubularsteelorangleironisweldedtogetherto
formatrussencompassingrafters,chordsandstruts.
•Strutsaresupportmembersundercompressionandchords
aresupportmembersundertension.
•Angleironpurlinsrunningthroughoutthelengthof
greenhouseareboltedtoeachtruss.
•Columnsareusedonlyinverywidetrussframehousesof
21.3mormore.
•Mostoftheglasshousesareoftrussframetype,asthese
framesarebestsuitedforpre-fabrication.

18. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
•Coveringmaterialsarethemajorandimportant
componentofthegreenhousestructure.
•Coveringmaterialshavedirectinfluenceonthe
greenhouseeffectinsidethestructureandtheyalterthe
airtemperatureinsidethehouse.
•Thetypesofframesandmethodoffixingalsovaries
withthecoveringmaterial.
•Basedonthetypeofcoveringmaterials,thegreenhouses
areclassifiedasglass,plasticfilmandrigidpanel
greenhouses.
Glass Greenhouse
•Till1950,onlyglassgreenhouseswithglassasthe
coveringmaterialexisted.
•Glassascoveringmaterialhastheadvantageofgreater
interiorlightintensity.
•Thesegreenhouseshavehigherairinfiltrationrate
whichleadstolowerinteriorhumidityandbetter
diseaseprevention.
•Lean-totype,evenspan,ridgeandfurrowtypeof
designsareusedforconstructionofglassgreenhouse.

19. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

20. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
Plastic film Greenhouse
•Flexibleplasticfilmsincludingpolyethylene,polyester
andpolyvinylchlorideareusedascoveringmaterialin
thistypeofgreenhouses.
•Plasticsascoveringmaterialforgreenhouseshave
becomepopular,astheyarecheapandthecostof
heatingislesswhencomparedtoglassgreenhouses.
•Themaindisadvantagewithplasticfilmsisitsshortlife.
•Forexample,thebestqualityultraviolet(UV)stabilized
filmcanlastforfouryearsonly.
•Quonsetdesignaswellasgutter-connecteddesignis
suitableforusingthiscoveringmaterial.

21. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
Rigid panel Greenhouse
•Polyvinylchloriderigidpanels,fibreglass-reinforced
plastic,acrylicandpolycarbonaterigidpanelsare
employedasthecoveringmaterialinthequonsettype
framesorridgeandfurrowtypeframe.
•Comparativelyresistanttobreakageandthelight
intensityisuniformthroughoutthegreenhousewhen
comparedtoglassorplastic.
•Highgradepanelshavelonglifeevenupto20years.

22. •Themaindisadvantageisthatthesepanelstendtocollect
dustaswellastoharboralgae,whichresultsin
darkeningofthepanelsandsubsequentreductioninthe
lighttransmission.
•Thereissignificantdangeroffirehazard.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
Rigid panel Greenhouse

23. PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
Cladding material: Transparent material mounted on the walls and roof of a green house.
Rigid cladding material: Cladding material with such a degree of rigidity that any deformation of the structure may result in
damage to it. Ex. Glass
Flexible cladding material: Cladding material with such a degree of flexibility that any deformation of the structure will not
result in damage to it. Ex. Plastic film
Properties of ideal greenhouse covering material:
1. It should transmit the visible light portion of the solar radiation, which is utilized by plants for photosynthesis
2. It should absorb the small amount of UV in the radiation and convert a portion of it into visible light useful for plants
3. It should reflect or absorb IR radiation which are not useful to plants and causes greenhouse interiors to overheat
4. It should be low cost
5. It should have usable life of 10 to 20 years
Covering material: They are of glass, fiberglass, or plastic. Each type has its advantages and disadvantages

24. a.Glass–90%lighttransmission
b.Fiberglass–90-95%lighttransmission
c.Polyethylene–65-75%lighttransmission
d.Vinyl–90%lighttransmission
a.Glass:
•Glasstypegreenhousesarethemosttraditionalcoveringused.
•Theymaybeconstructedwithslantedsides,straightsidesandeaves.
•Aluminum,glassbuildingsprovidelowmaintenanceandhaveaestheticlines,aswellasensuringthatyougeta
weather-tightstructure.
•Pre-fabricatedglasskitsareavailableforeasyinstallationbyamateurgardeners.
•Thedisadvantagesofglassareitsfragilecondition(glassbreakseasily)andhighcosts.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

