Field trials - Polysulphate

Compendium of

Field trials

®

Trial

BananaBrazilContent

2

®

Trial

Black pepperVietnamContentContent

By CropsBanana 4Black pepper 5Broccoli 6Cabbage 7Carrot 12Cauliflower 13Coffee 14Cotton 16Grass 17Green pepper 21Lucerne 22Maize 23Mustard 28Oilseed rape 29Onion 35PackChoi 37Peas 39Peanut 42Pineapple 43Pomegranate 44Pomelo 45Potato 46Rice 57Rocket 59Sesame 60Soybean 61Strawberry 65Sugarcane 67Tea 69Tomato 70Wheat 73

By CountryArgentina 23,24,62,74Brazil 4,7,61,63China 9,21,30,37,38, 44,45,47,66,70,71Colombia 46,54,65,68,72Ecuador 58France 6,12Greece 50India 11,13,28,60Italy 59Malaysia 43Mexico 27Paraguay 64Peru 52TheNetherlands 17-20,36,49,56Turkey 10,16,35UK 8,22,25,26,29, 31-34,39-41,51,73USA 48,53,55,57,67Vietnam 5,14,15,42,69 3

®

Trial

BananaBrazil

ObjectiveToevaluatetheeffectsubstitutingKClfertilizerwithPolysulphate as a source of K has on the yield and quality of banana.

TreatmentsThisrandomizedblocktrialconsistedoffourreplicateswitheighttreatments.DifferentblendsofKClandPolysulphateweretestedtosupply360kgK2O ha-1:1) Control,withoutKapplication2) 100% KCl3) 80%KCl+20%Polysulphate4) 60%KCl+40%Polysulphate5) 50%KCl+50%Polysulphate6) 40%KCl+60%Polysulphate7) 20%KCl+80%Polysulphate8) 100% Polysulphate

Thefertilizerswereappliedontothesoilsurfaceattwotimes:firstinNovember2016;secondinJanuary2017.100kgP2O5 ha-1 as MAP and 250 kg N ha-1asammoniumnitratewereapplied at the same time in all treatments.

Results• Polysulphate increased the vigor of bunches and slightly

increased the diameter of stems.• Partial replacement of KCl by Polysulphate increased crop

productivity.• TheKCl:Polysulphateblendswith50%to60%Polysulphate

ledtothegreatestincreases,eveninhighfertilitysoils.

Different letters above bars indicate significant differences among treatments(P<0.05)

From research funded by the International Potash Institute www.ipipotash.org.

25

26

5

27

28

6

29

7

30

8

9

10

Zero K2O 100% KCl 80% KCl+20%Poly

60% KCl+40%Poly

50% KCl+50%Poly

40% KCl+60%Poly

Yiel

d - t

/ha

Vigo

r

Yield Vigor

20% KCl+80%Poly

100% Poly

bc

ab

c

b

abc

ab

abc

abab

ab

ab

a

a

abc

ab

bc

WhenFertilizer application: November 2016Harvest: August 2017

WhereJuquia,SaoPaulostate,Brazil

CropBanana (Musa acuminata),Cavendish Subgroup

Soil typeUltisol,highclaycontent(430gkg-1 of clay)

Measurements• Yield • Vigor of bunches • Diameter of stems

BananaBrazil

+11%yield increase

as compared to control

4

http://www.ipipotash.org

®

Trial

Black pepperVietnam

ObjectiveToevaluatetheeffectivenessofPolysulphateasasupplementaryfertilizeronblackpepperperformance,yield,quality,andeconomicefficiencyundertheconditionsoftheCentral Highlands of Vietnam.

TreatmentsTheexperimentwassetaccordingtoarandomizedcompleteblockdesign(RCBD)withfourreplications.PolysulphatewasexaminedincombinationwithMOP(KCl),inequalproportions,toprovidedosesof120,240and360kgK2O/ha/yr,splitintosixapplicationsduringtheyear.Thesetreatmentswerecomparedtodosesofzero(control),120,and270(farmers’practice)kgK2O/ha applied solely as MOP. Standard N and P fertilizers wereappliedinalltreatments.

Results• Fruitweight,volumeanddensityincreasedwith

PolysulphateapplicationcombinedwithMOP,whilefruitshedding rates reduced.

• Elongation of primary branches and number of secondary branchesincreasedwithPolysulphateapplicationcombinedwithMOP,whileprematurefruitabscissiondramaticallyreduced.

• The combined MOP and Polysulphate applications significantlyreducedmealybuginfestation.

• PlantssuppliedwithcombinedMOPandPolysulphateshowedincreasedlevelsofleafK,S,Ca,andMgascomparedwiththeunfertilizedcontrol.

• Combined MOP and Polysulphate applied at the doubled dose (240 kg K2O/ha) gave rise to the best crop performance andtothehighestyield,producequality,andprofit.

KCl/Polysulphate dose (kg K2O/ha)

Pepp

er y

ield

(t/h

a)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0 2016 2017

FP,270/0 120/0 60/60 120/120 180/180Control,0/0From research funded by the International PotashInstitutewww.ipipotash.org.

+147%yield increase

in 2016

+128%yield increase

in 2016

WhenJanuary2016December 2017Garden planted in 2012

WhereGiaLaiprovince,CentralHighlands,Vietnam

CropBlack pepper (Piper nigrum L.)

Soil typeAcidic reddishbrownsoil

Measurements• Yield and quality• Vegetativegrowth• Diagnostic leaves• Mealybugs

infestation

Black pepperVietnam

5


®

Trial

BroccoliFrance

ObjectiveToinvestigatetheeffectoftheapplicationofsingleandsplitapplications of Polysulphate on the yield of broccoli.

TreatmentsThisfieldtrialconsistedofthreetreatmentsinfourreplicates:• Farmer’sfertilizerpractice(control)• Polysulphate applied 15 days after planting at a rate of 150 kg/ha.• Polysulphate applied 15 and 40 days after planting (split

application)atarateof150kg/haeach(total300kg/ha).M

g co

nten

t in

head

s (m

g/kg

)

170

171

172

173

174

175

Control Polysulphate2x150 kg/ha

K co

nten

t in

head

s (m

g/kg

)

3,6503,7003,7503,8003,850

3,9003,9504,000

Polysulphate2x150 kg/ha

Control

Yiel

d(t/

ha)


12.012.513.013.514.014.515.015.5

Control

Ca c

onte

nt in

hea

ds

(mg/

kg)

300

350

400

450

500


Control

+13%yield

increase

Results• The split Polysulphate application (2 x 150 kg/ha) resulted in the best response. The single application had no effectonthecrop.• The yield of the split Polysulphate treatment improved by

13%overthecontrol,thismeans1.75mt/hayieldincreasebasedon25,000plants/ha.

• Theaverageheadsizeincreasedfrom534ginthecontrolto604gwiththetwoPolysulphateapplications.

• Potassium,magnesiumandcalciumcontentintheheadswiththesplitPolysulphateapplicationincreasedby5%,1.7%and23%respectivelycomparedtothecontrol.

When2016

WhereFrance,Kervignac

CropBroccoli (Brassica oleracea var. italica)

Soil typeSandy loam soil

Measurements• Yield• Nutrients content

in the head

6

®

Trial

CabbageBrazil Objective

EvaluatetheyieldandqualityofthecabbagewhenKClissubstitutedwithPolysulphateasthesourceofpotassium.

TreatmentsThisrandomizedblocktrialconsistedoffourreplicateswithseven differenttreatments.Withtheexceptionofthecontrol,thetreatmentsconsistedofdifferentcombinationofKClandPolysulphatewiththetotalK2O application rate remaining at 200kg/ha.Eachtreatmentwasapplied(broadcast)tothesoilsurface in 4 equal applications the day before planting and at 14,28and42daysafterplanting.

Atplanting,alltreatmentswerefertilizedwith400kg/haofP2O5 (MAP),broadcastandincorporatedintothesoil,and200 kg/ha of N (urea) applied at the same time as the initial treatment applications.

Results• Polysulphate increased vigor and reduced the risk of black rot. • Partial replacement of KCl by Polysulphate increased crop productivity.• Theratiosbetween40and80%Polysulphateintheblend

withKClarethemostindicated,eveninhighfertilitysoils.

Different letters within columns indicate statistically significant differences

Vigo

r

6

8.0

7.0

7.5

6.5 bab

ab ab aba a

100% KCI 60% KCI+40%

Polysulphate

40% KCI+60%

Polysulphate

100% Polysulphate

20% KCI+80%

Polysulphate

80% KCI+20%

Polysulphate

Zero K2O

Yiel

d (t/

ha)

150

160

140

130

cbc

ab ab

a

abcabc

100% KCI 60% KCI+40%

Polysulphate

40% KCI+60%

Polysulphate

100% Polysulphate

20% KCI+80%

Polysulphate

80% KCI+20%

Polysulphate

Zero K2O

+13%increase in

relation KCl

When• Sowing: October 2016 • Harvest: January2017

WherePiedade,SaoPaulostate,Brazil

CropCabbage (Brassica oleracea)

Soil typeClay soil

Measurements• Yield• Incidence of black

rot in the leaves (Xanthomonas campestris)

• Plant vigor

7

®

Trial

Winter cabbageUK

ObjectiveToinvestigatetheeffectofPolysulphateapplicationontheyieldofwintercabbage,withparticularemphasisonresponseto the sulphur content.

Treatments• Thefieldtrialconsistedoffivereplicates.• Thewholefield,includingthetrialsite,receivedthe

standardNPKdressingusedbythegrower.Nosulphurwasapplied.

• FourratesofPolysulphatewerespreadasatop-dressingtosupplysulphurat30,60,90and120kgSO3/ha(12,24,36and 48 kg S/ha).

• ThecontrolplotsandthethreelowerS-rateplotsreceiveda dressing of calcined magnesite and muriate of potash (KCl) to match the quantities of magnesium and potassium provided by the highest Polysulphate application rate. The trialsitewasadequatelysuppliedwithcalcium.

50

0Control Polysulphate

150

100

Yiel

d (t/

ha)

+40%yield

increase

When2009

WhereLincolnshire,UKandcarried out byOAT (Oxford Agricul-ture Trials Ltd)

CropWinter cabbage (Brassica oleracea)


Measurements• Vigour• Yield

Results• TheaveragevigourscoreforthePolysulphateplotswas90%

ormorethroughoutthewinter,whereasthecontrolplotvigourhaddeclinedto74%bymid-autumn,subsequentlyremaining at that level.

• AllthePolysulphatetreatmentsshowedasignificantyieldimprovement over the control. The average yield of the Polysulphatetreatmentswas40%greaterthanthecontrol.

• Theoptimumsulphurapplicationratewas90kgSO3/ha (36kgS/ha).ThisratewasachievedwhenPolysulphatewasapplied at 190 kg/ha.

8

®

Trial

Chinese cabbageChina

ObjectiveToinvestigatetheeffectofincreasingratesofPolysulphateontheyield,growthparameters,concentrationsofsoilnutrientsandsoilpHafterharvestof Chinese cabbage.

TreatmentsThisrandomizedblocktrialconsistedoffourreplicateswithfivetreatments.Inalltreatments,nitrogen,phosphorusandpotassiumwereappliedaccordingtofarmers’traditionalpractice:450kg/haofcompoundfertilizer(15-15-15)+7.5t/haoforganicfertilizerappliedasbase-fertilizer.FourtreatmentsconsistedofincreasingratesofPolysulphate:375,750,1,125and1,500kg/ha.ControltreatmentreceivedthesameNPKandorganicfertilizer+300kg/hacalciumcyanamidebutnoPolysulphatewasapplied.

Results• Potassium,MgandCaconcentrationsinsoilafterharvestwere

increasedinthePolysulphatetreatmentswhencomparedtothecontrol.• Polysulphate application increased soil pH after harvest from 4.9

(control)upto5.28(1,500kgPolysulphate/ha).• ApplicationofPolysulphateincreasedsignificantlythestemdiameter

androotweightofChinesecabbage.• Polysulphateapplicationincreasedsignificantlytheyield.Thehighest

yieldswereobtainedwhenPolysulphatewasappliedatarateof375and 750 kg/ha.

