CONTROLLED RELEASE FERTILIZERSFOR SUSTAINABLE AGRICULTURE
Editedby
F.B.LEWU
DepartmentofAgriculture,CapePeninsulaUniversityof TechnologyWellingtonCampus,Wellington,SouthAfrica
TATIANAVOLOVA
DepartmentofBiotechnology,SiberianFederal University,Krasnoyarsk,Russia
SABUTHOMAS
SchoolofEnergyMaterials;SchoolofChemicalSciences, InternationalandInter-UniversityCentreforNanoscience andNanotechnology,MahatmaGandhiUniversity, Kottayam,Kerala,India
RAKHIMOLK.R.
InternationalandInter-UniversityCentreforNanoscience andNanotechnology,MahatmaGandhiUniversity, Kottayam,Kerala,India
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Contributors
AshithaA.
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
SoumiaAboulhrouz
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco
AimanE.Al-Rawajfeh DepartmentofChemicalEngineering,TafilaTechnicalUniversity,Tafila,Jordan
MohammadR.Alrbaihat MinistryofEducation,Ajman,UnitedArabEmirates
EhabM.AlShamaileh DepartmentofChemistry,TheUniversityofJordan,Amman,Ajman,Jordan
OthmaneAmadine
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco
SubinBalachandran
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
VinayaChandran
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
KarimDanoun
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco
YounessEssamlali
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco
IkramGanetri
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco
JesiyaSusanGeorge
InternationalandInterUniversityCentreforNanoscienceandNanotechnology,Mahatma GandhiUniversity,Kottayam,Kerala,India
AbdulGhaffar DepartmentofPhysics,UniversityofAgriculture,Faisalabad,Punjab,Pakistan
RakhimolK.R.
InternationalandInterUniversityCentreforNanoscienceandNanotechnology,Mahatma GandhiUniversity,Kottayam,Kerala,India
JayachandranK.
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
NandakumarKalarikkal
InternationalandInterUniversityCentreforNanoscienceandNanotechnology,Mahatma GandhiUniversity,Kottayam,Kerala,India
JyothisMathew
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
LinuMathew
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
StalinNadarajan
InstituteofPlantScience,AROVolcaniCenter,RishonLezion,Israel
MuhammadYasinNaz DepartmentofPhysics,UniversityofAgriculture,Faisalabad,Punjab,Pakistan
ChandraWahyuPurnomo
ChemicalEngineeringDepartment,UniversitasGadjahMada,Sleman,Yogyakarta, Indonesia
MayaRajan
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
HensSaputra AgencyfortheAssessmentandApplicationofTechnology,Jakarta,Indonesia
S.Shahena
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
HithaShaji
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
ShaziaShukrullah DepartmentofPhysics,UniversityofAgriculture,Faisalabad,Punjab,Pakistan
ReshmaSoman
SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
SuryaSukumaran
SchoolofPureandAppliedPhysics,MahatmaGandhiUniversity,Kottayam,Kerala,India
SabuThomas
InternationalandInterUniversityCentreforNanoscienceandNanotechnology,Mahatma GandhiUniversity,Kottayam,Kerala,India
RemyaV.R.
InternationalandInterUniversityCentreforNanoscienceandNanotechnology,Mahatma GandhiUniversity,Kottayam,Kerala,India
MohamedZahouily
VARENACenter,MAScIRFoundation,RabatDesign,Rabat,Morocco;Laboratoirede Matériaux,CatalyseetValorisationdesRessourcesNaturelles,UniversitéHassanIICasablanca,Morocco
Conventionalmethodsof fertilizerrelease
S.Shahena,MayaRajan,VinayaChandran,LinuMathew SchoolofBiosciences,MahatmaGandhiUniversity,Kottayam,Kerala,India
1.Introduction
Thefertilizerisanykindofmaterialthatisappliedtosoilortoplanttissues tosupplyoneormoreplantnutrientsessentialtothegrowthofplants.It maybenaturalorsyntheticallyproduced[1].
Managementofsoilfertilityhasbeenagreatproblemforthefarmersfor thousandsofyears.RecordsshowedthatEgyptians,Romans,Babylonians, andearlyGermanswereusingmineralsandmanuretoenhancethe productivityoftheirfarms.Themodernscienceofplantnutritionstartedin the19thcenturywiththeworkofGermanchemistJustusvonLiebig[1].
TheHaberprocessandtheOstwaldprocessdevelopedinthe1910and 1920smadeagreatrevolutioninthefertilizermanufacturingIndustry. Ammonia(NH3)isproducedfrommethane(CH4)gasandmolecular nitrogen(N2)throughtheHaberprocess,whichisthenconvertedinto nitricacid(HNO3)intheOstwaldprocess[2].
Thenitrogen-basedfertilizerproductionwasstartedwithBirkeland Eydeprocess,whichwasoneofthemostcompetingindustrialprocessesin thenitrogen-basedfertilizerproduction.Inthisprocess,theatmospheric nitrogen(N2)is fixedintonitricacid(HNO3)throughnitrogen fixation. Thenitricacidwasthenusedasasourceofnitrate(NO3 )[3].
Nowadays,ithasbeenestimatedthatalmosthalfthepeopleonthe Eartharecurrentlyfedasaresultofsyntheticnitrogenfertilizer.The developmentofsyntheticfertilizerhassignificantlysupportedglobal populationgrowth[4].Inthelast50years,theuseofcommercialfertilizers hasbeenincreasingsteadily;reachingalmost100milliontonsofnitrogen peryear,anditisestimatedthataboutone-thirdofthefoodproducednow couldnotbeproducedwithouttheadditionoffertilizers[5].Theuseof phosphatefertilizershasalsoincreasedfromninemilliontonsperyearin 1960to40milliontonsperyearin2000.YaraInternationalistheworld’ s largestproducerofnitrogen-basedfertilizers[6,7].
ControlledReleaseFertilizersforSustainableAgriculture
ISBN978-0-12-819555-0
https://doi.org/10.1016/B978-0-12-819555-0.00001-7
Thesupplyofnutrientsmustbeoptimumforthemaximumyieldofany crop.Thenutrientdeficiencywillresultinstuntingofplantsandthatwill graduallyreducetheyieldbyslowingdowntheprogressofthegrowth cycle,causinglatefruitinganddelayedmaturity.Theabilityofthecropto absorbthenutrientsfromthesoildependsuponthebiologicalactivity. Normallythenutrientdeficiencytakesplaceduringthegrowingseasonand dependsonthetemperatureandmoisturecontentofthesoil[8].Fertilizers enhanceplantgrowthtraditionally;eitheras,beingadditivesthatprovide nutrientsorbyenhancingtheeffectivenessofthesoilbymodifyingits waterretentionandaeration[9].Also,animportantcomponentofthe weedmanagementprogramistheefficientandappropriatemanagementof fertilizerintermsofevaluationofbestsourceofnutrients,optimumratesof fertilization,propertiming,andsuitablefertilizerplacement[3,10].