25. b.Fiberglass:
•Fiberglassgreenhouses–theyarelight,strongand
hail-proof.
•Becareful,thoughlowqualityfiberglasswilldiscolor,
thusreducingpenetrationoflight.
•Usingagoodqualityfiberglasswillhowevermakeit
asexpensiveasbuildingaglassone.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

26. c.Plastic:
Plasticgreenhousesarebecomingverypopularforthe
followingreasons:
1.Lowcost(about1/6thecostofglass)
2.Absorbssufficientheat
3.Lowcost(about1/6thecostofglass)
4.Fruitsandvegetablesandotherplantsunderplasticare
comparableinqualitytothatofglass-grownvarieties
5.Choiceofpolyethylene(PE),polyvinylchloride(PVC),
copolymersofthesematerials,andotherreadilyavailable
clearfilms.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

27. 1.Polyethylene:
•Commonlyusedplasticforgreenhousecoveringis
thermoplastic.
•Thebasiccharacteristicistheysoftenonheatingandhardens
withcoolingandtheprocessisreversible.
•Theyarestiff,robust,resiliencetoresistloadsand
deformations.
•Polyethyleneusedforcoveringyearroundproductionhave
UVinhibitorinitotherwiselastsonlyoneheatingseason.
•Standardlengthsincludes30.5,33.5,45.7,61.0and67.0m.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

28. 1.Polyethylene:
•Apolyethylenecoveringiscolderthanairinsidegreenhouse
inwinterduetowhichwhenwarmairinsidecomeincontact
notimethewaterfallsasbeadsovertheplant.
•Thewetfoliagecausesdiseasesandalsotheconstantly
wettedsoilbecomeswaterloggedandoxygendeficient.
•Withthewaterdrippingproblem,condensationalsoreduces
lightintensitywithingreenhouseusageofanti-fogsurfactant
isrecommended.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

29. 2.Polyvinylchloridefilm:
•UVresistantvinylfilmsof0.2and0.3mmthicknessareguaranteedfor4-5
yearsrespectively.
•Thisextendedlifeofpolyvinylfilmisadvantageousascomparedto
polyethylenewhichhasonly1or2years.
•Buttheadventof4yearpolyethylenetheadvantageofvinylfilmhasgone.
•Thecostof0.3mmvinylis3timesthatof0.15mmpolyethylene.
•Thevinylfilmstendtoholdastaticelectricchargeduetowhichitattracts
andholdsthedustthatreducesthelighttransmittanceunlessthedustis
washedaway.
•InJapan95%greenhousesareunderplasticandwithinthegroup90%are
coveredofvinylfilm.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

30. 3.Polyesterfilm:
•Polyestersofferslonglifeandarestrong.
•Filmsof0.13mmthicknessareusedforroofswilllastfor4
years,while0.08mmfilmsareusedonverticalwallhave
lifeexpectancyofsevenyears.
•Althoughpolyesterhavingthehighercostascomparedto
polyethyleneitofferstheextralifeexpectancy.
•Theadvantageincludelighttransmittanceequaltothatfor
glassPolyesterisstillfrequentlyusedinheatretention
screensbecauseitshighcapacitytoblockradiantenergy.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

31. 4.TefzelT
2
film(Ethylenetetrafluoroethylene):
•Itistherecentadditionofplasticcovering.
•Thisfilmwasearlierusedfortransparentcoveringonsolar
collector.
•Thelifeexpectancyis20yearsormore.
•Thelighttransmissionis95%andisgreaterthanthatofany
othercoveringmaterial.
•Doublelayerwillhaveabout90%transmittance.
•ItismoretransparenttoIRradiationsothatlessheatistrapped
insideduetowhichthecostofcoolingwillbereduced.
•DisadvantageofTefzelfilmisavailabilityonlyin1.27mwide
rollswhichrequiresclampingrailsonevery1.2m.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

