Post on 20-Jul-2020
Making more effective zinc fertilizers
Mosaic-supported Fertilizer Technology Research Centre @ The University of Adelaide, Australia
Life Impact The University of Adelaide Slide 1
Zinc is an essential element for humans
l Humans,animals,plantsneedzinctofunction
l Affectsover300enzymesinthebody
l Supportsnormalgrowthanddevelopment
l Essentialformetabolismandcellulargrowth
l Especiallyimportantduringpregnancy,childhoodandadolescence
l Keyforimmunesystem
l Activateswoundhealingl Impactstaste,mood,hair,fingernails
Life Impact The University of Adelaide Slide 2
Zinc deficiency – a global Issue
l 2billionpeopleatriskofzincdeficiency
l 195millionchildren<5yearsatriskofstunting
l 2millionchildren<5yearsdieduetopneumonia
l 1.5millionchildren<5yearsdieduetodiarrhea
l 800,000deathsattributedtozincdeficiency
l 450,000children<5yearsdieduetozincdeficiency
l Subclinicalzincdeficiencyalsoprevalentindevelopednations
Life Impact The University of Adelaide Slide 3
l TheInternationalZincAssociation(IZA)incollaborationwithUNICEFhasaprogramtosupplementchildren’sdietswithZn
l IZAisalsosupportingpromotionofzinc-fortifiedfertilizersindeficientareas
Zinc is an essential element for humans
Life Impact The University of Adelaide Slide 4
Zinc nutrition of crops
l CropsrequireZninsmallamountstopromotephotosynthesis,seedproduction,growthregulationandforresistancetodisease
l DeficiencyofZnisaglobalproblemthataffectssoilsandcropsworldwide
l ThecrucialroleZnplaysinhumanhealthisnowrecognisedasaglobalissue
Life Impact The University of Adelaide Slide 5
Zn
Zn
Zn
Zn Zn
l highCaCO3l highpHl highclaycontentl highFeandAloxidesl lowsoilmoisture
Zn
SOIL
LimitedZnuptake
What limits crop Zn uptake from soils? FertilizerZn
SoilSolutionZn2+
ZnCO3
ZnCO3
Zn3(PO4)2
AdsorbedZnPrecipitatedZn
Life Impact The University of Adelaide Slide 6
Zinc nutrition of crops TherearetwomainfactorstoconsiderincropZnnutrition
l Placement-physicalaccessibilityofZninsoilforaccessbycroprootsystems
l Solubility-rateandextentofreleaseofZnfromfertilizertothegrowingcropinrelationtocropdemand
Life Impact The University of Adelaide Slide 7
Zinc fertilizers
ZnOorZnSO4-enrichedNPKgranularfertilizerse.g.MAP,DAP,MESZ
GranularZnforbulkblendingwithNPKfertilizers
Znpowdersforfertigationorfoliar(commonlyZnOorZnSO4)
Znchelatesforfoliarorfertigation
Life Impact The University of Adelaide Slide 8
Pure Zn fertilizers and solubility
l ThemostsolubleZnsourceisZnsulfate,usuallysoldasZnsulfateheptahydrate(23%Zn)whichhasawatersolubilityof~960g/L
l Zincoxide(ZnO)is80%Zn,buthasamuchlower(~200,000timeslower)watersolubility(1.5-5.0mg/L)thanZnsulfate
l WhenZnOdissolvesithasanalkalinereaction(byconsumingacid)–asH+ionsareneededfordissolution,whichcausesitslowsolubility:
ZnO(solid)+2H+èZn2+(solution)+H2O
Life Impact The University of Adelaide Slide 9
Pure Zn fertilizers and solubility
l Despiteitslowwatersolubilityinwater,ZnOcanbeeffectiveifuniformlymixedthroughoutsoil
l Thesoilprovidesa“pull”forZn,andcanstoppHincreasingaroundtheoxideparticleorprovideH+ions-allthesepromotedissolutionoftheoxide
l However,ifZnOisbandedorpresentaslargeparticles,itseffectivenessisreducedcomparedtoZnSO4becauseofreducedsurfaceareafordissolution,thealkalinereactionandthelowerabilityofsoiltosorbtheZn
Life Impact The University of Adelaide Slide 10
Pure Zn fertilizers and solubility
0
10
20
30