Theessentialprerequisiteforoptimizingnutrientapplicationisthe detailedknowledgeabouttheadditionofnutrients,ie.,theabsorptionof nutrientsbytheplants.Theappliednutrientsshouldsatisfytheplant requirementsandthemethodusedfortheapplicationshouldminimizethe leachingtotheenvironmentandtherebycontroltherateofenvironmental pollution[11].Thetypeoffertilizer,timingoffertilizerapplication,and seasonaltrendsarethemajorfactorsthataffecttheefficiencyoftheapplied N(nitrogen)tosatisfytheNdemandofthecrops[12,13].Theefficiencyof thecropstoabsorbtheNisinfluencedbythesoiltype,cropsequence,and theresidualandmineralizedN[14].Thereductionofnitrogenlossand increaseintheNuseefficiencycanbeimprovedbynumerousstrategies. Forexample,theuseofNsources,consumptionofslow-releasefertilizer, properplacementtechniques,andalsobytheuseofNinhibitors[15 17].
TheplantmetabolismiscoupledwiththeavailabilityoftheNsources becauseithasafundamentalroleinthe plantmetabolism.Itisnecessaryto optimizethemanagementofNresourcestothecroppingsystemtoincrease itsNuseefficiencyandtherebyimprovetheproductivity[18].Normally,this canbeachievedeitherbyincreasingtheproductionofNinthesoilorby increasingtheaccumulationofNcompoundsintheediblepartofthecrop[15].
Thenutrientsrequiredforhealthyplantlifeareclassifiedonthebasisof theelements;buttheseelementsarenotuseddirectlyasfertilizers.The compoundscontainingtheseelementsarethebasisoffertilizers.The macronutrientsareconsumedinlargerquantitiesbytheplants.Theyare presentinplanttissueinquantitiesfrom0.15%to6.0%onadrymatter (DM)(0%moisture)basis.Plantsaremadeupoffourmainelementssuchas hydrogen,oxygen,carbon,andnitrogen.Hydrogen,oxygen,andcarbon
willbeavailableintheformofwaterandcarbondioxide.Thenitrogenis foundintheatmosphereasatmosphericnitrogenwhichisunavailableto plants.Sothenitrogenisconsideredasthemostimportantfertilizersince nitrogenispresentinproteins,DNA,andothercomponentssuchas chlorophyll.Somebacteriaandtheirhostleguminousplantscan fix atmosphericnitrogen(N2)byconvertingittoammonia.Phosphateis requiredfortheproductionofDNAandATP,themainenergycarrierin cells,aswellascertainlipids.
Thefertilizercontains:
• Threemainmacronutrients:
◦ Nitrogen(N):leafgrowth
◦ Phosphorus(P):Developmentofroots, flowers,seeds,fruit
◦ Potassium(K):Strongstemgrowth,movementofwaterinplants, promotionof floweringandfruiting
• Threesecondarymacronutrients:calcium(Ca),magnesium(Mg),and sulfur(S)
• Micronutrients:copper(Cu),iron(Fe),manganese(Mn),molybdenum (Mo),zinc(Zn),boron(B).Ofoccasionalsignificancearesilicon(Si), cobalt(Co),andvanadium(V).
Micronutrientsarerequiredinsmallerquantities,inparts-per-million (ppm)andarepresentattheactivesitesofenzymesintheplanttissuesthat carryouttheplant’smetabolism[19].
2.Classification
Fertilizersareclassifiedinseveralways.
2.1Basedonthenutrientsupply
Onthebasisofthenutrientsupply,thefertilizerscanbeclassifiedinto straightfertilizersandcomplexfertilizers.
2.1.1Singlenutrientorstraightfertilizers
Asthenameindicates,thesinglenutrientorstraightnutrientfertilizersprovide asinglenutrienttotheplants(e.g.,K,P,orN).Ammoniaoritssolutionsarethe widelyusednitrogen-basedstraightfertilizers.Ammoniumnitrate(NH4NO3) andureaarepopularsourcesofnitrogen.Ureaishavingtheadvantagethatitis solidandnonexplosive,unlikeammoniaandammoniumnitrate.
Thesuperphosphatesarethemainstraightphosphatefertilizers.Single superphosphate(SSP)consistsof14% 18%P2O5,againintheformsof
Ca(H2PO4)2 andalsophosphogypsum(CaSO4$2H2O).Themainconstituentsoftriplesuperphosphate(TSP)are44% 48%ofP2O5 andnogypsum. Amixtureofsinglesuperphosphateandtriplesuperphosphateiscalleddouble superphosphate.Mostofthe(morethan90%)typicalsuperphosphatefertilizer iswater-soluble[20].
MuriateofPotash(MOP)isthemainpotassium-basedstraightfertilizer. MuriateofPotashconsistsof95% 99%KCl,andistypicallyavailableas 0-0-60or0-0-62fertilizer[21].
2.1.2Multinutrientorcomplexfertilizers
Themultinutrientorcomplexfertilizersprovidetwoormorenutrients (e.g.,NandP).Thecommonlyusedfertilizersarethecomplexfertilizers. Sincetheyconsistoftwoormorenutrientcomponents,theyareagain classifiedintobinaryfertilizersandthree-componentfertilizersorNPK fertilizers[20].
2.1.2.1Binary(NP,NK,andPK)fertilizers
Sincetheyprovidebothnitrogenandphosphorustotheplantstheyare calledNPfertilizers,e.g.,monoammoniumphosphate(MAP)anddiammoniumphosphate(DAP).TheactiveingredientinMAPisNH4H2PO4 andtheactiveingredientinDAPis(NH4)2HPO4.About85%ofMAPand DAPfertilizersaresolubleinwater.
2.1.2.2NPKfertilizers
Nitrogen,phosphorus,andpotassiumcontainingfertilizersarecalledthreecomponentfertilizersorNPKfertilizers.
2.2Basedonthepresenceorabsenceofcarbon
2.2.1Organicfertilizer
Organicfertilizersarerecycledplant-oranimal-derivedmatter.
2.2.2Inorganicfertilizer
Inorganicfertilizersorsyntheticfertilizersaresynthesizedbyvarious chemicaltreatments[20].
3.Modeofapplication
Theapplicationratesoffertilizerdependonthesoilfertility.Thefertilityof asoilisusuallyasmeasuredbyasoiltestaccordingtotheparticularcrop. Themethodofapplyingfertilizersdependsonthenatureofcropplants, theirnutrientneeds,andthesoil(Table1.1).
Table1.1 Acomparisonofdifferentmethodsoffertilizerapplication.
Typeof fertilizer
Solid fertilizers
Modeof applicationAdvantagesDisadvantages
A. Broadcasting
a. Basal application
b. Topdressing
B. Placement
a. Ploughsole placement
b. Deep placement
c. Localized placement
• Drilling
• Side dressing
1. Uniformdistribution.
2. Completelymixwithsoil.
3. Supplyingnitrogeninreadilyavailable formtogrowingplants.
1. Theplantsinthe fi eldcannotfully utilizethefertilizers.
2. Duetothepresenceoffertilizerall overthe field,theweedsalsoabsorb thenutrientsandtheweedgrowthis alsostimulatedbythefertilizer.