32. 5. Fiberglass reinforced plastic rigid panel:
•Mostpopularmaterialinpast.
•Lifeperiodvarieswithgrade.
•Somegradesgive5-10yearswhilebettergradescanlastupto20
years.
•Corrugatedpanelsareusedbecauseofgreaterstrength.
•Flatpanelsareusedforsidewallswhereloadisnotgreater.
Availablewidth1.3mandlengthupto7.3m.
•PanelsareflexibleenoughtoconformtoshapeofQuonset
greenhouse.
•ResistanttobreakagebyhailsorVandels.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material

33. 6.Acrylicandpolycarbonaterigidpanel:
•Acrylicandpolycarbonatefilmshavebeenavailableforuse
since15years.
•Thepanelsusedforglazingthesidewallsandendwallsof
filmplasticgreenhousesandforretrofittingoldgreenhouses.
•Acrylicgreenhousesarehighlyinflammable.
•Acrylicpanelsarepopularduetohighlighttransmissionand
longerlife.
•Polycarbonatepanelsareforcommercialgreenhousesdueto
lowprice,flameresistanceandrésistancetohaildamage.
•Availablewithcoatingtopreventcondensationandalsoan
acryliccoatingforprotectionfromUVlight.
PROTECTED CULTIVATION
Different types of protected structures
Greenhouse type based on covering material
Acrylic Polycarbonate

34. •Thecropproductivitynotonlydependsonitshereditybut
alsobythemicro-climatearoundit.
•Thecomponentsofcropmicro-climatearelight,
temperature,aircompositionsandthenatureofthe
rootmedium.
•Inopenfields,onlymanipulationofthenatureoftheroot
mediumbytillage,irrigationandfertilizerapplicationsis
possible.
•Ingreenhousecasealso,thenatureoftherootmediumis
modifiedbutnotcontrolled.
•Greenhousepermitscontrolofanyoneormoreofthe
componentsofthemicro-climate.
PROTECTED CULTIVATION
Plant response to greenhouse environment

35. PROTECTED CULTIVATION
Plant response to greenhouse environment
•Thevisiblelightofthesolarradiationisasourceofenergyforplants.
•Lightenergy,carbondioxide(CO
2)andwaterareutilizedintotheprocessofphotosynthesisandcarbohydratesareformed.
•Theproductionofcarbohydratesfromcarbondioxideandwaterinthepresenceofchlorophyll,usinglightenergyis
responsibleforplantgrowthandreproduction.
•Therateofphotosynthesisisgovernedbyavailablefertilizerelements,water,carbondioxide,lightandtemperature.
•Ifthelightintensityisdiminished,photosynthesisslowsdownandhencethegrowth.Ifhigherthanoptimallightintensities
areprovided,growthagainslowsdownbecauseoftheinjurytothechloroplasts.
The photosynthesis reaction can be represented as follows:
Light

36. PROTECTED CULTIVATION
Plant response to greenhouse environment
•Thelightintensityismeasuredbytheinternationalunitknownaslux.
•Greenhousecropsaresubjectedtolightintensitiesvaryingfrom129.6kluxonclear
summerdaysto3.2kluxoncloudywinterdays.Formostcrops,neitherconditionis
ideal.
•Manycropsbecomelight-saturated,inotherwords,photosynthesisdoesnotincreaseat
lightintensitieshigherthan32.3klux.
•Lightisclassifiedaccordingtoitswavelengthinnanometers(nm).
•Notalllightisusefulinthephotosynthesisprocess.UVlightisavailableintheshort
wavelengthrange,i.e.lessthan400nm.Largequantitiesofitarealsoharmfultothe
plants.
•GlassscreensareopaquetomostUVlightandlightbelowtherangeof325nm.
•Visibleandwhitelighthaswavelengthsof400to700nm
Light

37. •Itisprimarilythevisiblespectrumoflightthatisusedinphotosynthesis.
•Infrared(IR)raysoflongerwavelengthsarenotinvolvedintheplantprocess.
•Intheredbandsthephotosyntheticactivityishigher.
•Whenthebluelight(shorterwavelengths)aloneissuppliedtoplants,thegrowthis
retarded,andtheplantbecomeshardanddarkincolour.
•Whenplantsaregrownunderredlight(longerwavelengths),growthissoftand
internodesarelong,resultingintallplants.
•Visiblelightofallwavelengthsisreadilyutilizedinphotosynthesis.
PROTECTED CULTIVATION
Plant response to greenhouse environment
Light