40
50
60
70
80
90
100
doubleband singleband surface uniform
PlantZ
nde
rived
from
fertilizer(%)
Placement
ZnO2
FP2
sulfate
e
f f
bc c
f
d
f
abababc aA
banded mixed
Life Impact The University of Adelaide Slide 11
l SegregationofpureZnfertilizersblendedwithothernutrients(e.g.N,P)resultsinpoordistributionofnutrientsinthefield
l Granulessegregateaccordingtoparticlesizeratherthandensity
l Particlesizesneedtobeidenticaltopreventgranulesegregation
Bulk blends of Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 12
Particlesizesegregationduringapplication
Bulk blends of Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 13
0
5
10
15
20
25
30
35
-2 -1 0 1 2
Distancefromtractorcentre(m)
Fertilizerd
istrib
ution(%
)
0.25-0.5mm
1-2mm
Granulesize
Source:Karnok(1986)TheSegregationofHomogeneousandBlendedGranularFertilizersfromaRotarySpreader,Agron.J.78:258-260
Ballisticsegregationfromrotaryspreaders
Bulk blends of Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 14
l TypicalratesofZnrequiredbycropsvaryfrom1to10kgZn/ha,generally2-3kg/ha
l AmountsofZnarelowandevenwithalowZncontentproducte.g.Znsulfateheptahydrate(23%Zn)thedistributionofZninsoilispoor
l Assumingnormalgranulesizeandbroadcastat2kg/ha,therewouldbeabout22Zngranules()persq.msoil
l Zincdoesnotdiffusefarfromthegranule–unlikelyplantrootswould“see”thisZneasily
Bulk blends of Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 15
l Co-granulatedNP+Znproductsaretypically0.5-1%Znl AssumingnormalgranulesizeandbroadcastZnat2kg/ha,
therewouldbeabout5001%Zngranulespersq.msoil–muchmorelikelyplantrootswould“discover”thisZn
l AlsoaplacementadvantagethatZnisclosetoNandPnutrients–rootswill“gothere”
Co-granulated Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 16
l Co-granulatedproductsoffersignificantplacementadvantagesoverpureZnfertilizersorbulkblendsofZnfertiliserswithothernutrients
Co-granulated Zn with macronutrient fertilizers
Life Impact The University of Adelaide Slide 17
Co-granulatedZn
Life Impact The University of Adelaide Slide 18
FertilizerZnefficiencyislowinco-granulatedproducts
Ni62Cu63Zn64Cu65Zn66Zn67Zn68Ga69/int
INTENSITY
67Znenrichedplant
<0.5%ofaddedfertilizerZntakenupinfirstyear
McBeath T.M., McLaughlin M.J., Kirby J.K., Degryse F. (2013) A stable isotope methodology for measurement of soil applied zinc fertilizer recovery in Durum wheat (Triticum durum). Journal of Plant Nutrition and Soil Science (in press).
Chromosol
Kandosol
Calcarosol
Sodosol0.0
0.1
0.2
0.3
0 2 4 6 8 10 12 14
Fertilizere
fficien
cy(%
ofadd
ed)
LabilesoilZn(mgkg-1)
Znadded/Znuptake=115
Znadded/Znuptake=20
Life Impact The University of Adelaide Slide 19
l ThesolubilityoftherawZnmaterialsusedtoco-granulatewithphosphaticfertilizersisnotofgreatimportanceforfinalZnwatersolubility
l Co-granulatingeitherZnsulfateorZnoxidewithNPfertilizersresultsinthesameformsofZninthefinalproduct–predominantlyZnphosphateorZnammoniumphosphate
Issues with co-granulating Zn in P fertilizers
3ZnO+2H3PO4⇔Zn3(PO4)2+3H2O
3ZnSO4+2H3PO4⇔Zn3(PO4)2+3H2SO4
Life Impact The University of Adelaide Slide 20
Issues with co-granulating Zn in P fertilizers l Theacidityatwhichgranulationisperformed(measuredbypH)controlstherelativeamountsofeachoftheseminerals
l WehavemeasuredZnmineralsinMESZusingsynchrotronx-raymethods
Life Impact The University of Adelaide Slide 21
l SpeciationofZninMicroessentialsandcompetitorgranules