3. Largeamountofthefertilizerisneeded andnutrientsare fixedinthesoil.
1. Suitablefordrylandareasandpaddy fields.
2. Usedfortheplacementofammoniacal nitrogenousfertilizersparticularlyinthe rootzonesoil.
3. Preventsthelossofnutrientsbyrunoff.
4. Onlyadequateamountoffertilizeris appliedtothesoilclosetotheseedorto therootsofgrowingplants.
5. Suitablefortheapplicationofphosphatic andpotassicfertilizersinthecaseof cerealcrops.
6. Thereisminimumcontactbetweenthe soilandthefertilizer.
1. Duetothehigherconcentrationofthe solublesalts,thegerminatedseedsand youngplantsmaygetdamaged.
Table1.1 Acomparisonofdifferentmethodsoffertilizerapplication. cont’d
Typeof fertilizer
Modeof applicationAdvantagesDisadvantages
7. Thenutrientsareavailableonlyforthe cropplantsandtheweedsalloverthe fieldcannotmakeuseofthefertilizers.
8. Higherresidualresponseoffertilizers.
Liquid fertilizers
C. Bandplacement
a. Hill placement
b. Row placement
D. Pellet application
A. Startersolutions
1. Applicationoffertilizersinorchards.
2. Nutrientseasilyavailabletothecrop plants.
3. Laborsaving.
1. Usedfortheplacementofnitrogenous fertilizersinthepaddy fields.
1. Theapplicationofsolutiontoyoung vegetableplantletsparticularlyatthetime oftransplantation.
2. Helpsinrapidestablishmentandquick growthoftheseedlings.
1. Theseasonalchangethemodeof applicationoffertilizer.
B. Foliar application
1. Theleavescaneasilyanddirectlyabsorb thenutrientsthroughtheirstomatal openingsandalsothroughtheepidermis.
2. Aneffectivemethodoffertilization.
3. Leavescaneasilyabsorbseveralnutrient elements.
4. Theconcentrationofthefertilizer solutioncanbecontrolledmanually.
1. Signifi cantreductionoffertilizersinthe floodwater.
1. Additionallaborneeded.
2. Higher fi xationrateofphosphate.
3. Theplantsget “shocked” duetothe damagetoorbreakingofroots.
C. Injectioninto soil
5. Reducethedamagingandburningof theleaves.
6. Theminornutrientssuchasiron, copper,boron,zinc,andmanganesecan beeasilyappliedbyfoliarapplication.
7. Theinsecticidesarealsoappliedalong withfertilizersbyfoliarapplication.
1. Thelossofplantnutrientscanbe prevented.
2. Usedforcontrollingoreradicatingthe weeds.
3. Veryeffectiveandsaferforthe undergroundwaterintermsof contaminationandcausesnoorless healthhazards.
D. Aerial application
1. Usefulforhillyareas,forestlands,grass lands,sugarcane fields,etc.
2. Thelossoffertilizerisconsiderablylow inthismethod.
1. Lessnutrientlossandiswellcontrolled.
E. Fertigation
2. Boththewater-solublesolidandliquid fertilizerscanbeappliedalongwith irrigationwater.
Hill placement
Band placement
Basal application
Broadcasting
Top dressing
Row placement
Application of Solid fertilizers
Pellet application
Plough sole
Placement Deep placement
Localized placement
Fertilizersareappliedtocropsbothintheformofsolidsandliquids.Most ofthefertilizersareappliedintheformofsolids(e.g.,urea,diammonium phosphate,andpotassiumchloride).Solidfertilizeristypicallyusedin granulatedorpowderedform.Itisalsoavailableintheformofprillsorsolid globules[22].Liquidfertilizerscompriseanhydrousammonia,aqueous solutionsofammonia,andaqueoussolutionsofammoniumnitrateorurea. Theconcentratedliquidfertilizerscanbedilutedwithwater(e.g.,UAN). Itsmorerapideffectsandeasiercoveragearetheadvantagesofliquid fertilizer[9](Fig.1.1).
3.1Applicationofsolidfertilizers
3.1.1Broadcasting
Thespreadingoffertilizeralloverthe fieldinauniformmannerisknown asbroadcasting.Aseparateoperationinadditiontoseedingisrequiredin thebroadcastingmodeoffertilizerapplication.Thefertilizermaybespread onthesurfaceofthesoilitself,withorwithoutincorporationintothesoil, oritmaybeplacedbelowthesoilsurfaceincloselyspacedrowsbytheuse ofafertilizerdrill[8].
Normallythefertilizerusedforthiskindofapplicationisinaninsoluble form;especially,insolublephosphaticfertilizersuchasrockphosphateis usedforbroadcastingmodeofapplication.Thismethodissuitableforcrops withdensestand.Theplantrootswillpermeatethewholevolumeofthe soil.Largedosesoffertilizersareneededfortheapplication.
Therearetwomethodsofbroadcastingmethodofapplication,namely broadcastingatsowingorplanting(basalapplication)andtopdressing.
3.1.1.1Broadcastingatsowingorplanting(basalapplication)
Themainobjectiveofthebasalapplicationistheapplicationoffertilizersat sowingtimeforauniformdistribution.Thusthefertilizerwillbespread overtheentire fieldandcompletelymixwithsoil.
Figure1.1 Methodsofsolidfertilizerapplication.
Boronfertilizersaregenerallyappliedbybroadcastmethod.Normally theyareincorporatedpriortoseedingforcropsnotplantedinrows.Boron isappliedbybroadcastmethodinplantssuchaslegumesandgrassesand broadcastmethodsaremoreeffectiveintreesandgrapevinesandalsointhe casesofcoarser-texturedsoils[23].
Blackshawetal.[24]reportedthatNuptakebygreenfoxtail throughoutthegrowingseasonwasoftengreaterfromsurfacebroadcast thanfromsurfacepoolsorpoint-injectedN.Tokeepabreastofincreasing population,thericeproductionofAsiamustbeincreasedupto2.2% 2.8% annually.TheefficiencyoffertilizerNcanbeincreasedbytheimprovementoftimingandapplicationmethods,particularlythroughthebetter incorporationofbasalfertilizerNwithoutstandingwater[25].
3.1.1.2Topdressing
Thenitrogenousfertilizersarenormallyappliedcloselyincropslikepaddy andwheat,withtheobjectiveofsupplyingnitrogeninreadilyavailable formtogrowingplants.Thiskindofapplicationofnitrogenfertilizeris knownastopdressing.
Toimprovericeyieldandthenitrogenavailabilitytotheplants,top dressingisrecommendedtothelowersoillayerforJaponicarice[26 28], newhighyieldingricevarietiessuchasIndicatype[29],andlargegraintype varieties[28,30].
Inthecaseofricevarieties,thetimingoftopdressingwithhigh nitrogen(HN)toproducehighriceyieldisnotfullyunderstood. Matsushima[26]observedthattopdressingat30daysbeforeheading(30 DBH)resultedinworseplanttypeandyieldreductionduetothe elongationofthelowerinternodesandupperleaves.InamodelexperimentwithJaponicatypevarietyKoshihikari,Matsuba[31]indicatedthat thetopdressingat30DBHdidnotelongatethelowerinternodes.Inthe caseofTakanari,anIndicavariety,thetopdressingat30DBHdid notworsentheplanttypebutdidincreasethesinksizeinhigh-yielding varieties[26].Fukushimaetal.[28]suggestedthatthenewtyperice varietyBekoaobawillincreaseitssinksizeandthericeyieldbytopdressing at30DBHorearlytopdressingleadingtoshortculmsanderectleaf.
InBangladesh,crystalureaisnormallyappliedastopdressing.Itdecreasesyieldbymisbalancingtheyieldcomponents.Usuallythisproblemis preventedbytheapplicationofsupergranulesofurea(USG);sincethe USGhavetheabilitytominimizethelossofNfromsoil,thuseffectively increasingupto20% 25%[32].
Disadvantagesofbroadcasting:Theplantsinthe fieldcannotfullyutilize thefertilizersastheymovelaterallyoverlongdistances.Duetothepresence offertilizeralloverthe field,theweedsalsoabsorbthenutrientsandthe weedgrowthisalsostimulatedbythefertilizer.Largeamountofthefertilizerisneededandnutrientsare fixedinthesoil.Theymaycomein contactwithalargemassofsoil.