38. PROTECTED CULTIVATION
Plant response to greenhouse environment
Temperature
•Temperatureisameasureofthelevelofheatpresent.
•Differentcropshavedifferenttemperaturerangeinwhichtheycangrowwell.
•Belowthisrange,theplantlifeprocessesstopduetoiceformationwithinthetissuetyingupwater,and
cellsarepossiblypuncturedbyicecrystals.
•Attheupperextreme,enzymesbecomeinactive,andagaintheenzymecontrolledprocessesessentialfor
lifecease.Enzymesarebiologicalreactioncatalystandareheatsensitive.

39. •Therateofreactionscontrolledbytheenzymeoftendoublesortriplesforeachriseoftemperatureby
10°C,untilanoptimumtemperatureisreached.Furtherincreaseintemperaturebeginstosuppressthe
reactionandfinallystopsit.
•Asageneralrule,greenhousecropsaregrownat·adaytemperature,whichis3°Cto6°Chigherthanthe
nighttemperatureoncloudydaysand8°Chigheroncleardays.
•WithCO2enrichment,thedaytemperaturesmaybehigherby3°C.
•Thenighttemperatureofgreenhousecropsisgenerallyintherangeof7°Cto21°C.
•Primula,mathiolaincanaandcalceolariagrowbestat7°C,carnationandcinerariaat10°C,roseat16°C,
chrysanthemumandpoinsettiaat17°Cto18°Candafricanvioletat21°Cto22°C.
PROTECTED CULTIVATION
Plant response to greenhouse environment
Temperature

40. PROTECTED CULTIVATION
Plant response to greenhouse environment
Relative humidity
•Asthegreenhouseisanenclosedspace,therelativehumidityofthegreenhouseairwillbemorewhencomparedto
theambientair,duetothemoistureaddedbytheevapotranspirationprocess.
•Someofthismoistureistakenawaybytheairleavingfromthegreenhouseduetoventilation.
•Sensibleheatinputsalsolowertherelativehumidityoftheairtosomeextent.
•Inordertomaintaindesirablerelativehumiditylevelsingreenhouses,processeslikehumidificationor
dehumidificationarecarriedout.
•Formostcrops,theacceptablerangeofrelativehumidityisbetween50to80%.
•However,forplantpropagationwork,relativehumidityupto90%maybedesirable.

41. •Insummersduetosensibleheatadditioninthedaytime,andinwintersforincreasingthenighttimetemperature
ofthegreenhouseair,moresensibleheatisaddedthatcausesareductionintherelativehumidityoftheair.
•Forthepurposeofmaintainingrelativehumiditylevels,evaporativecoolingpadsandfoggingsystemsof
humidificationareemployed.
•Whentherelativehumidityisonthehigherside,ventilators,chemicaldehumidifiersandcoolingcoilsareusedfor
dehumidification.
PROTECTED CULTIVATION
Plant response to greenhouse environment
Relative humidity

42. PROTECTED CULTIVATION
Plant response to greenhouse environment
Ventilation
•Agreenhouseisventilatedforeitherreducingthetemperatureofgreenhouseair,orforreplenishing
carbondioxidesupply,orformoderatingtherelativehumidityoftheair.
•Airtemperaturesabove35°Caregenerallynotsuitedtocropsingreenhouse.
•Itisquitepossibletobringgreenhouseairtemperaturebelowthisupperlimitduringspringandautumn
seasonsbysimplyprovidingadequateventilationforthegreenhouse.
•Theventilationinagreenhousecaneitherbenaturalorforced.Incaseofsmallgreenhouses(lessthan6
mwide)naturalventilationcanbequiteeffectiveduringspringandautumnseasons.
•However,forcedventilationusingfansisessentialforprecisecontrolovertheairtemperature,humidity
andcarbondioxidelevels.