Issues with co-granulating Zn in P fertilizers
Life Impact The University of Adelaide Slide 22
l Inco-granulatedproducts,releaseofZnfromthegranuleislimitedinmostsoilsduetotheinsolubilityofZnphosphate
l AMAP+Zngranulewasincubatedinsoilfor4weeksandZnmappedinandaroundthegranuleusingsynchrotronradiation
90% of Zn remained in co-granulated MAP + Zn, 4 weeks after application to soil
Issues with co-granulating Zn in P fertilizers
Life Impact The University of Adelaide Slide 23
l GranulechemistrycanaffecthowwatersolubleanddiffusibletheZnbecomesongranuledissolution
Issues with co-granulating Zn in P fertilizers
DAP+Zn MAP+S+Zn
GranulesplacedinsoilincentreofPetridishandmovementofZnfromgranuleevaluatedcolorimetrically
Life Impact The University of Adelaide Slide 24
Speciation of Zn and granule pH
Life Impact The University of Adelaide Slide 25
Water solubility of Zn and granule pH
Life Impact The University of Adelaide Slide 26
Hopeite (Zn3(PO4)2) mineral controls Zn solubility
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
3 4 5 6 7 8
Totaldissolved
Zn(M
)
pH
0.01MMAP
0.1MMAP
ZAP
hopeite
Life Impact The University of Adelaide Slide 27
Dissolution result
Rate of Zn release from granules
Life Impact The University of Adelaide Slide 28
What about Zn in potash?
Life Impact The University of Adelaide Slide 29
Agronomic effectiveness of Zn
R2 = 0.78
0
20
40
60
80
100
0 50 100Water soluble Zn (%)
Rel
ativ
e ag
rono
mic
ef
fect
iven
ess
(%)
ZnSO4ZnO
EarlyresearchfromMortvedtandGiordano(1969)demonstratedthathighwatersolubilityoffertilizerZnisneededforfast-growingannualcrops
Life Impact The University of Adelaide Slide 30
Agronomic effectiveness of Zn l WatersolubilityofZninthefertilizeristhekeyattribute
leadingtofertilizerefficiencyforannualcrops
l ThelinkbetweenZnspeciesinthefertilizerandwatersolubilityisnotstrong
l AkeyattributetocontrolisgranulepH
Low Medium High
Life Impact The University of Adelaide Slide 31
Controlling granule pH
TypicalGranulationwindow(MAP)
MESZWindow
Life Impact The University of Adelaide Slide 32
Increasing water soluble Zn in MESZ
l NeedtoretainflexibilityinoperatingplantwindowforpHtoallowgoodgranulation
l StrategiestoincreasewatersolubleZn
l PhysicallyseparateZnfromPcoreofgranulewithcoatingspostgranulation
l AddchelateseitherpriororpostgranulationtocomplexZnandreduceformationofhopeiteondissolution
l Addacidifyingagentspostgranulationtoimprovesolubilityofhopeite
Life Impact The University of Adelaide Slide 33
Barrier coatings to separate Zn from P
MAPgranule
Cu/Zncoating
“barrier”coating
USPOApplicationNumber61/309,894filed3March2010
Life Impact The University of Adelaide Slide 34
Zinc effectiveness in barrier-coated products
K-Mag+PEI SOP+PEI
ZnSO4
Urea+PEI
Amm.Sul+PEI
MAP-Zn
Life Impact The University of Adelaide Slide 35
Acidifying agents - products tested
PHOSPHATEFERTILISERSMESZwith1%Znwt/wtand2,3,4%acidcoatings
MOP-BASEDFERTILISERSAllwith1%Znwt/wtCompactedandCoated
MESZ+sulfamicacid MOPZnSO4
MESZ+oxalicacid MOPZnO
MESZ+citricacid MOPZnO+1.5%sulfamicacid
MESZ+peKacid MOP
MESZ(control)
Life Impact The University of Adelaide Slide 36
Sulfamic acid coated MESZ
MESZwith
WSZn(%)
TotalZn(%)
WS/Total(%)
pH(1:10)
2%acid 0.71 1.07 66.6 3.88
3%acid 0.79 1.09 71.9 3.67
4%acid 0.91 1.13 81.1 3.49
Life Impact The University of Adelaide Slide 37
Acidifying agents and Zn solubility