3.1.2Placement
Theplacementofthefertilizerinsoilataspecificplacewithorwithout referencetothepositionoftheseedisreferredasplacementmethodof fertilizerapplication.Theplacementmethodisnormallyrecommendedin conditionswherethequantityofthefertilizerissmallandthesoilhaslow fertility.Itcanbeappliedalsoincaseofplantswithpoorlydevelopedroots. Thephosphaticandpotassicfertilizersarenormallyappliedbyplacement method.
Thecommonlyusedmethodsofplacementmethodsareplowsole placement,deepplacement,andlocalizedplacement.
3.1.2.1Ploughsoleplacement
Duringtheprocessofploughing,thefertilizerisplacedatthebottomofthe ploughfurrowintheformofacontinuousbandsothateverybandis coveredasthenextfurrowisturned.Thismethodissuitablefordryland wherethesurfacesoilsbecomesquitedryuptoafewcentimetresfromthe bottomsoilandhaveaheavyclaypanjustbelowtheploughsolelayer.
3.1.2.2Deepplacement
Itisusedfortheplacementofammoniacalnitrogenousfertilizersinthe reductionzoneofthesoil,particularlyintherootzone.Thismethodis especiallysuitableforpaddy fields.Themainadvantageofthismethodisto preventthelossofnutrientsbyrun-off.
TheJapaneseuseddifferentmethodsofNfertilizerapplicationto minimizethelossofNthroughvolatization,denitrification,leaching,etc. BasedontheJapaneseconceptofdeeppointplacementoffertilizerNin transplantedrice,IFDC(InternationalFertilizerDevelopmentCenter) implementedtheuseofsupergranulesofurea(USG)toachievethesame agronomicbenefitsin1975[33].
Thelossofnitrogenisgreaterinrice(Oryzasativa L.) fieldsespeciallyin theirrigatedricecroppingsystemswithverypoorwatercontrol.Bandaogo etal.[34]conducted fieldexperimentsonSourouValleyinBurkinaFasoof
WestAfricaonthewetseasonof2012anddryseason2013.Thestudies werebasedontheeffectoffertilizerNintheformofprilledureawhichis appliedbybroadcastingandbriquettesintheformofUSG,whichisapplied byFDP(fertilizerdeeppointplacement).TheresultsindicatedthatFDPis genotypeandseasonspecificanditcanbesuggestedasanalternative methodforthefarmerstoimprovenitrogenuseefficiency(NUE)inthe irrigatedricecroppingsystem.
Nitrogenisfoundtobeanessentialnutrientforthegrowthoftherice plants.Usuallyprilledurea(PU)wasappliedbybroadcastingbecauseitis consideredasafastreleasingsourceofnitrogen.Butin floodedrice fields,it canbelostbyammoniavolatization,immobilization,denitrification,and surfacerunoff[35].Toovercomethisproblem,theUSGcanbeapplied bydeepplacement.USGisaslow-releasingnitrogenousfertilizerandit reducestheNlossandalsoimprovestheNuseefficiencyofwetland rice[36].
CraswellandDeDatta[37]recommendedthattheapplicationofurea supergranulesupto10cmdepthbydeepplacementmethodminimizesthe lossofN.Thebroadcastingofthesameatthesoilsurfacelevelcauseslosses upto50%.Theureasupergranulescanbealsoplacedintherootzone.This kindofapplicationalsoincreasesthericeyieldandnitrogenuseefficiency oftheplants[36,38].
Rogeretal.[39]studiedtheeffectofvariouskindsofnitrogenfertilizer applicationonthealgal floraandalsoaboutthebiologicalnitrogen fixation (acetylene-reducingactivity)inawetlandricesoilbybothpotand field analysis.Accordingtothem,thedeepplacementofUSGisfoundtobe betterthanthebroadcastapplicationofurea,sincethebroadcastapplication ofureainhibitedthenitrogen fixationbyfavoringthegrowthofthegreen algae.However,thedeepplacementofUSGdoesnotreportanynegative effectonthenitrogen fixingblue-greenalgae.Ontheotherhand,it permitsacetylenereducingactivityonthesoilsurfaceanditdoesnotinhibit thegrowthofnitrogen fixingbacteria.
3.1.2.3Localizedplacement
Inordertosupplythenutrients,adequateamountoffertilizerisappliedto thesoilclosetotheseedortotherootsofgrowingplants.Thecommon methodsusedfortheplacementoffertilizersornutrientsare:
3.1.2.3.1Drilling Inthismethodaseed-cum-fertilizermodeofdrillingis usedfortheapplicationoffertilizerduringthesowingtimeitself.The
fertilizerandtheseedareplacedinthesamerowbutthedepthisdifferent. Themethodissuitableinthecaseofcerealcrops,especiallyforthe applicationofphosphaticandpotassicfertilizers.Duetothehigher concentrationofthesolublesalts,thegerminatedseedsandyoungplants maygetdamaged.Thisisthegreatestdisadvantageofthismethod.
3.1.2.3.2Sidedressing
Thefertilizersarespreadbetweentherowsand aroundplants.Inthecaseofcropslikemaize,sugarcane,cotton,etc.,the fertilizerisappliedbyhandinbetweentherows.Butthefertilizersare placedaroundthetreeslikemango,apple,grapes,papaya,etc.Adiahaand Agba[40]foundoutthatamongthefourmethodsused(broadcasting,ring application,holeapplication,andliquidapplication)forthecultivationof maizeplants(Zeamays L.),ringmethodseemstobeappropriateformaize productionat1mspacingbetweenplantsonbed.
Advantagesofplacementoffertilizers:
Themainadvantagesofplacementmodeoffertilizerapplicationsareas follows:
(1) Thereisminimumcontactbetweenthesoilandthefertilizer.
(2) The fixationofnutrientisgreatlyreduced.
(3) Thenutrientsareavailableonlyforthecropplantsandtheweedsall overthe fieldcannotmakeuseofthefertilizers.
(4) Higherresidualresponseoffertilizers.
(5) Higherutilizationoffertilizersbytheplants.
(6) Lossoffertilizer,forexample,lossofnitrogen,byleachingisreduced.
(7) Immobilephosphatesarebetterutilizedwhenplaced.
3.1.3Bandplacement
Thebandplacementreferstothefertilizerplacementintheformofbands. Inthecaseofbandplacement,thefertilizerscanbeappliedbyhill placementmethodorbyrowplacementmethod.
3.1.3.1Hillplacement
Thefertilizerisappliedclosetotheplantsononeorbothsidesoftheplants asbandsbutthelengthandthebreadthofthebandisvariedwiththenature ofthecrop.Thismethodiscommonfortheapplicationoffertilizersin orchards.
Ibrahimetal.[41]reportedthatthehillplacementofmanureand fertilizerslikeDAP(diammoniumphosphate)andNPKimprovedtheyield andefficiencyofmilletsinSahelianagro-ecologicalareaofNiger.
3.1.3.2Rowplacement
Thefertilizerisappliedincontinuousbandsononeorbothsidesoftherow inwhichtheplantsareplanted.Thismethodiscommoninthecaseof cropslikesugarcane,potato,maize,cereals,etc.