• Polysulphateapplicationwashighlyprofitable.Thehighestadditionalnetprofit(2,978USD/ha)wasobtainedwhenPolysulphatewasappliedatarateof375kg/ha.

Polysulphate (kg/ha)

Soil pH

Available K (mg/kg)

Exchangeable Mg (mg/kg)

Exchangeable Ca (mg/kg)

0 4.88 124.4 90.2 772.6

375 4.99 145.0 126.9 1,142.6

750 5.06 218.2 132.4 1,886.6

1,125 5.03 199.0 180.3 1,063.1

1,500 5.28 286.4 208.5 2,138.3

Polysulphate rate (kg/ha)

Yiel

d (t/

ha)

20

21.5

22.5

23.75

25

0 375 750 1,125 1,500

b

a a

ab ab

Stem

dia

met

er (m

m)

Rootweigh

t(g/10

plants)

15

17

19

21

23

Polysulphate rate (kg/ha)0 375 750 1,125 1,500

stem diameterrootweight

b

c

ab

bc

a

a

a

ab

a

ab

Different letters above bars indicate significant differences among treatments (p<0.05)

+18%yield

increase

When• Sowing: July14,2015• Harvest: August14,2015

WhereHainan,China

CropChinese cabbage (Brassica rapa pekinensis)

Soil typePaddy soil

Measurements• Yield• Growth

parameters• Soil nutrients after

harvest• Soil pH after

harvest

9

®

Trial

CabbageTurkey

ObjectiveToinvestigatetheeffectofPolysulphate,potassiumsulphate(SOP)andpotassiumchloride(MOP,KCl)ontheyield,qualityparameters and nutrient uptake of cabbage.

TreatmentsThisrandomizedtrialconsistedoffourreplicateswithfivetreatments.Nitrogen,phosphorusandpotassiumwereappliedaccording to target yield and soil tests at a rate of 250 kgN ha-1(asureaanddiammoniumphosphate,DAP),100kgP2O5 ha-1(asdiammoniumphosphate,DAP)and300kgK2O ha-1 (asPolysulphate,SOPorMOP).Anadditionaltreatmentconsistedin K given 50% from SOP and 50% from Polysulphate. Control treatmentreceivedthesameNandPdosesbutnoKwasapplied.

Results• UptakeofCa,MgandSwerehighestinthePolysulphate

treatment.AlsoCa,MgandSconcentrationsintheleaveswerehighestinthePolysulphatetreatment.

• Polysulphate+SOPtreatmentresultedinthehighesttotalandmarketableyield,followedbythePolysulphatetreatment.Alsoheadweight,widthandheightfollowedthesamebehavior.

• Polysulphateapplicationincreasedthenetreturnandwasveryprofitable,withaB:C(benefit:costratio)of20.3forPolysulphatetreatmentand28.3forthePolysulphate+SOPtreatment.

• Thehighestantioxidantactivity,phenolsconcentrationandtotalsolublesolids(TSS)werefoundinthePolysulphate+SOPtreatment,followedbythePolysulphatetreatmentwhichstatisticallydidnotdifferfromthePolysulphate+SOPtreatment.VitaminCconcentrationwasfoundhighestatthePolysulphate treatment.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Mg,and

Caup

take-%

MgSCa

bc

c

b

bc

bc

c

b

c

c

ab

b

b

a

a

a

Control MOP SOP SOP+Polysulphate Polysulphate

Different letters above bars indicate significant differences among treatments (p<0.001).


40

50

60

70

80

90

100

110


cbc

a

ab

Yiel

d - t

/ha

d

+45%yield

increase

WhenSowing:September 2016 Harvest:January2017

WhereAntalya,Turkey

CropCabbage (Brassica oleracea)


Measurements• Yield• Quality

parameters• Nutrients uptake

10


®

Trial

CabbageIndia

ObjectiveTotesttheefficacyofPolysulphateasasulphursourceontheperformance of cabbage crop in India.

TreatmentsTheexperimentwaslaidoutinarandomizedblockdesignwiththreereplicates and included six treatments:• T1: ControlwithoutSandKfertilization (100%NPonlythroughurea,DAP)• T2: 100%NPK(urea,DAP,MuriateofPotash(MOP))• T3: 100%NP+50%SthroughPolysulphate(10kgSha-1) (balanced K through MOP to make 100% K)• T4: 100%NP+75%SthroughPolysulphate(15kgSha-1) (balanced K through MOP to make 100% K)• T5: 100%NP+100%SthroughPolysulphate(20kgSha-1) (balanced K through MOP to make 100% K)• T6: 100%NPK(urea,DAP,MOP)+100%Sthroughgypsum (20 kg S ha-1)

The recommended dose of fertilizers:150kgN,100kgP2O5 ,125kg K2O ha–1 and 20 kg S ha–1wasappliedasperthetreatments.Farmyardmanure(FYM)wasalsoappliedat25tha-1 in the last plough.

Results• Sapplicationsignificantlycontributedtoincreasedyieldandquality

(head diameter and compactness at harvest) of cabbage. • SapplicationintheformofPolysulphate,upto75%ofthe

recommendedSdose(T4),enhancedplantgrowthanddevelopment,improvingplantheightandnumberofleaves.

• HighestascorbicacidcontentandTSSwereobtainedwithSapplicationasPolysulphate,75%oftherecommendedSdose(T4).

• N,K,Ca,andSuptakebycabbagecropwashighestwhenSwasappliedintheformofPolysulphate,upto75%oftherecommended S dose (T4).

• ThehighestyieldwasobtainedwithafulldoseN-P-Kand75%SdosedeliveredthroughPolysulphate(T4),whichgaveriseto32.8%increaseintheyieldofcabbage,comparedtothenon-fertilized control (T1).

Bars indicate LSD at P<0.05.


Yiel

d (t/

ha)

25

30

35

15

10

40

45

50

Treatments

T1NP

T2NPK

T3NPKS10

Polysulphate

T4NPKS15

Polysulphate

T5NPKS20

Polysulphate

T6NPKS20

Gypsum

+32.8%increase

(comparedto T1)

WhenSowing:October2013Harvest: March 2014

WhereHessaraghatta,Karnataka,India

CropCabbage (Brassica oleracea var. capitata) cv. Tetries

Soil typeSandy clay loam (Typic haplustepts)

Measurements• Yield • Quality• Growth

parameters• Nutrient uptake

11


®

Trial

CarrotFrance

ObjectiveTocomparethreedifferentsourcesofpotassium(MOP,SOPandstandardPolysulphate)ontheyieldofcarrotsgrowninthenorth–westofFrance.

TreatmentsThetrialconsistedofmicroplotswith4replicates.Thetreatments had the same potassium dose (250 kg K2O/ha) givenaseitherMOP,SOPorstandardPolysulphate.

Nitrogenwasappliedasperfarmers’practiceatarateof84kgN/ha(as250kgofammoniumnitrate).NophosphoruswasappliedbecausesoilanalysisshowedahighsoilPcontent.

ResultsPolysulphate application increased carrot yield by in all cases: by24%comparedwiththecontrol(noKapplication);by12.5%comparedtoMOP;andby3%comparedtoSOP.


Pota

to y

ield

(t/h

a) 70

65

60

75

50

55

Control0 kg K2O/ha

Potassium chloride

250 kg K2O/ha

Potassium sulphate

250 kg K2O/ha

Standard Polysulphate

250 kg K2O/ha

+24%yield

increase

WhenSowing:April2019Harvest:July2019

WhereSaint-Jean-Brévelay,Brittany,France

CropCarrot (Daucus carota cv. Salto)

Soil typeLoamysoil,pH6

MeasurementsYield

12


®

Trial

CauliflowerIndia

ObjectiveTotesttheefficacyofPolysulphateasasulphursourceontheperformanceofcauliflowercropinIndia.

TreatmentsTheexperimentwaslaidoutinarandomizedblockdesignwiththreereplicates and included six treatments:• T1: ControlwithoutSandKfertilization (100% NP through urea and DAP only) • T2: 100%NPK(urea,DAP,MuriateofPotash(MOP))• T3: 100%NP+50%SthroughPolysulphate(10kgSha-1) (balanced K through MOP to make 100% K)• T4: 100%NP+75%SthroughPolysulphate(15kgSha-1) (balanced K through MOP to make 100% K)• T5: 100%NP+100%SthroughPolysulphate(20kgSha-1) (balanced K through MOP to make 100% K)• T6: 100%NPK(urea,DAP,MOP)+100%Sthroughgypsum

(20 kg S ha-1)

The recommended dose of fertilizers:150kgN,100kgP2O5,125kgK2O ha–1 and 20 kg S ha–1wasappliedasperthetreatments.Farmyardmanure(FYM)wasalsoappliedat25tha-1 in the last plough.

Results• Sapplicationsignificantlycontributedtoincreasedyieldand

quality(curddiameterandcompactnessatharvest)ofcauliflower.• SapplicationintheformofPolysulphate,upto75%ofthe

recommendedSdose(T4),enhancedplantgrowthanddevelopment,improvingplantheightandnumberofleaves.

• N,K,Ca,andSuptakebycauliflowercropwashighestwhenSwasappliedintheformofPolysulphate,upto75%oftherecommended S dose (T4).

• ThehighestyieldwasobtainedwithafulldoseN-P-Kand75%SdosedeliveredthroughPolysulphate(T4),whichgaveriseto39.5%increaseintheyieldofcauliflower,comparedtothenon-fertilized control (T1).

Bars indicate LSD at P<0.05.

From research funded by the International Potash Institute www.ipipotash.org. Treatments

Yiel

d (t/

ha)

20

25

15

10

30

T1NP

T2NPK

T3NPKS10

Polysulphate

T4NPKS15

Polysulphate

T5NPKS20

Polysulphate

T6NPKS20

Gypsum

+39.5%increase

(comparedto T1)

WhenSowing:October2013Harvest: March 2014

WhereHessaraghatta,Karnataka,India

CropCauliflower (Brassica oleracea var. botrytis) cv. Unathi

Soil typeSandy clay loam (Typic haplustepts)

Measurements• Yield • Quality• Growth

parameters• Nutrient uptake

13


®

Trial

CoffeeVietnam

WhenFirst application: April 2015Harvested: December 2015

WhereDiLinhdistrict,LamDongProvince,Vietnam

CropCoffee(Coffea robusta)

Soil typeGrey soil

Measurements• Yield• Fruitweight• A-size core

ObjectiveToevaluatetheefficacyofPolysulphatetoincreasecoffeeyieldinVietnam,andtoevaluatethecost-effectivenessofapplyingfertilizers in split doses compared to the traditional practice of asingleapplicationofurea,KCl,andfusedCa,Mg,andP.

TreatmentsThis completely randomized block trial comprised three replications,eachwiththreetreatments:1) Traditionalpractice/control:singleapplicationofurea,KCl,and

fusedCa,Mg,andP.2)Commerciallyavailablecompoundfertilizers(withSbutno

Ca or Mg).3)Sameas(2)butsupplementedwithPolysulphate.

Inthetwotreatments,thetotalfertilizerdosewassplitintofourapplications,oneatthebeginningofthedryseasonandtheremainingthreeinearly,mid,andlaterainyseason.

Treatment Urea Fused Ca Mg P

KCl NPKS 16-16-8-13

NPK 15-15-15

NPKS 15-18-20-10

Polysulphate

Control 715 1193 545 - - - -Compound fertilizers+S

250 - 200 400 500 500 -

Compound fertilizers +SwithPolysulphate

250 - 153 400 500 500 200

Application rate: kg/ha

Results• SupplementingNPKwithPolysulphateresultedinanincrease

in yield of 9% and superior quality produce – more than 22% of thecoreswereofsizeA,orlargerthan6.3mmindiameter.

• Higheryieldwasduetofastergrowth,longerfruitingbranches,lesssheddingofimmaturefruit,andlargerandheaviercores.

•Polysulphateapplicationalsoincreasednetprofitsby10%.

Bars indicate LSD at 5%.