AcidifyingagentswereeffectiveinincreasingWSZn
Life Impact The University of Adelaide Slide 38
Acidifying/chelating agents and Zn diffusion
AcidifyingagentsandEDTAwereeffectiveinincreasingZndiffusionfromgranules
Life Impact The University of Adelaide Slide 39
Acidifying/chelating agents and Zn diffusion
CitricandsulfamicacideffectiveinincreasingZnsupplytoplantinadeficientsoil
Life Impact The University of Adelaide Slide 40
Zn response curve
0.100 0.50 1 5
1 23 4
5
0.25 1042
1-1.5
54-4.5 5
CourtesyIsmailCakmak,SabanciUniversity
Life Impact The University of Adelaide Slide 41
67.13MES10 67.1 67.4 67.3
12.5
2.5 - 3 33 -3.5
Score: 1 (bad) 5: very good
MESZuncoated
MESZ+SA2%
MESZ+OA2%
MESZ+SA4%
CourtesyIsmailCakmak,SabanciUniversity
Life Impact The University of Adelaide Slide 42
72.14 72.13 72.11 72.10
22 - 2.5 2.5 - 3
3.5 4
72.9
Score: 1 (bad) 5: very good
MAP+4%APP
MAP+2%APP
MAP+5%EDTA
MAP+2.5%EDTA
MAPuncoated
CourtesyIsmailCakmak,SabanciUniversity
Life Impact The University of Adelaide Slide 43
Co-compacted MOP products
MOP
WSZn(%)
TotalZn(%)
WS/Total(%)
pH(1:10)
1%ZnasZnSO41.14 1.17 98 5.79
1%ZnasZnO0.06 0.99 6 6.55
1%ZnasZnO+sulfamicacid 0.45 1.06 42 6.22CompactedMOP - -- 7.03
Life Impact The University of Adelaide Slide 44
Acidifying/chelating agents and Zn diffusion - MOP
SulfamicacideffectiveinincreasingZndiffusionfromZnOaddedtoMOP.
Life Impact The University of Adelaide Slide 45
Acidifying/chelating agents and Zn uptake - MOP
Life Impact The University of Adelaide Slide 46
8 9 3 2
12
3 - 3.54
5
10
Score: 1 (bad) 5: very good
MOP MOP+ZnOcomp.
MOP+1%ZnSO4+0.1%PEI
MOP+ZnOcoat
MOP+ZnOcoat+1%SA
CourtesyIsmailCakmak,SabanciUniversity
Life Impact The University of Adelaide Slide 47
Keeping Zn water solubility in perspective
l Fast-growingannualcrops(corn,wheat,soybean,canola,potato,etc.)intemperateanddrylandregionsrequirerapidZnsupplyfromsoil/fertilizer
l Perennialcrops(fruit,stonefruit,nuts,forestry)inhighrainfallenvironmentsrequirealowerrateofZnsupplyfromsoil/fertilizeroveralongerperiod
Life Impact The University of Adelaide Slide 48
Summary points
• Zincmustbeaddedtoeachgranuletoensureuniformdistributioninthefield–bulkblendsnoteffective
• HigherwatersolubleZnisdesirableforagronomicefficiencyofZnfertilizer
• FormofZnaddedtoPfertilizersorpresentinfertilizerisnotimportantasZn-phosphatecompoundsformingranuleandin/aroundgranuleondissolution
• GranulepHisastrongdeterminantofwatersolubilityandagronomicperformance
• UsinggranulationpHtocontrolwatersolubilityofZnisdifficultasthegranulationpHwindowisthenrestricted
Life Impact The University of Adelaide Slide 49
Summary points
• WatersolubleZninPfertilizerscanbeimprovedbyaddingchelatesoracidifyingagentspostgranulation
• ForMOPnoprecipitationofZnoccursin/onthegranuleandifasolubleZnsourceisused,dissolution/diffusionisrapid
• Acidifyingagents(e.g.sulfamicacid)canbeaddedtoimproveeffectivenessofZnOinMOP
• CoatingZnisbetterthanco-compaction• SmallamountsofPEIincreasedeffectivenessofZnSO4with
MOP
Life Impact The University of Adelaide Slide 50
Way forward
• ContinuetosearchformoreeffectivechelatesoracidifyingagentsforimprovingwatersolubilityofZn
• Seekgranulationaidstoallowawider(i.e.lower)pHwindowforeffectivegranulation
• Evaluatepromisingformulationsinfieldtrials
Life Impact The University of Adelaide Slide 51
Thank you for your attention! !