43. •Carbonisanessentialplantnutrientwhichispresentingreaterquantitythananyothernutrientinthe
plant.
•About40%ofthedrymatterofplantsiscomposedofcarbon,andcarbondioxide(CO
2)gasintheairis
theimportantsourceofcarbontoplants.
•Undernormalconditions,CO
2exitsasagasintheatmosphereslightlyabove0.03%or345ppm.
•Duringtheday,whenphotosynthesisoccursundernaturallight,theplantsinagreenhousedrawdown
thelevelofCO
2tobelow200ppm.
PROTECTED CULTIVATION
Plant response to greenhouse environment
Carbon dioxide

44. •Underthesecircumstances,infiltrationorventilationincreasesCO
2levels,wheretheoutsideairis
broughtintomaintaintheCO
2atambientlevels.IfthelevelofCO
2islessthanambientlevels,CO
2
willbecomethefactorofretardingtheplantgrowth.
•Incoldclimates,maintainingambientlevelsofCO
2byprovidingventilationmaybeuneconomical,
duetothenecessityofheatingtheincomingairinordertomaintainpropergrowingtemperatures.In
suchregions,enrichmentofthegreenhousewithCO
2isfollowed.
•TheexactCO
2levelneededforagivencropwillvary,sinceitmustbecorrelatedwithother
variablesingreenhouseproductionsuchaslight,temperature,nutrientlevels,cultivaranddegreeof
maturity.MostcropswillrespondfavourablytoCO
2at1000to1200ppm.
PROTECTED CULTIVATION
Plant response to greenhouse environment
Carbon dioxide

45. PROTECTED CULTIVATION
Planning and Design of green house:
•Agreenhouse,isbasicallythepurposeofprovidingandmaintainingagrowingenvironmentthatwillresult
inoptimumproductionatmaximumyield.
•Theagricultureinthecontrolledenvironmentispossibleinalltheregionsirrespectiveofclimateand
weather.
•Itisanenclosingstructureforgrowingplants,greenhousemustadmitthevisiblelightportionofsolar
radiationfortheplantphotosynthesisand,therefor,mustbetransparent.
•Atthesametime,toprotecttheplants,agreenhousemustbeventilatedorcooledduringthedaybecauseof
theheatloadfromtheradiation.
•Thestructuremustalsobeheatedorinsulatedduringcoldnights.
•Agreenhouseactsasabarrierbetweentheplantproductionareasandtheexternalorthegeneral
environment.

46. Site selection and orientation
PROTECTED CULTIVATION
•Agreenhouseisdesignedtowithstandlocalwind,snowandcroploadsforaspecificcroppingactivity.
•Inthisway,thestructurebecomeslocationandcropspecific.
•Thebuildingsiteshouldbeaslevelaspossibletoreducethecostofgrading,andthesiteshouldbe
wellaeratedandshouldreceivegoodsolarradiation.
•Provisionofadrainagesystemisalwayspossible.
•Itisalsoadvisabletoselectasitewithanaturalwindbreak.
•Inregionswheresnowisexpected,treesshouldbe30.5mawayinordertokeepdriftsbackfromthe
greenhouses.
•Topreventshadowsonthecrop,treeslocatedontheeast,south,orwestsidesshouldbeatadistanceof
2.5timestheirheight.

47. Structural design
PROTECTED CULTIVATION
•Themostimportantfunctionofthegreenhousestructureanditscoveringistheprotectionofthecropagainst
hostileweatherconditions(lowandhightemperatures,snow,hail,rainandwind),diseasesandpests.
•Itisimportanttodevelopgreenhouseswithamaximumintensityofnaturallightinside.
•Thestructuralpartsthatcancastshadowsinthegreenhouseshouldbeminimized.
•Thedifferentstructuraldesignsofgreenhousebasedonthetypesofframesareavailable.
•Astraightsidewallandanarchedroofispossiblythemostcommonshapeforagreenhouse,butthegableroofis
alsowidelyused.
•Bothstructurescanbefreestandingorgutterconnectedwiththearchroofgreenhouse.
•Thearchroofandhoopstylegreenhousesaremostoftenconstructedofgalvanizedironpipe.Iftallgrowing
cropsaretobegrowninagreenhouseorwhenbenchesareused,itisbesttouseastraightsidewallstructure
ratherthanahoopstylehouse,thisensuresthebestoperationaluseofthegreenhouse.