Source: Petrovietnam Fertilizer and Chemicals Corporation

Fruitweight

90

91

92

93

94

95

96

g/10

0 fr

uit

Yield

0.00.51.01.52.02.53.03.54.04.5

t/ha

A-size core

15161718192021222324

Perc

ent

Compoundfertilizers+S

Compoundfertilizers+SwithPolysulphate

Control

+9%yield

increase

14

®

Trial

CoffeeVietnam

ObjectiveToevaluatetheefficacyofPolysulphatetoincreasecoffeeyieldinVietnam,andtoevaluatethecost-effectivenessofapplyingfertilizers in split doses compared to the traditional practice of asingleapplicationofurea,KCl,andfusedCa,Mg,andP.

TreatmentsThis completely randomized block trial comprised three replications,eachwiththreetreatments:1) Traditionalpractice/control:singleapplicationofurea,KCl,and

fusedCa,Mg,andP.2) Commercially available compound fertilizers (withSbutnoCaorMg).3)Sameas(2)butsupplementedwithPolysulphate.

Inthetwotreatments,thetotalfertilizerdosewassplitintofourapplications,oneatthebeginningofthedryseasonandtheremainingthreeinearly,mid,andlaterainyseason.

Treatment Urea Fused Ca Mg P

KCl NPKS 16-16-8-

13

NPK 15-15-15

NPKS 15-18-20-10

Polysulphate

Control 715 1193 545 - - - -Compound fertilizers+S

250 - 200 400 500 500 -

Compound fertilizers +SwithPolysulphate

250 - 153 400 500 500 200

Application rate: kg/ha

Results• SupplementingNPKwithPolysulphateresultedinanincrease

in yield of 11.5% and superior quality produce – more than 22% ofthecoreswereofsizeA,orlargerthan6.3mmindiameter.

• Higheryieldwasduetofastergrowth,longerfruitingbranches,lesssheddingofimmaturefruit,andlargerandheaviercores.

•Polysulphateapplicationalsoincreasednetprofitsby14%.

Bars indicate LSD at 5%.

Source: Petrovietnam Fertilizer and Chemicals Corporation

Fruitweight

90

91

92

93

94

95

96

g/10

0 fr

uit

Yield

0.00.51.01.52.02.53.03.54.04.5

t/ha

A-size core

15161718192021222324

Perc

ent

Compoundfertilizers+S

Compoundfertilizers+SwithPolysulphate

Control

WhenFirst application: April 2015Harvested: December 2015

WhereBaoLamdistrict,LamDongProvince,Vietnam

CropCoffee(Coffea robusta)

Soil typeReddishbrownsoil

Measurements• Yield• Fruitweight• A-size core

+11.5%yield

increase

15

®

Trial

CottonTurkey

ObjectiveToinvestigatetheeffectofPolysulphate,potassiumsulphate(SOP)andpotassiumchloride(MOP,KCl)ontheyieldandquality parameters of cotton.

TreatmentsThisrandomizedtrialconsistedoffourreplicateswithfourtreatments.Nitrogen,phosphorusandpotassiumwereappliedaccording to target yield and soil tests at a rate of 250 kg N ha-1

(asammoniumnitrateanddiammoniumphosphate,DAP),184 kg P2O5 ha-1(asdiammoniumphosphate,DAP)and210kg K2O ha-1(asPolysulphate,SOPorMOP).ControltreatmentreceivedthesameNandPdosesbutnoKwasapplied.

Results• Seedcottonyieldwassignificantlyincreasedbyall3K

sources.TheyieldofthePolysulphatetreatmentswas77%greaterthanthecontrolwithoutKapplication.YieldsofPolysulphateandSOPtreatmentsweresignificantlythesame.

• Polysulphateapplicationincreasedthenetreturnandwasveryprofitable,withaB:C(benefit:costratio)of9.2.

• ThehighestfiberelongationwasfoundinthePolysulphatetreated cottons. This is one of the most important physical parameters for cotton quality.

5.4

5.6

5.8

6.0

6.2

6.4

6.6

Control

c

MOP

b

Polysulphate

a

Fibe

r elo

ngat

ion

- %

SOP

bc



WhenSowing:May2016Harvest:October 2016

WhereAntalya,Turkey

CropCotton (Gossypium hirsutum)


Measurements• Yield• Fiber elongation

+12.5%increase

16


®

Trial

Mixed pastureThe Netherlands

ObjectiveToevaluatetheeffectofPolysulphateontheyieldandqualityofamixedpasture(grassandclover)inanorganicfieldintheNetherlands.

TreatmentsThetrialconsistedoftwostripsofgrasspasture.Each20x100meter strip received 25 t/ha of cattle slurry in the 1stcut,and10 t/ha in the 2ndcut.Onestripwasalsotreatedwith100kg/haof granular Polysulphate in the 1st cut.

Thegrassandcloverfrom4differentrectanglesineachstripwereweighedandanalyzed.These3x2meterrectangleswere20 meters apart.

Results• Polysulphate application increased the dry matter

production by 9.6%.• Nutritionalvaluesoftheforageincludingfeedunitmilk,

intestine digestible protein and sugar content also improved withPolysulphateapplication.

• AdditionalincomeduetoPolysulphateapplicationwas€273/ha(basedonapriceof€0.17/kgVEMand€0.65/kgDVE).

Yield 1st + 2nd cuts9000

8000

7000

6000

5000

4000

3000

2000

1000

0Dry matter

kg/haVEM

kg/haDVE

kg/haCrude protein

kg/haSugarkg/ha

Income(€/ha)

0 kg/ha Polysulphate


+9.6%DM yieldincrease

WhenSowing:2016Harvested: 2019(1st and 2nd cuts)

WhereHeerenveen,theNetherlands

CropMixed pasture (red andwhitecloverandryegrass) (Trifolium repens, Trifolium pratense and Lolium perenne)

Soil typeSandy

Measurements• Dry matter yield • Feed unit milk

(VEM)• Intestine digestible

protein (DVE)• Crude protein• Sugar content

17

®

Trial


ObjectiveToevaluatetheeffectofPolysulphateontheyieldandqualityofamixedpasture(grassandclover)grownonsandysoilin the Netherlands.

TreatmentsThetrialconsistedoftwostripsofgrasspasture.Each20x100meterstripreceived22t/haofcattleslurryeachcut,24kgN/ha and 15 KG SO3/hainthefirstcutand27kgN/haandin2ndcut.Onestripwasalsotreatedwith100kg/haofgranularPolysulphate in the 1st cut.




intestinedigestibleprotein,crudeproteinandsugarcontentalsoimprovedwithPolysulphateapplication.

• AdditionalincomeduetoPolysulphateapplicationwas€68/ha(basedonapriceof€0.17/kgVEMand€0.65/kgDVE).

Dry Matter kg/ha

VEMkg/ha

DVEkg/ha

Crude proteinkg/ha

Sugarkg/ha

Income(€/ha)

Yield 1st + 2nd cuts6000

5000

4000

3000

2000

1000

0





WhereGorredijk,theNetherlands


Soil typeSandy




18

®

Trial

Mixed grassThe Netherlands


WhereHantumhuizen,theNetherlands

CropMixed grass (perennial and cross-bredryegrass,tall fescue and Festulolium)(Lolium perenne, Festuca arundinacea and Festulolium sp.)

Soil typeClay




ObjectiveToevaluatetheeffectofPolysulphateontheyieldandqualityofagrasspasturegrownonclaysoilintheNetherlands.

TreatmentsThetrialconsistedoftwostripsofgrasspasture.Each20x100meterstripreceived35t/haofcattleslurryinthe1stcut,and81 kg N/ha in the 1st and 2ndcut.Onestripwasalsotreatedwith300kg/haofgranularPolysulphateinthe1st cut.

Thegrassfrom4differentrectanglesineachstripwasweighedandanalyzed.These3x2meterrectangleswere20metersapart.




• Polysulphateapplicationincreasedincomeby€195/ha (basedonapriceof€0.17/kgVEMand€0.65/kgDVE).

Dry matter kg/ha

VEMkg/ha

DVEkg/ha

Crude proteinkg/ha

Sugarkg/ha

Income(€/ha)

Yield 1st + 2nd cuts

9000

8000

7000

6000

5000

4000

3000

2000

1000

0


300kg/haPolysulphate


19

®

Trial



WhereGersloot,theNetherlands


Soil typePeat




ObjectiveToevaluatetheeffectofPolysulphateontheyieldandqualityofamixedpasture(grassandclover)grownonapeatsoilin the Netherlands.

TreatmentsThetrialconsistedoftwostripsofgrasspasture.Each20x100meter strip received 46 kg N/ha in the 1st and 2nd cut. One strip wasalsotreatedwith100kg/haofgranularPolysulphateinthe1st cut.


Dry matter kg/ha

VEMkg/ha

DVEkg/ha

Crude proteinkg/ha

sugarkg/ha

Income(€/ha)

Yield 1st + 2nd cuts

8000

7000

6000

5000

4000

3000

2000

1000

0







• AdditionalincomeduetoPolysulphateapplicationwas €156/ha(basedonapriceof€0.17/kgVEMand €0.65/kgDVE).

20

®

Trial

Green pepperChina

ObjectiveToinvestigatetheeffectofincreasingratesofPolysulphateonthesoilpHafterharvest,yieldandshelflifeofgreenpepper.

TreatmentsThisrandomizedblocktrialconsistedofthreereplicateswithfivetreatments.Inalltreatments,nitrogen,phosphorusandpotassiumwereappliedaccordingtofarmers’traditionalpractice:1,125kg/haofcompoundfertilizer(15-15-15)appliedasbase-fertilizerfollowedbyatopdressingof375kg/haofcompoundfertilizeratfruitstage.FourtreatmentsconsistedofincreasingratesofPolysulphate:375,750,1,125and1,500kg/ha.ControltreatmentreceivedthesameNPKbutnoPolysulphatewasapplied.

Results• Application of Polysulphate increased the pH after harvest and thus the

availabilityofnutrientsinthesoil,especiallyforK,CaandMg,thatinturn improves the fertility of acidic soil.

• Therewasnosignificantdifferenceinthepercentageofmarketablepepper among all treatments after 9 days of storage. As the storage timewasincreasedfrom9daysto15andthen20days,asignificantlyhigherpercentageofmarketablepepperwasachievedintreatmentsthatcontainedPolysulphate,duetoimprovedshelflife.

• ComparingPolysulphatetreatmentswiththecontrol,theyieldsofgreenpepperincreasedsignificantlybyupto24%atthehighestdose

(1,500kgPolysulphate/ha).• Polysulphateapplicationwasveryprofitable,withincreasingadditional

profitsof960,1,620,2,415and2,250USD/hafor375,750,1,125and1,500kgPolysulphate/harespectivelywhencomparedwiththe

control treatment.

% o

f mar

keta

ble

pepp

er

20 days of storage

a bb b b

15 days of storage

a a b b b

9 daysof storage

a a a a a

20406080

100120

0

0 375 750 1,125 1,500

Polysulphate dose (kg/ha)

Yiel

d co

mpa

red

to

cont

rol (

%)


0.0

32.5

65.0

97.5

130.0

0

c

375

bc

750

ab

1,125

a

1,500

a

Soil

pHaf

ter h

arve

st

4.54.74.95.15.35.5

0 375 750 1,125 1,500

Different letters above bars indicate signifi-cant differences among treatments (p<0.05)

+24%yield

increase

WhenTransplant: December7,2015Harvest:January2-April16,2016

WhereHainan,China

CropGreen pepper (Capsicum annuum)


Measurements• Yield• Shelf life• Soil pH after

harvest

21

®

Trial

LucerneUK

ObjectiveToinvestigatetheeffectoftheapplicationofPolysulphateonthenutritionalqualityoflucerne(alfalfa).SpecificallytoincreasetheSlevelandimprove(tighten)theN:Sratiowiththeobjectiveofincreasing crude protein and improving digestibility.

Treatments• Thiswasasplitfieldtrial.• A standard broadcast spring application of a phosphate/

potash(PK)fertilizerwascomparedwithatreatmentprovidingthesamePKinputs,plussulphate,magnesiumand calcium from Polysulphate.