Therewillbeafertilizerattachmentontheplanterincasesofhillorrow placement.Sothereisnoneedforaseparateoperation.Thesemethodsare laborsavingandinsomerarecases,theseedsandthefertilizerwillbe incorporatedinsoilseparatelybyusingmachineorbyhand[8].Under drierconditions,smallgrainsoffertilizershavebetterresponsetoband applications[42].
Themaximumuptakeofappliednutrientsdependsonthezoneof nutrientconcentrationandrootactivity[43].ChaudharyandPrihar[44] observedthatifthefertilizerwasplaced20cmbelowtheseeds,thenutrient uptakewasfoundtobeincreasedandtheseedlinggrowthwasalsofoundto befasterandresultedinhighergrainyieldinthecaseofmaize(Zeemays L.) andwheat(Triticumaestivum L.).Thisresultindicatesthatthebandplacementismoreeffectivethanthebroadcastmodeoffertilizerapplication.If thegrowthsoftherootsarefoundonlyinthesurfacelayers,itisadvised thatthefertilizershouldnotbebroadcastedtoavoidsurfacedrying.
Theobservationsin Oryzasativa L.madebyCaoetal.[45]revealedthat theseasonalchangelikethedriftingofdryseasonintowetseasonmayalso affectthemodeofapplicationoffertilizer.Theresultshowedthatthe uniformplacementandthepointplacementofUSGgavethehighestyield (6.4Mg/Ha)withefficiencyof51kgroughrice/kgNinthedryseason.At thesametime,inwetseason,bypointplacementwithUSGproduced highestyieldof4.4Mg/Hawithefficiencyof40kgroughrice/kgN.The recordsofthericecropatharvest,bothfromgrainandstrawsuggestedthat thefertilizerNuptakewashighas75%indryseasonand65%asinwet season.
3.1.4Pelletapplication
Itismainlyusedfortheplacementofnitrogenousfertilizersinthepaddy fields.Thefertilizersareappliedintheformofpelletsofabout2.5 5cm deepbetweenthecrops.Thesmallpelletsofconvenientsizesoffertilizers aremadeandmixedwiththesoilintheratioof1:10.Thepelletsare depositedinthemudofpaddy fields.
Schnieretal.[46]conductedastudyintransplantedriceanddirectseedfloodedricetoevaluatetheeffectoftimeandmethodoffertilizerN applicationongrainyieldandN-useefficiencybyusing 15Nlabeledurea.
Theconventionalapplicationofmethodsincludingbroadcastingand incorporationwerecomparedwithbandplacementofliquidureaandpoint placementofUSGs.Thestudyindicatedthatthebandorpointplacement resultsinsignificantlygreatergrainyieldwithsignificantreductioninthe partialpressureofNH3(pNH3)in floodwater.
IncreaseduseofNfertilizersinagriculturalpracticesmostlyresults inenvironmentalcontaminationbyleachingNintoplant-soilsystem. Reza-Bhagerietal.[47]conducteda fieldexperimenttostudytheeffectof pelletfertilizerapplicationincorn fields.Accordingtothem,theuse ofpelletformoffertilizerisanalternativeandbettermethodforthe applicationofNtothecorn fieldwhichresultsinmaximumgrainyieldand highestgrainproteincontent.TheNapplicationintheformofpellet releasesitscontentslowlyandduetocontinuousnutrientrelease,theplant canuptakeNatdifferentstagesofitsgrowth.
3.2Applicationofliquidfertilizersandwater-soluble granularfertilizers
Liquidfertilizersandwater-solublegranularfertilizerscanbeappliedbythe followingmethods:
3.2.1Startersolutions
AsolutionofN,P2O5,andK2Ointheratioof1:2:1and1:1:2appliedto youngvegetableplantletsparticularlyatthetimeoftransplantation isnormallyreferredtoasstartersolution.Thismethodhelpsinrapid establishmentandquickgrowthoftheseedlings.Theadditionallaborand higher fixationrateofphosphatesarethetwomajordisadvantagesofstarter solutionmethodoffertilizerapplication.
Duringthetimeoftransplantationofplants,theplantsget “shocked” duetothedamagedorbrokenroots.Asaresult,theuptakeofwaterand nutrientsbytherootswillberestrictedandstuntedgrowthordeathofthe plantsmayoccur finally.Replacingtheuseofpurewaterwithdilute solutionscontainingplantnutrientsoftenreducestheshockoftransplanted plantsresultinginfasterestablishmentofplants[48].
To findoutthebestcropmanagementpracticeswithstartersolutions, Susilaetal.[49]plantedchillipepperplants(Capsicumannuum L.)in polyethylenemulchedoninceptisolsoilwithpHof5.5,loworganic (1.54%),Ncontentof0.12%(verylow),Kcontentof0.29me(100g)-1, butwithveryhighsoilP205 concentration(19.2ppm)concentration. Theplantswerealsotreatedwithcowmanure,organicstartersolutions,
inorganicstartersolutions,andstandardinorganicfertilizer.Theresult indicatedthattheapplicationofcowmanure,standardinorganicfertilizer, ororganicstartersolutionsreducedtotalunmarketableyield,enhancedthe fruitquality,andimprovedmarketableyield.
TheAVRDC,2004(AsianvegetableResearchandDevelopment Center,Shanhua,Taiwan)reportedthatthesupplementationofliquid NPK(nitrogen,phosphorous,andpotassium)asstartersolutionsenhance theearlygrowthofcherrytomatoesandcabbagesgrownbyusingorganic fertilizers.Theyfoundthatthisisaneffectivetechnique,ie.,theapplication ofliquidfertilizeralongwiththeorganicfertilizerbecauseitenhancesN,P, Kuptakesbytheroots,increasesplantdryweight,andalsopromotesthe earlygrowthofthecropswithearlyfastgrowthrates.Theyconcludedthat thestartersolutionsmayacceleratetherootgrowthandtherebyincrease theefficiencyofabsorbingmorenutrientsfromsoilandorganicfertilizers.
GordenandPierzynski[50]foundthattheuseofstartersolutions containingNandPconsistentlyincreasedgrainyields,reducedthenumber ofthermalunitsrequiredforplantemergencetomaturity,decreasedgrain moisturecontentatthetimeofharvest,andincreasedtotalPuptakeof corn.
3.2.2Foliarapplication
Theapplicationofliquidfertilizersdirectlytotheleafsurfacebyusing sprayingmethodisknownas foliarapplication.Theleavescaneasilyand directlyabsorbthenutrientsthroughtheirstomatalopeningsandalso throughtheepidermis.Thiswillbeaneffectivemethodoffertilization[51]. Thefertilizersolutionscontainingoneormorenutrientswillbeappliedon thefoliageofthegrowingplants.Sincethenutrientsaresprayedonly afterdissolvingtheminwater,theleavescaneasilyabsorbseveralnutrient elements.Theconcentrationofthefertilizersolutioncanbecontrolled manuallyandthiswillreducethedamagingandscorchingoftheleaves. Theminornutrientssuchasiron,copper,boron,zinc,andmanganesecan beeasilyappliedbyfoliarapplication.Theinsecticidesarealsoappliedalong withfertilizersbyfoliarapplication.Foliarfertilizerscanbeapplieddirectly totheleaves.Thewater-solublestraightnitrogenfertilizersarealsousedfor foliarapplication.Itisespeciallyusedforhighvaluecropssuchasfruits[9].