48. PROTECTED CULTIVATION
Structural design
•Ahooptypegreenhouseissuitableforlowgrowingcrops,suchaslettuce,ornurserystockwhicharehoused
throughoutthewinteringreenhouseslocatedinextremelycoldregions.
•Agothicarchframestructurecanbedesignedtoprovideadequatesidewallheightwithoutlossofstrengthtothe
structure.
•Loadsindesigningthegreenhousestructuresincludetheweightofthestructureitselfand,ifsupportedbythe
structure,loadsoftheequipmentfortheheatingandventilationandwaterlines.
•Greenhousestructuresshouldbedesignedtoresista130km/hwindvelocity.
•Theactualloaddependsonwindangle,greenhouseshapeandsize,andthepresenceorabsenceofopeningsandwind
breaks.

49. PROTECTED CULTIVATION
Greenhouse Design
A straight side wall and an arched roof
•Common shape for a greenhouse
•Structure can be free standing or gutter connected with the
arch roof greenhouse
•Commonshapeforagreenhouse
•Structurecanbefreestandingorgutterconnectedwiththe
archroofgreenhouse
A straight side wall and a gothic or
gable roof

50. PROTECTED CULTIVATION
Greenhouse Design
A Gothic arch frame structure
•AGothicarchframestructurecanbedesignedtoprovideadequateside
wallheightwithoutlossofstrengthtothestructure.
•Thisformofstructure,alongwithothers,canbeusedasasinglefree
standinggreenhouseorasalargerangeofmulti-span,gutterconnected
units.
The arch roof and hoop style
•Constructedofgalvanizedironpipebentintoformbyarollerpipebender
•Iftallgrowingcropsaretobegrowninagreenhouseorwhenbenchesare
used,itisbesttouseastraightsidewallstructure
•Ahooptypegreenhouseissuitableforlowgrowingcrops,suchaslettuce,
orfornurserystockthatarehousedthroughoutthewinteringreenhouses
locatedinextremelycoldregions.

51. Theultimatedesignofagreenhousedependsonthefollowingaspects:
Theoverallstructuraldesignandthepropertiesoftheindividualstructuralcomponents.
Thespecificmechanicalandphysicalpropertieswhichdeterminethestructuralbehaviourofthecoveringmaterials.
Thespecificsensitivityofthecroptolightandtemperaturetobegrowninthegreenhouse.
Thespecificrequirementsrelevanttothephysicalpropertiesofthecoveringmaterial.
Theagronomicrequirementsofthecrop.
PROTECTED CULTIVATION
Greenhouse Design

52. PROTECTED CULTIVATION
Greenhouse Design
•Thefollowingfactorsaretobeconsideredwhileselectinggreenhousecoveringmaterial:
•i.e.Light,Temperature,Weight,Resistanttoimpact,anddurabilitytooutdoorweatheringandthermalstabilityover
widerangeoftemperatures.
•Beforeselectingthecoveringmaterial,twoimportantpointsshouldbetakenintoconsideration:
•Thepurposeforwhichgreenhousefacilityisintendedandservicelifeofmaterial.
•Intemperatureregionswherehightemperaturesarerequired,thecoveringmaterialwithhighlighttransmissionandfar
IRabsorptionmustbeselected.
•Alsothelossofheatbyconductionshouldbeminimum.
Covering Materials

53. Theidealgreenhouseselectivecoveringmaterialshouldhavethefollowingproperties:
Itshouldtransmitthevisiblelightportionofthesolarradiationwhichisutilizedbyplantsforphotosynthesis.
ItshouldabsorbthesmallamountofUVintheradiationandconvertaportionofittofluoresceintovisiblelight,
usefulforplants.
ItshouldreflectorabsorbIRradiationwhicharenotusefultoplantsandwhichcausesgreenhouseinteriorsto
overheat.
Shouldbeofminimumcost.
Shouldhaveusablelifeof10to20years
PROTECTED CULTIVATION
Greenhouse Design