• Theratesofapplicationofthenutrientsappliedareshownin the table (kg/ha):

N P2O5 K2O MgO SO3 CaO

Standard PK 0 80 120 - - -

PK+Polysulphate 0 80 120 12 96 34

20.0

18.0

17.0

19.0

N:S ratio in lucerne Crude protein in lucerne

Crud

e pr

otei

n - %

16.0

15.0with

Polysulphatewithout

Polysulphate

25.0

15.0

10.0

20.0

N:S

ratio

5.0

0with

Polysulphatewithout

Polysulphate

Results• TheN:Sratioof20:1withthestandardPKfertilizerwas

narrowedtothedesired12:1bythePolysulphatetreatment.AnN:Sratioof20:1isconsideredtoowideforoptimaldigestibility of the fodder and for maximum nitrogen use efficiencybyruminantlivestock.

• The nitrogen content of the fodder (measured as ‘crude protein’)wasimprovedbythePolysulphatetreatment,indicating that an adequate sulphur supply is necessary to enablethiscroptofixandutilisenitrogenefficiently.

When2017

WhereUK

CropLucerne(alfalfa,Medicago sativa)

Soil typeSandy clay loam

Measurements• N:S ratio• Crude protein• Digestibility

+9.7%protein increase

22

®

Trial

MaizeArgentina

When2016

WhereNuevedeJulio,Argentina

CropMaize (Zea mays)


MeasurementsYield

ObjectiveTocompare,underfieldconditions,theagronomicandeconomicefficiencyoffertilizerbulkblendsthatincludePolysulphatewithothercurrentformulations.

Different letters above bars indicate signifi-cant differences among treatments (p<0.001)


Mai

ze y

ield

- kg

/ha

Control (S=0)

SSP (S=19)

MAP+Gypsum (S=19)

MAP+Polysulphate 63%(S=19)


MAP+Polysulphate 84% (S=57)

a

b b b b b15,000

17,500

10,000

12,500

7,500

5,000

TreatmentsThetreatmentswereallocatedinarandomizedcompleteblockdesignwithfourreplications.

AlltreatmentswerebasedondifferentsourcesofSthatwereappliedatsowingandwithasinglerateofP(30kgP2O5 ha–1),inadditiontootherfertilizercombinations,includingacontrolwithnosulphur.Gypsumandsinglesuperphosphate(SSP)treatmentswereincluded,sincetheywerethecommonsourcesofSwithcomparableratesofStoPolysulphate.

ThecropreceivedabroadcastfertilizationwithNasureaatV4-V6stageinadditiontotheNappliedthroughtheMAPstarter,thus providing 100 kg N ha–1.

Results• Maizerespondedsignificantlytosulphurapplication• TherewerenostatisticaldifferencesbetweenPolysulphate

and other sources of sulphur.

+14.9%yield increase


23


®

Trial

MaizeArgentina

When2017

WhereMercedes,Corrientes,Argentina

CropMaize (Zea mays)


MeasurementsYield




ThecropreceivedabroadcastfertilizationwithNasureaatV4-V6stageinadditiontotheNappliedthroughtheMAPstarter,thus providing 100 kg N ha–1.

Mai

ze y

ield

- kg

/ha

cbc

a a aab

10000

5000

7500

2500

0Different letters above bars indicate signifi-cant differences among treatments (p<0.05)


Control (S=0)

SSP (S=19)

MAP+Gypsum (S=19)




ResultsTherewerenostatisticaldifferencesbetweenPolysulphateandgypsum.PolysulphategavehigheryieldascomparedwithSSP.

+31%yield increase


24


®

Trial

Silage maizeUK

WhenSowing:May2017Harvest:October 2017

WhereDorset,UKand carried out by Pearce Seeds

CropSilage maize(Zea mays)

MeasurementsDry matter yield

54

52

51Control +Polysulphate

55

53

DAP

CWD

- %

Silage metabolisable energy Cell wall digestibility

11.25

10.75

10.50

11.00

ME-M

J/kg

Control +PolysulphateDAP

ObjectiveToinvestigatetheeffectofdi-ammoniumphosphate(DAP)orDAPwithPolysulphateplusmicronutrientsontheearlyvigourand quality of maize silage.

TreatmentsThisrandomisedtrialconsistedoffourreplicateswiththreetreatments.TheDAPandtheDAP/Polysulphateblendwereapplied at drilling to provide the same application rate of nitrogenperhectare,withthecontrolreceivingnofertiliser.

Thetreatmentfertiliserswerebandedwiththeseedatdrillingon 10 May 2017. All treatments also received additional nitrogen,withtotalNapplicationsbeingequal.

Results• Thefirstassessmentofcropvigourshowedapositiveeffect

from both fertiliser treatments.• Themetabolisableenergyoftheharvestedcropwas

significantlyhigherfromthePolysulphate-treatedcropthanthe DAP treatment or the control.

• ThecellwalldigestibilityofthePolysulphatetreatedcropwassignificantlygreaterthaneithertheDAPtreatmentorthe control.

• ThePolysulphateareawasworthanextra£82.50/ha or£77.40/haafterdeductingthecostsofPolysulphate.

15.8

15.4

15.0

14.8

16.4

16.0

15.6

15.2

Control DAP Polysulphate

16.2

16.8

16.6

15.48

16.05

16.6

Dry

mat

ter –

t/ha

Maize dry matter yield+7%

yieldincrease

25

®

Trial

MaizeUK

ObjectivesToinvestigatetheeffectoftheapplicationofPolysulphateandDAPontheproductionofgasfrommaizegrownforbiogas.

TreatmentsThetrialconsistedoftwofertilizer treatments for biogas maize. The control treatmentfollowedstandardpractice,applying125kg/ha of DAP. In the second treatment,Polysulphatewasapplied at 67 kg/ha and DAP at 125 kg/ha.

Results• SPADchlorophyllmeterreadingsshowedasignificant

increaseinchlorophyllcontentwhenfertilizedwithPolysulphate.

• Polysulphate improved dry matter by 7.1% over the control.• Theoverallyield,measuredbytheharvestingrigs,increased

by1.6t/hainthePolysulphatefertilizedarea,giving5.6%moreyieldascomparedwiththefarmers’practice.

60

50

40

30

20

10

0

Quality parameters of maize

Dry matter % Starch % Metabolisable energy(MJ/kgDM)

Crude protein %

52.0

50.0

48.0

46.0

44.0

42.0

40.0

38.0

Chlorophyll content

Farmers’practice(DAP) Farmers’practice+Polysulphate

Farmers' practice (DAP)

Farmers'practice+Polysulphate

Bars indicate average and standard errors

SPAD

read

ing

When2018

WhereLincolnshire,UK

CropMaize (Zea mays cv. Beethoven)

Soil typeMedium loam

Measurements• SPAD• Yield• Quality

DAP 125 kg/ha

Polysulphate 67 kg/ha

and DAP 125 kg/ha

Field layout

+17.8%dry matter

increase

26

®

Trial

MaizeMexico

ObjectiveToevaluatetheeffectonmaizeyieldandgrainqualityofusingPolysulphateasacomplementaryKandSsource,partiallysubstituting KCl (MOP) fertilizer.

TreatmentsThisrandomizedblocktrialconsistedoftwentyplotswithfivePolysulphatedoses(0,34,68,136,and272kg/ha)appliedincorporated at planting. All treatments received a total NPK applicationof300,100and50kg/hafromurea,DAPandusingPolysulphate as complementary K source that reduced the KCl application.

Results• Lateplantingintheregionresultedinlowyieldsforall

treatmentsandlowresponsetoPolysulphateintermsofmaize yield (2.2-4.8%).

• ApositiveeffectonproteinandNcontentinmaizegrainwasregisteredatPolysulphateapplicationratesupto272kg/ha.

• Addition of S by Polysulphate improved N and protein contents in the grain from 7 to 19%.

• A recommended Polysulphate application rate of 100-150 kg/ha is suggested for the Guanajuato State region to improve maize productivity and grain quality.

Bars indicate standard errors. Different letters indicate significant differences among treatments by Tukey test (P=0.05)

* From research funded by the International Potash Institute www.ipipotash.org.

Yiel

d (to

n/ha

)

10.0

9.5

9.0

8.5

8.0

7.5

7.0

6.5

6.0

Polysulphate dose (kg/ha)0 34 13668 272

2.2%

Gra

in p

rote

in (%

)

Gra

in N

con

tent

(%)

11.0

10.0

9.0

8.0

7.0

6.0

5.0

1.6

1.5

1.4

1.3

1.2

1.1

1.0

Polysulphate dose (kg/ha)0 34 13668 272

ProteinN

b

ab

a aa

7% 15%19% 17%

WhenPlanting:July2018Harvest:January2019

WhereCelaya,GuanajuatoState,Mexico

CropMaize (Zea mays var. Ocelote)

Soil typeVertisol,claywithneutralpH(7.5),lowOM (1.5%) and high K,Ca,Mg,andNacontent

Measurements• Yield• N and protein

content in grain

+4.8%yield

increase

27


®

Trial

MustardIndia

CD (P=0.05): 0.019 (seed); 0.018 (stover)


Seed

yie

ld (t

/ha)

Treatments

ObjectiveTotesttheefficacyofPolysulphateasasulphursourceontheperformance of mustard crops in India.

TreatmentsTheexperimentwaslaidoutinarandomizedblockdesignwiththreereplicates and included six treatments:• T1: ControlwithoutSandKfertilization (100% NP through urea and DAP only) • T2: 100%NPK(urea,DAP,MuriateofPotash(MOP))• T3: 100%NP+50%SthroughPolysulphate(20kgSha-1) (balanced K through MOP to make 100% K)• T4: 100%NP+75%SthroughPolysulphate(30kgSha-1) (balanced K through MOP to make 100% K)• T5: 100%NP+100%SthroughPolysulphate(40kgSha-1) (balanced K through MOP to make 100% K)• T6: 100%NPK(urea,DAP,MOP)+100%Sthroughgypsum (40 kg S ha-1).

The recommended dose of fertilizers:120kgN,60kgP2O5,60 kg K2O ha–1 and 40 kg S ha–1wasappliedasperthetreatments.FulldoseofP,K,SandhalfdoseofNwereappliedatthetimeofsowingasabasalapplication.TheremaininghalfdoseofNwasappliedintwoequalsplits.

Results• Mustardyieldincreasedsignificantlyandsteadilyinresponseto

theincreasingSdoseappliedthroughPolysulphate(T3-T5).• MustardseedyieldatthemaximumSdose,40kgha–1 applied

withPolysulphate(T5),increasedby35%comparedwithzeroSapplication (T2).

• TheresponseofoilyieldtoPolysulphateapplicationwasdramatic,providing39%increase(T5vs.T2).Sulphurappliedthroughgypsum(T6)alsogaverisetoasignificantincreaseinoilyields,althoughtoalesserextentthanwithPolysulphate.

• Yieldcomponentslikepodsperplant,podlength,seedsperpodandseedweightwerehighestatthemaximumSlevel(T5).

• KandSuptakebymustardcropincreasedwithincreasingSdoseappliedthroughPolysulphate(T3-T5).

5.0

6.0

7.0

8.0

4.0

1.5

2.0

1.0

2.5

3.0

Stov

er y

ield

(t/h

a)

T1NP

T2NPK

T3NPKS20

Polysulphate

T4NPKS30

Polysulphate

T5NPKS40

Polysulphate

T6NPKS40

Gypsum

Seed Stover

+35%increase

(comparedto T2)

WhenSowing:November2013Harvest: March 2014

WhereKanpur,UttarPradesh,India

CropMustard (Brassica juncea)

Soil typeSandy loam

Measurements• Yield • Yield components • Oil content• Nutrient uptake

28


®

Trial

Oilseed rapeUK

ObjectiveInthistrialwelookatautumnandspringapplicationsofsulphatetoWinterOilseedRape(WOSR),primarilylookingatyieldwithdifferenttimingsofsulphur.WeinvestigatesplitapplicationsofS,howthiscanhelpwithestablishmentofthecrop,andwinterhardiness.