TofacilitatetheoptimalNmanagement,ureacanbeappliedbyfoliar application.Thismodeofapplicationincreasesyieldandminimizestheloss ofNtotheenvironment[52].Theplantshavetheabilitytoabsorbfoliar appliedurearapidlyandhydrolyzetheureaincytosol[53,54].Thusthe
foliarappliedureaasNsourceisacommonpractice[55,56].Theseason [57,58]andthephysiologicaleffectscausedbythefoliarappliedureaasN sourcemayvarywiththecultivar[59].
Thefoliarappliedureainducesapositiveeffectinthewheatcultivation byincreasingthephotosyntheticrateandureaseenzymeactivities.Butin thecaseofsoybeans,theyieldswereinconsistentdependingontheyearand cultivarusedbythefoliarapplication[59].
NicoulaudandBloom[53]observedthatfoliarappliedureapromoted thegrowthofT-5tomatoes(Lycopersiconesculentum Mill.cv.T5)becauseit absorbed75%oftheureaappliedwithin12hand99%within24hof application.Theresultsconcludedthat(a)thefoliarappliedureacansupply therequiredNtosustainthegrowthoftheseedlings,(b)toalleviatetheN deprivation,theappliedureaisabsorbedbytheseedlingsasfastaspossible, (c)thefailureinthepromotionofrapidgrowthbyureaisprobablydueto phytotoxicity.
Heumannetal.[60]preparedasustainedreleasefertilizercomposition.In this,thewater-solublegranularfertilizersaresubjected firsttoaccretive granulationunderaccretivegranulationconditionswithameltsolutionor slurryofoneorseveralfertilizers.Asecondstagecoatingsuppliedthese treatedgrainswithasuitablealmostimpermeableenvelopment.Inthis processthegranulesaresubjectedtovariousconditionsoftemperatureand accretionunderwhichtheycanberegranulated.Theconditionswill bedependinguponthechemicalcompositionandthesizeofthewatersolublegranulesbeingtreatedandtheintendedmethodofaccretivegranulation.Oneormorepreponderantlywater-solublefertilizercomposition suchasurea,ammonium-,potassium-,NP-,NK-,PK-,orNPK-fertilizers canbeusedinthegranularpreparation.Thefertilizersthataretreated includethosepreparedfromconventionalmethodssuchascrystallization, pelletizing,graining,crushing,pressing,orspraydrying.Particularly contemplatedcompositionsfortreatmentincludefertilizerprills[61].
Thezincdeficiencyofthesoilcanbecorrectedbyfoliarsprayingandit willresultintheimprovementinthegrowthoftheplant,yield,andseed quality[62,63].Thaloothetal.[64]reportedthatfoliarsprayingwithzinc resultedintheimprovedyieldofthesunflowerplants.Gobarahetal.[65] concludedthatthefoliarapplicationof1.00g/LzincandP2O5/fad (phosphorouspentoxide)enhancedthegrowth,yield,andseedqualityof thegroundnuts.
Thelime-inducedirondeficiencychlorosisincitrusplantscanbe treatedbyfoliarsprayingofironcompounds.Thephotosynthesisand peroxidaseactivitycanalsoberestoredbythetreatment[66].
3.2.3Injectionintosoil/plants
Theliquidfertilizerscanbeinjectedintothesoilbyeitherpressureor nonpressuretypes.Nonpressuresolutionsmaybeappliedonthesurfaceor infurrows.Thelossofplantnutrientscanbepreventedbytheinjectionof liquidfertilizersintothesoil.Forexample,anhydrousammoniaplacedin narrowfurrowsatadepthof12 15cmwillbecoveredsuddenlyto preventlossofammonia.
Theplantrootstakeuponlyaverysmallportionofsoil-added fertilizers.Inmostofthecases,highsoilpermeabilityallowsthelossof nutrientsespeciallybyfastleachingofthefertilizerstotheunderground water[67].Thefertilizersarealsolostbyvolatization,especiallyN[68]. Theadditionofnutrientslikephosphorousandmicronutrientsintheform ofdissolvedcompoundsalsopreventstheabsorptionofaddedfertilizersby theroots[66].
Thefertilizersalsocanbedirectlyappliedtothetreetrunk.Themain advantageoftheinjectionoffertilizersdirectlyintotheplanttrunkisthe treatmentsusedforcontrollingoreradicatingtheweedscanbeavoided becausetheweedscannotcompetewiththecropplantsfortheavailable nutrients.Shaaban[10]recommendedtheapplicationofinjection fertilization,especiallydirectlytotrunksofmangoandgrapevine.Itisa veryeffectivemethodforthenutrientsupplyaswellasfoundtobesaferfor theundergroundwaterintermsofcontaminationandcausesnoorless healthhazards.
3.2.4Aerialapplication
Theapplicationofliquidfertilizerusingaircraftinareaswhereground applicationisnotpossibleisknownas aerialapplication;forexample,inhilly areas,forestlands,grasslands,sugarcane fields,etc.Thelossoffertilizeris considerablylowinthismethod.
Theaerialapplicationofsuperphosphatein Pinusradiata ofForest ResearchInstituteinNewZealandrecommendedthattheapplicationof fertilizersbyairplaneisanacceptedtoolofmanagementof P.radiata on phosphatedeficientsoilsandhavethebenefitsofoptimumtime,rate,and frequencyofapplication[69].
3.2.5Fertigation
Therearetwotypesofirrigationpracticesusedfortheapplicationoffertilizersalongwithirrigation,ie.,pressurizedirrigationanddripirrigation. Themajordisadvantageofnormalirrigationpracticeistheefficiencyof wateruseinthismodeislow.Butpressurizedirrigationpracticesnormally havehigherwateruseefficiency,lessnutrientloss,andarewellcontrolled. Theinitialcostandmaintenancecostsandexpertisearethemajorconstraintsofthepressurizedirrigationpractices.Themostappropriatemethod ofwaterandnutrientapplicationisthedripirrigationorfertigation[70].
Boththewater-solublesolidorliquidfertilizerscanbeappliedalong withirrigationwater.Thecombinedapplicationofwater-solublesolidor liquidfertilizerswithirrigationwaterthroughpressurizedirrigationsystem isknownasfertigation.Thenitrogenousfertilizerssuchasureaandother ammoniacfertilizerswhichareeasilysolubleinwaterareappliedalongwith irrigationwater.Theapplicationoffertigationwillincreaseyieldand minimizesoilandwaterpollution.Thelossoffertilizerisconsiderablylow inthismethod[71].
Thenutrientadditionbyfertigationisdeterminedbytheconcentration ofthenutrientsinirrigationwater,thenutrientabsorptionbytheplant,the rateofevapotranspiration,andthereaction(precipitationor fixation)bythe growthmedium[11].
Hebbaretal.[72]studiedtheeffectoffertigationandevaluatedthe sourcesandleveloffertilizerapplicationongrowth,yield,andfertilizeruse efficiencyofhybridtomatoinredsandyloamsoil.Thedatashoweda significantlyhigherproductionoftotaldrymatter(TDM)andleafarea index(LAI).Thechlorophyllconcentrationwassignificantlyhigherin fertigationtreatmentsandalsoresultedinlesserleachingofNO3-NandK. RootgrowthanduptakeofNPKwasalsoincreasedbyWSF(watersolublefertilizer)fertigation.Thecommonlyusedfertigationsystemsare pressuredifferential,theVenturi(vacuum),andinjectionpump.
InCalifornia,inthelate1960s,about5%ofthenitrogenfertilizerswere appliedwithirrigationwater[73].AchemigationsurveyinUSAconducted byThreadgill[74]showedthatonly3.5%ofthemusednitrogenfertilizers alongwithirrigationwater.Sixty-onepercentusedmicro-irrigationsystemsand43%usedsprinklersystems.
4.Thecontrolled-releasefertilizers
Bytheconventionalmethodsoffertilizerapplication,thenitrogenfertilizer isnotfullyabsorbedbythecropplants.Itwillmigratetothewaterbodies
leadingtonutrientenrichmentandcausenegativeimpactsonenvironmentalquality,ecosystemservices,andbiodiversity[75 77].Therehas beenmuchresearchconductedontechnologiestoimprovefertilizer applicationpracticesandeliminateadverseimpactsonwaterecosystems [78 83].
Controlled-releasefertilizersareencapsulatedinashellthatdegradesata specifiedrate.Thecommonlyusedencapsulationmaterialissulfur.Thermoplasticsandsometimesethylene-vinylacetateandsurfactantscanbeused asacoatingmaterialtoproducediffusion-controlledreleaseofureaorother fertilizers.Theuseofreactivelayercoatingcanproducethinnerand cheapermembranecoatingsbyapplyingreactivemonomerssimultaneously tothesolubleparticles.Thepracticeofapplicationoflayersoflow-cost fattyacidsaltswithaparaffintopcoatiscalled Multicote [7].
5.Slow-andcontrolled-releasefertilizers
Mostslow-releasefertilizersarederivativesofurea.Thisisakindofstraight fertilizerprovidingnitrogen,e.g.,Isobutylidenediurea(IBDU)andureaformaldehyde.TheyslowlyconvertNinthesoiltofreeurea,whichis rapidlytakenupbyplants.IBDUisasinglecompoundwiththeformula (CH3)2CHCH(NHC(O)NH2)2 whereastheurea-formaldehydesconsistof mixturesoftheapproximateformula(HOCH2NHC(O)NH)nCH2.They aremoreefficientintheutilizationoftheappliednutrients;thesetechnologiesreducetheimpactontheenvironmentandthecontaminationof thesubsurfacewater.Slow-releasefertilizersareappliedinvariousforms includingfertilizerspikes,tabs,etc.Theuseofslow-releasefertilizers reducestheproblemof “burning” theplantsduetoexcessnitrogen[7].
Theslow-andcontrolled-releasefertilizershavemanydisadvantages. Duetotheantagonisticpropertyoftheslow-andcontrolled-releasefertilizers,theirpracticalapplicationsinvolveonly0.15%(562,000tons)ofthe fertilizermarket.Eventhoughtheyprovidenutritiontoplants,excessfertilizerscanbepoisonoustosomeplantsandmayresultinthedegradationor lossofthefertilizer.Also,microbesdegrademanyfertilizersbyimmobilizationoroxidation.Theycanalsobelostbyevaporationorleaching[7].
6.Chemicalsthataffectnitrogenuptake
Theefficiencyofnitrogen-basedfertilizerscanbeenhancedbytheaddition ofvariouschemicals,andtherebythefarmerscanlimitthepollutingeffects
ofnitrogenrunoff.Nitrificationinhibitorsornitrogenstabilizerssuppress theconversionofammoniaintonitrate,ananionthatismoreproneto leaching.1-Carbamoyl-3-methylpyrazole(CMP),dicyandiamide,nitrapyrin(2-chloro-6-trichloromethylpyridine)and3,4-dimethylpyrazole phosphate(DMPP)arethepopularinhibitorsofnitrification[84].
Thehydrolyticconversionofureaintoammonia,whichisproneto evaporationaswellasnitrification,issloweddownbytheuseofurease inhibitors.Theureasesareenzymesthatcatalyzetheconversionofureato ammonia.ExampleofureaseinhibitorisN-(n-butyl)thiophosphorictriamide(NBPT).
7.Overfertilization
Excesscaremustbetakenwhileusingthefertilizerbecauseexcessfertilizers canbedetrimentaltoplants.Fertilizerburnwilloccurwhenexcessfertilizer isappliedthatwillresultindamageorevendeathoftheplant[61].
8.Conclusion
Inearlierdays,researcheswerefocusedmainlyonmaximizingyield.But thepresentresearchesaimatsatisfyingtheevergrowingdemandforfood andmaintainingthequalityoffoodbymaximizingthequantityandquality ofyieldswithoutneglectingtheenvironment.Theneedtoimprovethe fertilizerefficiency,particularlyNfertilizerefficiency,isthemajorissue facedbytheagriculturalpracticesworldover.Oneofthemajorcausesof theenvironmentalpollutionistheexcessuseofthefertilizers.Fertilizerand plantnutritionresearchshouldbeestablishedtopreventtheenvironmental pollutionandatthesametimemeettheproductivityandyieldrequirements.Controlled-releasefertilizers,banddeepplacementmethods, foliarapplication,andminimumtillagemethodscanbeusedtoimprovethe efficiencyofNfertilizersandshouldbeimprovedandrefinedtoreducethe environmentalcontamination[70].Modernagriculturalpracticeswillbe instrumentalindevisingsuchpreciserecommendations,whichminimize transportofnutrientsontounwantedsitesandgeneratehighyields economically,withemphasisonthepreservationofcleanenvironment.
References
[1]H.Kiiski,H.W.Scherer,K.Mengel,G.Kluge,K.Severin,Fertilizers,1.general,in: Ullmann’sEncyclopediaofIndustrialChemistry,2000,pp.1 30.
[2]T.I.Williams,AShortHistoryofTwentieth-CenturyTechnologyC.1900-c.1950, OxfordUniversityPress,1982,ISBN978-0-19-858159-8,pp.134 135.
[3]A.J.Ihde,TheDevelopmentofModernChemistry,CourierCorporation,1984,ISBN 978-0-486-64235-2,p.678.
[4]J.W.Erisman,M.A.Sutton,J.Galloway,Z.Klimont,W.Winiwarter,Howacentury ofammoniasynthesischangedtheworld,Nat.Geosci.1(10)(2008)636 639.
[5]A.D.Glass,Nitrogenuseefficiencyofcropplants:physiologicalconstraintsupon nitrogenabsorption,Crit.Rev.PlantSci.22(5)(2003)453 470.
[6]C.P.Vance,C.Uhde-Stone,D.L.Allan,Phosphorusacquisitionanduse:critical adaptationsbyplantsforsecuringanonrenewableresource,NewPhytol.157(3)(2003) 423 447.
[7]P.Weerasinghae,K.Prapagar,K.M.C.Dharmasena,NitrogenReleasePatternsofUrea andNanoUreaFertilizerUnderTwoContrastingSoilMoistureRegimes,2016.
[8]R.M.Salter,MethodsofApplyingFertilizers,USDepartmentofagriculture,1938.
[9]H.Dittmar,M.Drach,R.Vosskamp,M.E.Trenkel,R.Gutser,G.Steffens,Fertilizers, 2.Types,in:Ullmann’sEncyclopediaofIndustrialChemistry,2009.
[10]M.M.Shaaban,Injectionfertilization:afullnutritionaltechniqueforfruittreessaves 90-95%offertilizersandmaintainsacleanenvironment,FruitVeg.CerealSci. Biotechnol.3(1)(2009)22 27.
[11]J.Hagin,A.Lowengart,Fertigationforminimizingenvironmentalpollutionby fertilizers,in:FertilizersandEnvironment,Springer,Dordrecht,1996a,pp.23 25.