TreatmentsWelookedat3differentratesofapplicationofPolysulphateontoWOSR.Thewholefieldhadabasefertiliserof250kg/ha0-20-30.T1,T3andT4(farmpractice)received96kgofSO3 perhainonesingleapplication.T2receivedtwoapplicationsof sulphate to the equivalent of 192 kg of SO3,split96kg/haatplantingand96kg/haearlyspring.Allareasreceived30kgofnitrogen per ha at planting.

T1 T2 T3 T4Polysulphate 200 kg/ha in the autumn (at planting)

Polysulphate 200 kg/ha in the autumn (at planting)

Ammonium sulphate applied to this area

Polysulphate 200 kg/ha in the early spring

Polysulphate 200 kg/ha in the early spring

ResultsThe application of Polysulphate increased the yield in all cases. Autumn and spring application increased the yield by an extra 1.15 t/ha over the farm practice.

ConclusionIntheseresultsPolysulphateincreasedtheyieldbetween 200kg/haand1.15t/ha(T2gavethebestresults).WhenwelookatthereturnafterfertilisercostshavebeendeductedweseethatT1gaveanextra£62.94/ha,T2gaveanextra£291.70/haandT3gaveanextra£21.60/haoverthecontrol.

2.5

1.5

0.5

0.0T2

3.5

3.0

2.0

1.0

Yiel

d - t

/ha

4.0

5.0

4.5

T3T1 T4

+33.6%yield

increase

When2018

WhereUK

CropOilseed rape(Brassica napus)


MeasurementsYield

29

®

Trial

Oilseed rapeChina

ObjectiveToinvestigatetheeffectofincreasingratesofPolysulphateontheyield,yieldcomponentsandnutrientuptakeofwinteroilseedrape.

TreatmentsThisrandomizedblocktrialconsistedoffourreplicateswithsixtreatments.Inalltreatments,nitrogen,phosphorusandboronwereappliedaccordingtofarmers’traditionalpractice:180kgN/ha,75kg P2O5/ha and 1 kg B/ha. Five treatments consisted of increasing ratesofPolysulphate:375,750,1,125,1,500and1,875kg/ha.ThecontroltreatmentreceivedthesameN,PandBapplicationbutnoPolysulphatewasapplied.

Results• Allnutrients(N,P,K,S,CaandMg)uptakeinshootsincreasedin

thePolysulphatetreatmentswhencomparedtothecontrol.ThehighestnutrientuptakewasobtainedwhenPolysulphatewasappliedatarateof1,500kg/ha.

• Allthreeyieldcomponents(podsperplant,seedsperpotand1000-seedweight)increasedsignificantlywithPolysulphateapplication,uptoadoseof1,500kg/ha.

• Polysulphateapplicationincreasedsignificantlytheyield.ThehighestyieldwasobtainedwhenPolysulphatewasappliedatarateof1,500kg/ha.

Polysulphate(kg/ha) N P2O5 K S Mg Ca

Shoot uptake (kg/ha)0 83.1d 7.5 d 100.5 e 29.3e 12.2 e 36.9e375 105.1 c 11.5 c 170.5 d 51.8 d 15.9 d 54.2 d750 115.1 ab 11.9 ab 255.2 c 66.6 bc 18.3bc 66.8 bc1,125 110.6 bc 12.0 bc 286.6 b 72.0 ab 19.1 b 72.3ab1,500 120.0 a 13.0a 320.4a 77.1 a 20.8 a 76.9 a1,875 112.2 abc 12.3abc 298.7 ab 64.6 c 17.3c 64.1 c


Yiel

d (k

g/ha

)

3,100

3,300

3,500

0

d

375

bc

750

bc

1,125

ab

1,500

a

2,500

2,700

2,900

1,900

2,100

2,300

1,500

1,700

1,875

c


+42%yield

increase

WhenSowing:September21,2016Harvest:May8,2017

WhereHubei,China

CropWinter oilseed rape(Brassica napus)


Measurements• Yield• Yield components• Nutrient uptake

30

®

Trial

Oilseed rapeUK

ObjectiveTo investigate an autumn application of Polysulphate to supply sulphurattwodifferentratesontheyieldofoilseedrapevariety Phoenix.

Treatments• Thisisasplitfieldtrial• Polysulphatewasappliedat100kg/haand150kg/ha• Bothrateswerebroadcastatplanting

Results• Application of Polysulphate at 100 kg/ha and 150 kg/ha

intheautumnsignificantlyimprovedtheyieldofwinteroilseedrapeby310kg/haand820kg/ha,onrelativelyhigh yielding crops.

5.2

5.0

4.8

4.6

4.4

4.2

4.0

3.8

3.6

Yiel

d t/

ha

Control Polysulphate 100 kg/ha Polysulphate 150 kg/ha

+19%yield

increase

When2019

WhereNorthYorkshire,UK

CropOilseed rape(Brassica napus cv. Phoenix)


MeasurementsYield

31

®

Trial

Oilseed rapeUK



Results• Application of 100 kg/ha and 150 kg/ha of Polysulphate in

theautumnsignificantlyimprovedtheyieldofrelativelyhighyieldingwinteroilseedrapeby310kg/haand500kg/ha,over the standard farm practice.

5.0

4.9

4.8

4.7

4.6

4.5

4.4

4.3

4.2

4.1

Yiel

d t/

ha


+11%yield

increase

When2019


CropWinter oilseed rape(Brassica napus cv. Phoenix)


MeasurementsYield

32

®

Trial

Oilseed rapeUK



4.8

4.7

4.6

4.5

4.4

4.3

4.2

4.1

4.0

3.9

Yiel

d t/

ha


+13%yield

increase

When2019


CropOilseed rape(Brassica napus cv. Phoenix)


MeasurementsYield

Results• Application of 100 kg/ha and 150 kg/ha of Polysulphate in

theautumnsignificantlyimprovedtheyieldofrelativelyhighyieldingwinteroilseedrapeby370kg/haand550kg/haover the standard farm practice.

33

®

Trial

Oilseed rapeUK

When2019

WhereSouth East UK

CropOilseed rape(Brassica napus cv. Mambo)

Soil typeClay

MeasurementsYield

ObjectiveToinvestigatehowanautumnapplicationofsulphurfromPolysulphate can increase yield by improving establishment beforethewinter.

Treatments• Thisfieldwasasplitfieldtrial• Polysulphatewasappliedtothefieldatplantingatarate

of100kg/ha,thissupplies48kgsulphate(asSO3),14kgpotassium (as K2O),6kgmagnesium(asMgO)and17kgcalcium (as CaO) per ha

Results• Yielddataandmapsfromthecombineshowthatanextra

autumn application of 100 kg/ha Polysulphate increased yieldbyanaverageof263kg/haoverthestandardpractice.

6.5

6.0

5.5

5.0

4.5

4.0

3.5

3.0

Yiel

d t/

ha

Control Polysulphate 100 kg/ha

5.49

5.03

+9%yield

increase

34

®

Trial

OnionTurkey

ObjectiveToinvestigatetheeffectofPolysulphate,potassiumsulphate(SOP)andpotassiumchloride(MOP,KCl)ontheyield,qualityparameters and nutrient uptake of onion.

TreatmentsThisrandomizedtrialconsistedoffourreplicateswithfivetreatments.Nitrogen,phosphorusandpotassiumwereappliedaccording to target yield and soil tests at a rate of 200 kg N ha-1(asureaanddiammoniumphosphate,DAP),170kgP2O5 ha-1 (asdiammoniumphosphate,DAP)and270kgK2O ha-1 (as Polysulphate,SOPorMOP).Anadditionaltreatmentconsistedin K given 50% from SOP and 50% from Polysulphate. Control treatmentreceivedthesameNandPdosesbutnoKwasapplied.

Results• PlanttotaluptakeofN,P,K,Ca,MgandSwerehighestin

thePolysulphatetreatment.Alsomicronutrients’uptake(Fe,Zn,MnandCu)werealsosignificantlyincreasedbyPolysulphate application.

• Nutrientsconcentrationinthebulb(P,K,Ca,Mg,SandFe)werehighestinthePolysulphatetreatment.

• Polysulphate treatment resulted in the highest bulb yield significantlydifferingfromtheothertreatments.Alsobulbweight,bulbheightandbulbdiameterwerehighestatPolysulphate treatment.

• Polysulphateapplicationincreasedthenetreturnandwasveryprofitable,withaB:C(benefit:costratio)of21.2.

• ThehighestvitaminCconcentrationwasfoundinthePolysulphate treatment. Polysulphate also increased antioxidantactivity,phenolsconcentrationandtotalsolublesolids(TSS),whichareveryimportantparametersforonionquality.



Vita

min

C- m

g/10

0g

6.0

6.5

7.0

7.5

8.0

8.5

9.0

10.0

Control Polysulphate

d

abc

bc

ab

a

MOP SOP SOP+Polysulphate

40

50

60

70

80

90

100

110


d

c

abb

a

Bulb

yie

ld -

t/ha

+51%yield

increase

+23%yield

increase

WhenSowing:September 2016 Harvest: May 2017

WhereAntalya,Turkey

CropOnion (Allium cepa)


Measurements• Bulb yield• Quality

parameters• Nutrients uptake

35


®

Trial

OnionThe Netherlands

ObjectiveProve that the use of Polysulphate results in higher bulb yield andqualitycomparedtocurrentgrowerstandardpractices,potentiallyallowingforfewernutrientstobeappliedobtaininggreateryieldsandultimatelyimprovinggrossprofitperacre.

TreatmentsTherateof360kilogramsperhectareofPolysulphate,afertilizerapprovedfororganicfarmingsystems,suppliedadditionalpotassium,magnesiumandcalciumwascomparedwithacontrolwithoutnoadditionalfertilizerapplied.

Onionsaretypicallyfertilizedwithorganicwastes:protoamylaseandvinasse,subproductsofpotatoandsugarindustriesrespectively,bothrichinnitrogenandpotassium.

Anextra50kilogramsperhectareofpotash,asK2O,22kgofMgasMgO,60kgofCaasCaOand69kgofSweresuppliedbythe360kg/haofPolysulphate.

Results• Polysulphate increased total bulb yield by 580 kg/ha.• Halfofthehigheryieldwasinlargerbulbonions(>6cm

diameter),increasingby13%.

Bulb yield per size class (t/ha)<4 cm 4-6 cm > 6 cm Total

Control 4.9 34.1 1.6 40.56Polysulphate 5.2 34.1 1.8 41.14% to control 6% 0% 13% 1%LSD 5% 1.6 3.7 1.3 3.9

Oni

on b

ulb

yiel

d t/

ha

43

41

39

35

37

Bulb size>6cm<6 cm

+13%

+1%

Control Polysulphate

+580 kg/hayield

increase

WhenSowing:20April2016Harvest:29 September 2016

WhereNagele,Netherlands

CropOnion (Allium cepa)

Soil typeClayey soil

Measurements• Total bulb yield • Bulb yield per

category

36

®

Trial

Pack ChoiChina

ObjectiveTo evaluate the addition of Polysulphate and sulphate of potash(SOP)tothefarmers’practiceontheyieldandyieldparametersofpakchoicropgrowninHenanProvince,China.

TreatmentsInthetrialtherewerethreetreatmentswiththreereplicationsarrangedinrandomblockdesign,theareaofeachplotwas30m2.Sowingratewas3kg/ha,Plantdensityinthefieldwas180,000plants/ha.

1. Farmer practice (FP)2.Farmerpractice(FP)+750kg/haofSOP3.Farmerpractice(FP)+750kg/haofPolysulphate

Farmer practice: application of 750 kg/ha of 25-14-6 compound fertilizer as base fertilizer. Topdressing: 150 kg/ha of urea at fastgrowthstage.

ResultsPak choi spread (cm)

Number of leaves per plant

Heightof plant (cm)

Weightper plant (g)

FP 22.9 5.8 28 98.3

FP+SOP 22.7 6.0 29.1 100.5

FP+Polysulphate

21.3 6.5 31.8 108.5

ConclusionsTheapplicationofPolysulphateontopofthefarmers'practice,ascomparedwiththeadditionofSOPandwiththefarmers'practice,increasedplantheight,leafnumberperplant,singleplantweightandyield.