[12]B.Borghi,Nitrogenasdeterminantofwheatgrowthandyield,in:Wheat:Ecology andPhysiologyofYieldDetermination,FoodProductsPress,NewYork(USA),1999, pp.67 84.
[13]K.Blankenau,H.W.Olfs,H.Kuhlmann,Strategiestoimprovetheuseefficiencyof mineralfertilizernitrogenappliedtowinterwheat,J.Agron.CropSci.188(3)(2002) 146 154.
[14]L.López-Bellido,R.J.López-Bellido,R.Redondo,Nitrogenefficiencyinwheat underrainfedmediterraneanconditionsasaffectedbysplitnitrogenapplication,Field CropsRes.94(1)(2005)86 97.
[15]F.G.Viets,ThePlant’sNeedforandUseofNitrogen,1965,pp.503 549.Soil nitrogen.
[16]J.H.G.Slangen,P.Kerkhoff,Nitrificationinhibitorsinagricultureandhorticulture:a literaturereview,Fert.Res.5(1)(1984)1 76.
[17]J.R.Freney,C.J.Smith,A.R.Mosier,Effectofanewnitrificationinhibitor(wax coatedcalciumcarbide)ontransformationsandrecoveryoffertilizernitrogenby irrigatedwheat,Fert.Res.32(1)(1992)1 11.
[18]R.Novoa,R.S.Loomis,Nitrogenandplantproduction,PlantSoil58(1 3)(1981) 177 204.
[19]H.A.Mills,J.B.JonesJr.,PlantAnalysisHandbookII:APracticalSampling, Preparation,Analysis,andInterpretationGuide,1996.No.581.13M657).
[20]J.B.JonesJr.,PlantNutritionandSoilFertilityManual,CRCpress,2012.
[21]V.Smil,EnrichingtheEarth:FritzHaber,CarlBosch,andtheTransformationof WorldFoodProduction,MITpress,2004.
[22]R.J.Haynes,R.Naidu,Influenceoflime,fertilizerandmanureapplicationsonsoil organicmattercontentandsoilphysicalconditions:areview,Nutr.Cycl.Agroecosyst. 51(2)(1998)123 137.
[23]D.C.Martens,D.T.Westermann,FertilizerApplicationforCorrectingMicronutrient Deficiencies,1991.
[24]R.E.Blackshaw,G.Semach,H.H.Janzen,Fertilizerapplicationmethodaffects nitrogenuptakeinweedsandwheat,WeedSci.50(5)(2002)634 641.
[25]S.K.DeDatta,ImprovingnitrogenfertilizerefficiencyinlowlandriceintropicalAsia, in:NitrogenEconomyofFloodedRiceSoils,Springer,Dordrecht,1986, pp.171 186.
[26]S.Matsushima,Technologyforimprovingricecultivation,Yokendo,Tokyo,1973, pp.1 393.
[27]A.Fukushima,Effectsoftimingofnitrogentopdressingonmorphologicaltraitsin differentricevarieties,Jpn.J.CropSci.76(2007)18 27.
[28]A.Fukushima,H.Shiratsuchi,H.Yamaguchi,A.Fukuda,Effectsofnitrogen applicationandplantingdensityonmorphologicaltraits,drymatterproductionand yieldoflargegraintypericevarietyBekoaobaandstrategiesforsuperhigh-yieldingrice intheTohokuregionofJapan,PlantProd.Sci.14(1)(2011)56 63.
[29]Y.San-Oh,Y.Mano,T.Ookawa,T.Hirasawa,Comparisonofdrymatterproduction andassociatedcharacteristicsbetweendirect-sownandtransplantedriceplantsina submergedpaddy fieldandrelationshipstoplantingpatterns,FieldCrop.Res.87(1) (2004)43 58.
[30]T.Mae,A.Inaba,Y.Kaneta,S.Masaki,M.Sasaki,M.Aizawa,A.Makino, Alarge-grainricecultivar,Akita63,exhibitshighyieldswithhighphysiologicalN-use efficiency,FieldCrop.Res.97(2 3)(2006)227 237.
[31]K.Matsuba,Anewmorphogeneticmodelonthemostsuitableleaf-internodeunitand developmentalstageforcontrollingplanttypesinrice(Oryzasativa)cultivation,Jan.J. CropSci.(2000)(Japan).
[32]M.Hasanuzzaman,K.Nahar,M.M.Alam,M.Z.Hossain,M.R.Islam,Responseof transplantedricetodifferentapplicationmethodsofureafertilizer,Growth5(2009)6.
[33]N.K.Savant,P.J.Stangel,Deepplacementofureasupergranulesintransplantedrice: principlesandpractices,Fert.Res.25(1)(1990)1 83.
[34]A.Bandaogo,F.Bidjokazo,S.Youl,E.Safo,R.Abaidoo,O.Andrews,Effectof fertilizerdeepplacementwithureasupergranuleonnitrogenuseefficiencyofirrigated riceinSourouValley(BurkinaFaso),Nutr.Cycl.Agroecosyst.102(1)(2015)79 89.
[35]A.Sreenivasan,V.Subrahmanyan,Biochemistryofwater-loggedsoils.PartIV.Carbon andnitrogentransformations,J.Agric.Sci.25(1)(1935)6 21.
[36]M.S.Hasan,S.M.A.Hossain,M.Salim,M.P.Anwar,A.K.M.Azad,Responseof hybridandinbredricevarietiestotheapplicationmethodsofureasupergranulesand prilledurea,PakistanJ.Bio.Sci.5(7)(2002)746 748.
[37]E.T.Craswell,S.K.DeDatta,RecentDevelopmentsinResearchonNitrogen Fertilizersforrice.SoilandFertilizerForumofThailand,1980.
[38]S.K.Sharma,Presentstatusofintermediatetechnologyinriceproductionincludingthe possibleutilizationofbluegreenalgaeandazolla,paperpresentedattheAll-IndiaRice Workshop,heldattheDirectorateofRiceResearchRajendranagar,Hyderabadduring 12-15April1985,IndianJ.Asril.Sci59(3)(1989)154 156.
[39]P.A.Roger,S.A.Kulasooriya,A.C.Tirol,E.T.Craswell,Deepplacement:amethodof nitrogenfertilizerapplicationcompatiblewithalgalnitrogen fixationinwetlandrice soils,PlantSoil57(1)(1980)137 142.
[40]M.S.Adiaha,O.A.Agba,Influenceofdifferentmethodsoffertilizerapplicationonthe growthofmaize(Zeamays L.).forincreaseproductioninsouthNigeria,WorldSci. News54(2016)73 86.
[41]A.Ibrahim,R.C.Abaidoo,D.Fatondji,A.Opoku,Hillplacementofmanureand fertilizermicro-dosingimprovesyieldandwateruseefficiencyintheSahelianlow inputmillet-basedcroppingsystem,FieldCropsRes.180(2015)29 36.
[42]G.W.Randall,R.G.Hoeft,PlacementmethodsforimprovedefficiencyofPandK fertilizers:areview,J.Prod.Agric.1(1)(1988)70 79.
[43]N.K.Fageria,V.C.Baligar,C.A.Jones,GrowthAdMineralNutritionofFieldCrops, MarcelandDekker,1991.
[44]M.R.Chaudhary,S.S.Prihar,Comparisonofbandedandbroadcastfertilizerapplicationsinrelationtocompactionandirrigationinmaizeandwheat,Agron.J.66(4) (1974)560 564.