FP+Polysulphate

a

Yiel

d - t

/ha

FP+SOPFP

c b

20

30

40

10

0

Different letters above bars indicate signifi-cant differences among treatments.

Research PartnerCooperation between the Soil and Fertilizer Station of Henan Province and the Land and Fertilizer Mwanagement station of Zhoukou City.

+8%yield

increase

WhenPlanting: 6 May 2016Harvest:30June2016

WhereHuaiyangCounty,ZhoukouCity,Henan,China

CropPack Choi (Brassica rapa subsp. chinensis)

Soil typeFluvo-aquic soil

Measurements• Spread• Number of leaves• Height of plant• Weight per plant• Yield

37

®

Trial

Pack ChoiChina

ObjectiveTo evaluate the addition of Polysulphate and sulphate of potash(SOP)tothefarmers’practiceontheyieldandyieldparametersofpakchoicropgrowninHenanProvince,China.

TreatmentsInthetrialtherewerethreetreatmentswiththreereplicationsarrangedinarandomblockdesign,theareaofeachplotwas30m2.Sowingratewas3kg/ha,plantdensityinthefieldwas180,000plants/ha.

1. Farmer practice (FP)2.Farmerpractice(FP)+750kg/haofSOP3.Farmerpractice(FP)+750kg/haofPolysulphate

Farmer practice: application of 600 kg/ha of 18-18-18 compound fertilizer as base fertilizer.

ResultsNumber of leaves per plant

Heightof plant(cm)

Weightper plant(g)

FP 7.9 20.6 143.8

FP+SOP 8.1 20.9 146.9

FP+Polysulphate 8.6 22.3 156.7

ConclusionsWhencomparingfarmer’spracticewiththeadditionofeitherSOPorPolysulphate,theapplicationofPolysulphateresultedinincreasedplantheight,leafnumberperplant,singleplantweightandyield.

FP+Polysulphate

Yiel

d - t

/ha

FP+SOPFP

24

30

22

20

28

26a

b

b

Different letters above bars indicate signifi-cant differences among treatments.

Research PartnerCooperation between the Soil and Fertilizer Station of Henan Province and the Land and Fertilizer Management station of Shangqiu City.

+5.9%increase

WhenSowing:8May2016Harvest:3July2016

WhereLiuzhuangvillage,ShangqiuCity,Henan,China

CropPack Choi (Brassica rapa subsp. chinensis)


Measurements• Spread• Number of leaves• Height of plant• Weight per plant• Yield

38

®

Trial

Vining peasUK

ObjectiveToinvestigatetheeffectofdifferentratesofPolysulphateonvining peas on a sandy clay loam soil.

TreatmentsThiswasarandomisedtrialoffourreplicateswiththreedifferentapplicationratesofPolysulphate:100,150and200kg/ha.Plotsizewas1.5mx10m.

5

3

1

0Control Polysulphate

100 kg/ha

7

6

4

2



4.735.65

6.30 6.16

Yiel

d - t

/ha

+33%yield

increase

ResultsPolysulphateincreasedtheyieldinallthreedoseswiththeapplicationrateof150kg/hagivingthegreatestresults:a33%yield increase over the control. At 100 kg/ha and 200 kg/ha the yieldincreasedby19%and30%respectively.Usingamarketpriceof£450/tonneforviningpeas,thereturnoninvestmentforthefarmeris£684/ha(€773/ha)applying150kg/haofPolysulphate.

WhenSowing:April6,2017Harvest:June25,2017

WherePGRO Research Centre,England

CropVining peas(VarietyJubilee)


MeasurementsYield

39

®

Trial

PeasUK

ObjectiveToinvestigatetheeffectofapplicationofPolysulphateonviningpeas.Specifically,toincreasetheyieldandtoseeifseedratesarehigherwouldthisimproveoverallyield.ThephasedreleaseofsulphatefromPolysulphateshouldhelpwiththeformationofnitrogenfixingnodulesintherootsofthepeacrop.

Treatments• Thistrialwasasplitfieldtrial• Polysulphatewasappliedatarateof150kg/haatdrilling

Results• Theaverageyieldforthefieldwas8t/hawhenallareas

wereaveraged.Polysulphateincreasedtheyieldby1.2t/haoverthestandardfarmpracticeandwhentheseedcoatingis added the yield improved to 1.9 t/ha over the control

• The satellite images had higher NDVI (green and blue colors) inthePolysulphatestrips,thusshowingdenservegetationthan the farm practice

12

10

8

6

4

2

0

Yiel

d t/

ha

Control

8.1


9.310.0

Polysulphate 150 kg/ha and seed coating

Treatments in the trial field

NDVI after 40 days

Control

Polysulphate150 kg/ha

Polysulphate150 kg/ha and seed coating

2.75-3.003.00-3.253.25-3.503.50-4.004.00-4.504.50-5.005.00-6.00>6.00

<0.50 0.50-1.001.00-1.501.50-1.751.75-2.002.00-2.252.25-2.502.50-2.75

IBI

Normalized Difference Vegetation Index (NDVI) describes the difference between visible and near-infrared reflectance of vegetation cover and is used to quantify vegetation. NDVI is derived from remote-sensing (satellite) images.

+23.5%yield

increase

When2018

WhereLincolnshire,UK

CropPeas (Pisum sativum cv.Amalfi)

Soil typeLight to medium deep silt

Measurements• NDVI• Yield

40

®

Trial

Combining peas UK

ObjectiveToinvestigatetheeffectofdifferentratesofPolysulphateoncombining peas on a sandy clay loam soil.

TreatmentsThiswasarandomisedtrialoffourreplicatesthathadthreedifferentapplicationratesforPolysulphate:100,150and200kg/ha.Plotsizewas1.5mx10m.

ResultsOfthethreePolysulphateapplicationratestested,thebestresultwasachievedwhenPolysulphatewasappliedat100kg/ha.Thisresultedinayieldincreasedofapproximately8%(0.35tonnesperhectare).Basedonamarketpriceof£180/tonnethisrepresentsanadditionalreturnof£62.28perhectare.

4.4

4.2

4.0

3.9Control Polysulphate

100 kg/ha

4.6

4.5

4.3

4.1

Yiel

d - t

/ha

+8%yield

increase

WhenSowing:April7,2017Harvest:July31,2017

WherePGRO Research Centre,England

CropCombining peas (Variety Crackerjack)


MeasurementsYield

41

®

Trial

PeanutVietnam

ObjectiveToevaluatetheeffectsofpotassium(K)andPolysulphateapplication rates on peanut agronomic and economic performancesforthegrowingconditionsintheCentralCoastof Vietnam.

TreatmentsTheexperimentwassetaccordingtoarandomizedcompleteblockdesign(RCBD)withfourreplications.Sixfertilizationtreatmentsweretested:Farmers’practice(FP)control,withN:P:Kratioof95:40:100;NP-K0,with45kgN/ha,90 kg P2O5/ha,andzeroK;andNP-K30;NP-K30-S1;NP-K60-S2,and NP-K90-S3,allofwhichwereappliedwithsimilarNandPrates,Kratesincreasingfrom30to90kgK2O/ha,andPolysulphate at 107 (S1,25kgS/ha),214(S2,50kgS/ha),and321kgha–1 (S3,75kgS/ha),respectively.NitrogenwasappliedthroughureaandPthroughsuperphosphate.Potassiumwasapplied through KCl and Polysulphate.

Results• FP and NP-K0 displayed the poorest performance in most

parameterstestedandobtainedlowpeanutyieldandbenefit.

• TheoptimumtreatmentwasachievedwithNP-K60-S2

(214kgPolysulphate/ha),whichresultedinayieldof2.86 t/haofgrains,24%morethanthefarmers’practice,andina

98%increaseinthenetbenefittothefarmer.• Soiltestsbeforesowingandafterharvest,indicatedthat

whileFPsignificantlyreducedsoilfertility,Polysulphateledto enhanced soil fertility.

0.0 0

0.5 5

1.0 10

1.5 15

2.0 20

2.5 25

3.0 30

3.5 35

FP

cd cd

bd

a ab

d

NP K0 NPK30

kg Polysulphate/ha

NPK30S1107

NP K60 S2214

NP K90 S2321

Net

yie

ld -

t/ha

Net

inco

me

- Mill

ion

VND

/ha

Net yield Net income


WhenSowing:April2016Harvest:September 2016

WhereBinhDinhProvince,Vietnam

CropPeanut (Arachis hypogaea L.)

Soil typeSandy acidic soil

Measurements• Yield• Crop development• Soil tests before

sowingandafterharvest

+24%yield increase

+98%net benefit

increase

42


®

Trial

PineappleMalaysia

WhenJanuary2017to May 2017

WhereSimpangRenggam,Johor,Malaysia

CropPineapple (Ananas comosus)

Soil typePeat

Measurements• Yield• Fruit grade

ObjectiveTodeterminetheeffectivenessofgranularPolysulphatetoimprovethegrowthandyieldofpineapplesonpeatsoil.

TreatmentsTreatment Fertilizer RateControl Compound fertilizer

(13-13-21+TE)500 kg/ha

Polysulphate Granular Polysulphate(0-0-14+48%SO3+6MgO+17CaO)

500 kg/ha

Results• Inthecontrolplot,themajorityofplantsshowedsymptoms

ofKdeficiencyduringthefruitingstage,whiletheplantsinthePolysulphateplothadfewerKdeficiencysymptoms.

• PlantstreatedwithPolysulphatehadbiggerleavesandfruit.• Polysulphate application increased the sugar content in fruit: in

controlplotstheBrixlevelwas13-16%comparedto16-19%withPolysulphate.

• Fruit from the Polysulphate plots had a longer shelf life.• Totalyieldwassimilarforbothplots,buttherewasan11%

increaseingradeAfruits(>660gperpiece)inthePolysulphateplot compared to the control plot.

3500

3000

2500

2000

1500

4500

4000

0

1000

500

Grade AGrade BGrade CGrade DGrade E

Compound fertilizer Polysulphate

Frui

t qua

ntity

bas

edon

frui

t gra

de

Without Polysulphate With Polysulphate

+11%Grade A yield

increase

43

®

Trial

PomegranateChina

Different letters above bars indicate signif-icant differences among treatments (P<0.05)

ObjectiveTocomparetheyieldandqualityofpomegranatefruitsgrowninHenanProvince,Chinausingfarmers’fertilizerpracticeorfertilizerschemesbasedonsoiltestsandeitherwithorwithouttheadditionofPolysulphate.

TreatmentsThetrialtestedtheeffectofthreedifferentfertilizertreatmentsonpomegranatetreesofeither10,15,or20yearsold.Therewerethreereplications for each treatment.1. FFP(farmer’sfertilizerpractice):basefertilizerinautumn:7,500kg/ha

organicfertilizer;topdressingfertilizerinspring:500kg/haN,500kg/haP2O5 and 500 kg/ha K2O

2. STFF (soil testing and formula fertilization): base fertilizer in autumn: 7,500kg/haorganicfertilizer;topdressingfertilizerinspring:373.5kg/haN,223.5kg/haP2O5and327kg/haK2O

3. STFF+PS(soiltestingandformulafertilization+Polysulphate):basefertilizerinautumn:7,500kg/haorganicfertilizerand375kg/haPolysulphate;topdressingfertilizerinspring:373.5kg/haN,223.5kg/haP2O5and327kg/haK2O

Results• Comparedwithfarmers’fertilizerpractice,usingsoiltestingand

formulafertilizerswithPolysulphatesignificantlyincreasedfruityieldforpomegranatetreesofallages.Theyieldincreaseislesssignificantastreeageincreases,82.4%(10years),55.2%(15years)and30.5%(20years).

• Polysulphatesignificantlyincreasedthenumberoffruitspertree,fruitweightandfruitsize.

• Polysulphatesignificantlyincreasedsugarcontent,sugar-acidratioandvitaminCcontent,whiledecreasingacidityofthefruits.

• Comparedwithfarmers’fertilizerpractice,usingsoiltestingandformulafertilizerswithPolysulphateforpomegranatetreesincreasedfarmers’netincomeby148.29%,84.42%and47.61%for10,15,and20yearoldtrees respectively.

Tree-age (year)

Treatment Diameter (cm)

Sugar Content (%)

Acidity (%)

Sugar acid ratio

Vitamin Ccontent(mg/kg)

10 FFP 8.40 b 14.91 b 0.28 a 53.14b 5.72 bSTFF 8.84 a 15.10 ab 0.16 b 92.26 a 7.29 aSTFF+PS 8.70 a 15.77 a 0.16 b 96.36a 7.41 a

15 FFP 8.11 b 14.26 b 0.23a 60.99 b 6.70 bSTFF 8.34ab 14.97 ab 0.19 ab 80.03a 7.99 aSTFF+PS 8.57 a 15.03a 0.17 b 88.44 a 7.88 a

20 FFP 8.35b 14.73a 0.28 a 52.50 b 5.79 bSTFF 8.67 a 14.66 a 0.18 b 81.50 a 7.85 aSTFF+PS 8.58 ab 15.09 a 0.21 b 72.76 a 7.92 a

Frui

t yie

ld (t

/ha)

35

30

25

40

15

20

10 years

b

a

a

15 years

c

b

a

20 years

b

aa

FFPSTFFSTFF+Polysulphate

When2016

WhereHeyin,HenanProvince,China

CropPomegranate(Punica granatum)

Soil typeCalcareous

Measurements• Yield • Number of fruits

per tree• Fruitweight• Fruit quality

+82.4%yield

increase

+55.2%yield

increase

+30.5%yield

increase

44

®

Trial

Honey pomelo China

ObjectiveToinvestigatetheeffectofPolysulphateontheyield,qualityparameters and spring shoot parameters of honey pomelo.

TreatmentsThistrialconsistedofthreetreatmentswith12plantspertreatment.Thetreatmentswere:(1)farmers’practice(pigmanure+NPKfertilizeratatotalrateof1,528,1,016and1,246kg/haofN,P2O5 and K2Orespectively,splitin5applications),(2)Optimizedfertilization(organicfertilizer+NPKfertilizeratatotalrateof862,631,744,69and49kg/haofN,P2O5,K2O,CaOandMgOrespectively,splitin4applications),and(3)Optimizedfertilization+Polysulphate(organicfertilizer+NPKfertilizer+Polysulphateatatotalrateof862,631,1038,468and175kg/haofN,P2O5,K2O,CaOandMgOrespectively,splitin 4 applications).

Results• Comparedwithfarmers’practice,Polysulphateapplication

increasedthenumberofspringshootsby23%andthebiomass of spring shoots

by 19.7%.

• Polysulphate application increased the fruit yield by 6.9% whencomparedtothefarmers’practice,andby1.2%whencompared to the optimized fertilization treatment.

• Polysulphateapplicationincreasedthequalityparameters,speciallythefreshweightperfruit,fleshweightandfruitdiameter.

• Comparedwithfarmers’practice,PolysulphatetreatmentreducedtheN,PandKinputsby44,38and17%respectively,thusdecreasingfertilizercostsby11%andincreasingfarmers’incomeby7%whencomparedtofarmers’practice.

Treatments

Farmers’practice Optimized fertilization Optimized fertilization+Polysulphate

Yiel

d (t/

ha)

40

45

50

55

60

+6.9%yield

increase

WhenTree age: 5 yearsHarvest:October,2017

WhereFujian,China

CropHoney pomelo (Citrus maxima)

Soil typeLateritic soil

Measurements• Yield• Fruit quality

parameters• Spring shoot

parameters

45

®

Trial

PotatoColombia

ObjectiveToevaluatetheeffectivenessofpartiallyreplacing(upto50%)themostcommonfertilizer(NPK10-20-20)withPolysulphatetobetterbalancetheplants’nutrition,especiallyintermsofsulphur supply.

TreatmentsAgeneralfertilizationwith900kg/haofacomplexfertilizer(14-30-15+1Mg+1Ca)wascarriedoutatplanting.Then,treatmentswereappliedat45daysafterplanting:1)Farmers’practice:900kg/haofacomplexfertilizer(12-21-21+1.4Mg+2.2Ca);2)900kg/haofanNPKfertilizer(10-20-20);and3)450kg/haofPolysulphateincombinationwith450 kg/ha of 10-20-20 (50:50).

Results• The combined Polysulphate and NPK treatment increased

thetotalyieldby4%comparedwiththefarmers’practice.• The combined Polysulphate and NPK treatment resulted in an

increaseinthenumberoflargetubers;20%morefirstclass(large)tubersand23%lessthirdclass(small)tubers.ThiseffectmightbeassociatedwithhigherproportionsofCaandMgaswellasthesulphureffect,whichimprovestheN:Sratio.

• The combined Polysulphate and NPK treatment increased the totalincomeby13%comparedwiththefarmers’practice.

• The combined Polysulphate and NPK treatment increased thebenefit:costratioto11%andconstitutesagreatoptionforfarmerstoimprovetheprofitabilityoftheircrops,especially as increased tuber size provides greater access to markets at any time of the year.

Yiel

d (k

g/ha

)

10000NPKCaMg NPK (0)

Treatment (Proportion Polysulphate: 10-20-20)

NPKCaMgS (50:50)

15000

20000

25000

30000

35000

40000

45000

50000

-23%

+4%FirstThirdTotal

Bars indicate average and standard errors

6.0

6.5

7.0

8.0

7.5

8.5

Bene

fit/Costratio

NPK (0)

Treatment (Proportion Polysulphate: 10-20-20)

-6%

NPKCaMg NPKCaMgS (50:50)

+11%

WhenPlanting:February 2018Harvest:June2018

WhereTotoró,Cauca,Colombia

CropPotato (Solanum tuberosum) Variety: Criolla

Soil typeAndisol,sandyloam

Measurements• Yield• Tuber size

+20%yield

increase of large tubers

46

®

Trial

PotatoChina

ObjectiveToevaluatetheeffectofPolysulphateapplicationincombinationwithsulphateofpotash(SOP)onpotatoyieldinChina.

TreatmentsTheexperimentwassetaccordingtoacompleterandomizedblockdesignwith3replications.AKdoseof300kgK2O/hawastestedindifferentcombinationsofSOPandPolysulphate:1)control,with300kgK2O/ha asSOP;2) 90 kg K2O/haasSOPcombinedwith210kgK2O/ha as

Polysulphateand;3)234kgK2O/haasSOPcombinedwith66kgK2O/ha as

Polysulphate.NitrogenandPwereappliedatsowingforalltreatments.

Tube

r yie

ld (k

g/ha

)

20,000Control (SOP) 90 kg K2O/ha as SOP

+210kgK2O/ha as Polysulphate

25,000

30,000

35,000

40,000

45,000

50,000

55,000

60,000

YieldDisease

Dis

ease

inde

x

234kgK2O/ha as SOP +66kgK2O/ha as

Polysulphate

4

6

8

10

12

14

16

18

Results• Thecombinedtreatmentof234kgK2O/ha as SOP combined

with66kgK2O/ha as Polysulphate increased the total yield by21%whencomparedtothecontrol.Tubernumberperseedlingwasthehighestatthistreatment.

• BoththeaveragetuberweightandthepercentageoflargetuberswereincreasedbythecombinedapplicationofPolysulphateandSOPwhencomparedtoSOPalone.

• The combined application of Polysulphate and SOP promotedstarchaccumulationinpotatotuber,butdidnotaffectthesugarcontentoftubers.

• Thecombinedtreatmentof234kgK2O/haasSOPwith66kg K2O/ha as Polysulphate decreased the index of common scab disease from 16.4% in the control treatment to 6.7%.

WhenPlanting:4May,2018Harvest:29August,2018

WhereChayouzhongcounty,InnerMongolia,China

CropPotato (Solanum tuberosum)Variety: Kexin No.1

Soil typeSandyloam,pH8.0

Measurements• Yield• Tuber size

+21%yield

increase

47

®

Trial

PotatoUSA

ObjectiveToevaluatePolysulphateasasubstitutepotassium,calcium,andsulphurfrommuriateofpotashandgypsuminconventionalpractice,forpotato‘RussetBurbank’grownincentral Wisconsin.

TreatmentsGrowerpracticeconsistsof37kgN/haappliedatplantingasDAP.Atemergenceandactivegrowth,85and190kgN/hawasapplied,respectivelyasammoniumsulphateandammoniumnitrate.Phosphorus,derivedfromDAP,wasappliedat185kgP2O5/haatplanting.Potassiumwasappliedpre-plantat310kg K2O/haasMOP,andat135kgK2O/ha as SOP at planting. In addition,atpre-plantgypsumwasappliedat560kg/ha.

ThePolysulphatetreatmentwasaduplicateofthegrowerpracticewithoutthepre-plantMOPandgypsum.Instead,Polysulphatewasappliedat1,680kg/haatpre-plant.

Results• Polysulphate fertilization increased the marketable ideal*

yieldby1.79ton/haoverconventionalgrowerpractice

• Marketableyieldincreasedby15%withtheadditionofPolysulphate

* The ideal yield is 6-16 oz or grades 2-4. Marketable yield excludes hollow tubers.

0

5

10

Mar

keta

ble

yiel

d (to

n/ha

)

15

Growerpractice308N-185P2O5 - 448 K2O -

165 CaO - 216 S kg/ha

TreatmentwithPolysulphate308N-185P2O5-375K2O -

100MgO-293CaO-443Skg/ha

+15%yield

increase

WhenPlanting:15May,2018Harvest:4October,2018

WhereWisconsin,USA

CropPotato (Solanum tuberosum cv. Russet Burbank)

Soil typeAcidic,loamysandsoil

Measurements• Yield• Quality

48

®

Trial

PotatoThe Netherlands

ObjectiveTo prove that the use of Polysulphate results in higher tuber yieldandqualityofwarepotatoescomparedtocurrentgrowerstandard practices.

Treatments• TheuseofPolysulphateatplanting,atarateof1,053kg/ha,

wastestedasasourceofmagnesium,anutrientabsentofthe current standard practice.

• 65kilogramsperhectareofMgasmagnesiumoxide(MgO),wassuppliedbyPolysulphate.

Results• TheuseofPolysulphateresultedinasignificantlyhigher

potatoyieldcomparedwiththecontrol(SOP)treatment.• Thelargersignificantdifferenceswereobservedon

marketabletubers(+2.2%),andespeciallywithlargertubers(+3.3%).

• Nosignificanteffectwasobservedontuberdensity,anindicator of industrial quality.

Pota

to tu

ber -

t/ha

Commercial Superior>5cm

+1.8t/ha

+1.4t/ha

60

65

70

50

55

45

40

Control (SOP)

Polysulphate

When2016

WhereVredepeel,TheNetherlands

CropPotato (Solanum tuberosum)

Soil typeSandy soil

Measurements• Tuber yield• Tuber size

+2.2%yield

increase

+3.3%yield increase

of large tubers

49

®

Trial

PotatoGreece

ObjectiveThistrialinNorthernGreececomparedtheyieldofpotatoesgrownwithanimprovedICLfertilizerpackage,whichincludedPolysulphate,topotatoesgrownusingthestandardlocalfarmers'practice.

Yiel

d (t/

ha)

ICLpracticewithPolysulphate

44

46

48

50

52

54

56

58

Farmers' practice

TreatmentsThefarmers’practiceconsistedofabasalapplicationof1,100kg/ha ofcompoundfertilizer14-14-14+26SO3+2MgO;atopdressingof 300kg/haofpotassium-magnesiumsulphate(0-0-30+42SO3+10MgO)and200kg/haof40-0-0+14SO3;80kg/haof20-19-19and 80kg/haof12-6-36+TEappliedthroughfertigation;and2.5kg/haof3-27-18+seaweedappliedasafoliarsprayed.Intotal259.6kgN/ha,174 kg P2O5/ha,288kgK2O/ha,440kgSO3/haand52kgMgO/hawereapplied to the crop.

TheimprovedICLpracticeincludedthesamebasalfertilization; a top dressing of 500 kg/ha of Polysulphate and 200 kg/ha of 40-0-0+14SO3;and100kg/haofICL"Solinure"11-35-11+2MgO+TEand250kg/haofICL"NovaNPK"10-10-40+TEappliedthroughfertigation.Intotal270kgN/ha,214kgP2O5/ha,335kgK2O/ha,554kgSO3/ha,54kgMgO/haand85kgCaO/hawereappliedtothecrop.

Results• The improved Polysulphate practice increased potato yield by 16%.• Netincomeforthepotatogrowerusingtheimprovedpracticeincreasedby15%whencomparedtothestandardpractice.

+16%yield

increase

WhenPlanting: April 2019Harvest:October 2019

WhereKozani,Greece

CropPotato (Solanum tuberosum) cv. Spunta

Soil typeClay soil

MeasurementsYield

50

Trial

ObjectiveToinvestigatehowICLPotashpluScomparestomuriateofpotash(KCl,MOP)asasourceofpotassiumforprocessingpotatoes.

Treatments• Thiswasasplitfieldtrial.• ICLPotashpluSandMOPwereappliedtoprovidethesame

applicationrateofpotassium:340kgK2O/ha.• Bothfertiliserswerebroadcastandincorporatedpriorto

planting.

Results• ICL PotashpluS gave a 8% increase in yield over the MOP.

Thisisattributedtothesolublemagnesium,sulphurandcalciumsuppliedbyICLPotashpluS,evenwhenthesoilwasnotmagnesiumdeficient.

• ThetuberdrymatterwashigherintheICLPotashpluStreatment(20.6%)thanwhereMOPwasapplied(19.8%).Drymatterisavaluablebenefitforprocessingpotatoes.

• TheICLPotashpluStuberswerejudgedtobemoreconsistentinsize,showinglessvariation.

Tuber yield increase Tuber dry matter

DM

- %

21.0

20.0

19.5

20.5

19.0

18.5

18.0MOP ICL PotashpluS

Yiel

d - %

ICL PotashpluSMOP

105

95

90

110

100

When2017


CropPotato (Solanum tuberosum)

Soil typeLoam

Measurements• Yield• Tuber dry matter

(% DM)

+8%yield

increase

PotatoUK

51

®

Trial

PotatoPeru

ObjectiveToevaluatetheeffectofPolysulphateasacomplementaryKand S source on potato yield and tuber size.

TreatmentsThistrialwasestablishedunderarandomizedblockdesignwith4replicationsandincludedfivesplitPolysulphatedoses(0,140,280,420,and700kg/ha)appliedandincorporatedatplanting and earthing up 45 days later. All treatments received atotalNPKapplicationof250,150and200kg/hafromurea,DAPandKCl,usingPolysulphateasacomplementaryKsourcethat reduced the KCl.

Results• Apositiveeffectonyieldandtubersizeupto700kg/haof

Polysulphatewasobserved.• Polysulphatesignificantlyincreasedtotalyieldby7to12%

comparedtothecontrolwithoutPolysulphate.• Addition of S from Polysulphate improved tuber size by 5 to

13%.• The recommended application rate for potato production in

HuancabambaStateis300-400kg/haofPolysulphateplusanextraMgOdoseof30Kg/ha.

Pota

to y

ield

t/ha

30

25

20

35

10

15

TotalLarge size


Bars indicate standard errors of the four replications of each treatment


0 140

12%

12%

280

7%

5%

420

7%

13%

700

10%

11%

WhenPlanting:July2017Harvest:December 2017

WhereHuancabamba,PiuraState,Peru

CropPotato (Solanum tuberosum var. Amarilis)

Soil typeAndisol,clayloam

Measurements• Total yield• Yield class based

on tuber size

+12%yield

increase

52



®

Trial

Sweet potatoUSA

ObjectiveTocomparetheeffectonsweetpotatoyieldofreplacingthefarmers’practicefertilizerblendwithablendwhichcontainsPolysulphate,inNorthCarolina,USA.

TreatmentsFarmers’practiceconsistedofablendofDAP,MOPandpotassium-magnesiumsulfate,givingadoseof21lbs.N,55lbs. P2O5,200lbs.K2O,15lbs.Sand7lbs.Mgperacre.

ThePolysulphatetreatmentconsistedofablendofDAP,MOPandPolysulphate,givingadoseof23lbs.N,58lbs.P2O5, 200 lbs. K2O,51lbs.S,9lbs.Mgand33lbs.ofCaperacre.

Theseblendsweappliedtwoweeksaftersetting.Bothtreatments had liquid UAN (urea ammonium nitrate) side-dressed at mid-season.

Treatments

Yiel

d (b

u/ac

re)*

400

420

440

460

480

500

520

540

There are 56 #1 potatoes in a bushel

Farmers’blend BlendwithPolysulphate

+7%yield

increase

Results• Comparedwithfarmers’fertilizationpractice,usingablend

withPolysulphateincreasedsweetpotatoyieldby7%andincreased#1sby30bushels/acre.

• TheresultsshowedthatwithequalamountsofN,P,andKthereisabenefitfromPolysulphateduetothehigherrateofplant-availablesulfurandcalcium.Also,theprolongedavailability of the nutrients in Polysulphate may contribute to the enhanced yields.

WhenSowing:May2019Harvest:September 2019

WhereKenly,NorthCarolina,USA

CropSweetpotato (Ipomoea batatas)


MeasurementsYield

53

®

Trial

PotatoColombia

ObjectiveToevaluatetheeffectofPolysulphate,appliedinoneandtwoapplications,asacomplementarynutrientsourceonpotatoyield and tuber size.

TreatmentsThistrialconsistedoftwentyrows,eachestablishedwithoneoffourPolysulphatetreatments.Polysulphatewasappliedandincorporated at planting and 45 days later at earthing up in 4 treatments:1)NoPolysulphate;2)510kg/hasplitatplantingandearthingup;3)790kg/hasplitatplantingandearthingup;4) 790 kg/ha at planting.

AlltreatmentsreceivedatotalNPKapplicationof210,400and290kg/ha,usingPolysulphateasacomplimentaryKsourcethat reduced the other K sources (12-24-12 and 12-21-21).

Results• Apositivetrendlineofyieldandtubersizewithincreasing

dosesofPolysulphateupto790kg/hawasobserved.

• Polysulphatesignificantlyincreasedtotalyieldupto27%comparedtothecontrolwithnoPolysulphate.

• AdditionofK,Ca,MgandSfromPolysulphateimprovedtubersizeby6to35%.

• Asplitdosewouldnormallyperformbetter,butduetothedryconditionsduringthetrial,thesingleapplicationof790kg/ha at planting resulted in higher yields compared to the same split dose.

• The recommended application rate for potato production in Cauca State is 500-600 kg/ha of Polysulphate.

Pota

to y

ield

t/ha

40

35

30

45

20

25


0 510 split

b6%

790 split

50

60

55

TotalLarge size

b

b

b15% b

6%

ab16%

a35%

a27%

790-at planting

WhenPlanting:September 2018Harvest: April 2019

WhereTotoró,CaucaState,Colombia

CropPotato (Solanum tuberosum var. Parda)

Soil typeAndisol,sandyloam

Measurements• Total yield• Yield class based

on tuber size

Bars indicate standard errors of the four replications of each treatment

Different letters indicate significant differences among treatments by Tukey test (P=0.05)

+27%yield

increase

54

®

Trial

PotatoUSA

ObjectiveEvaluatePolysulphateassubstituteforthepotassium,calcium,andsulfur from muriate of potash and calcium sulfate in conventional practice,forpotato‘RussetBurbank’grownincentralWisconsin.

TreatmentsSize‘B’RussetBurbankpotatoseedwereplantedatarateof14,520seedsperacreata6-inchdepthwith12inchesinrowand36inchesbetweenrowspacing.Thepotatoeswereharvestedata6-footwidthusinga1rowpotatodigger.

Forgrowerpracticeperacrenitrogenwasappliedat33poundsatplanting,76poundsatemergence,119and51poundsduringactivegrowthderivedfromDAP,AS,andammoniumnitrate,respectively.Phosphatewasappliedat165poundsperacreatplantingderivedfrom DAP. Per acre potassium (K2O)wasappliedas276poundspre-plant,and121poundsatplantingandwasderivedfromMOP,andMOPwithSOP,respectively.Inaddition,gypsumwasappliedpre-plant at 500 pounds per acre.

ThePolysulphatetreatmentwasaduplicateofthegrowerpracticewithoutthepre-plantMOPandgypsum.Polysulphatewasappliedat1500poundsperacrepre-plantsupplying334poundsperacreK2O,andthefullseason’ssupplyofcalciumandsulfur.

Results• Polysulphate fertilization increased the marketable ideal* yield by

16hundredweightperacreoverconventionalgrowerpractice• Yieldtofertilizerratiofornitrogenincreasedby14%withthe

addition of Polysulphate• ThevaluecostratioofaddingPolysulphatewas$13.14forevery

$1spent• Grossincomeperacreincreasedby$448withtheadditionof

Polysulphate* The ideal yield is 6-16 oz or grades 2-4. Marketable yield excludes hollow tubers.

95

100

105

110

115

120

Marketableyield(cwt·ac-1

)

125

Growerpractice275 N - 165 P2O5 - 400 K2O -

105Ca-193Slb·ac-1

Polysulphate275 N - 165 P2O5-335K2O - 54 Mg -

188Ca-395Slb·ac-1

105 cwt · ac-1Growerpractice $13.14 for every

$1spentonPolysulphate

Yield Gross Income Value Cost Ratio

121 cwt · ac-1Polysulphate

$ 2,940Growerpractice

$ 3,388Polysulphate

$13.14

WhenPlanting:May15,2018Harvest:October4,2018

WhereAgRes,LLCHancockWisconsin,USA,DavidWenner

CropPotato (Solanum tuberosum cv. Russet Burbank)

Soil typeAcidic,loamysandsoil

Measurements• Yield • Quality

+14%yield

increase

55

®

Trial

PotatoThe Netherlands

ObjectiveProve that the use of Polysulphate results in higher tuber yield andqualitycomparedtocurrentgrowerstandardpractices.

Treatments• TheuseofPolysulphatewascomparedwithkieseriteto

supplymagnesium,thecurrentstandardpractice.• 47kg/haofMgasmagnesiumoxide(MgO),wassuppliedby

both sources.• Therateof791kg/haofPolysulphate,suppliedadditional

potassiumandcalciumthatwerecomparedwiththecontrolwithkieserite.

Results• TheuseofPolysulphateresultedinasignificantlyhigher

potatoyieldwhenusedasMgsourceinsteadofkieserite.• Increasedtotalbulbyieldby3.3t/ha.• Higheryieldwasfoundineveryclassgradeyield,aswellas

innumberoftubers,increasingby5%.• Nosignificanteffectontuberdensity,asindicatorof

industrial quality.

Pota

to tu

ber y

ield

t/ha 60

55

50

65

40

45

>7cm<7 cm

+6%

+5%

Kieserite Polysulphate

+3.3 t/hayield

increase

WhenPlanting: May 2016Harvest:October 2016

WhereLelystad,TheNetherlands

CropPotato(Solanum tuberosum)

Soil typeClayey

MeasurementsTuber yield

56

®

Trial

RiceUSA

ObjectiveToevaluatePolysulphateasafertilizersourcefor‘CL153’ricegrowninsandy,silt-loamsoilsinsouthernLouisiana,USA.

TreatmentsThistrialcomparedricegrowusinggrowerstandardpractice,andgrowerstandardpracticewithPolysulphate.

Growerstandardpracticeconsistedof157kgN/haintheformofurea,112kgN/haatpre-flood,and45kgN/haatgreenring.Phosphoruswasappliedpre-floodat112kgP2O5/ha from DAP andSuperPK.Potassiumwasappliedpre-floodat67kgK2O/haperacrefromSuperPK.ThePolysulphatetreatmentwasaduplicateofthegrowerstandardpracticewiththeadditionof196kgPolysulphate/haappliedpre-flood.

Lines indicate standard error (SE)

6,000

6,500

7,000

7,500

8,000

9,500

9,000

11,000

10,500

10,000

Gra

in y

ield

(kg/

ha)

Growerstandardpractice157 N - 112 P2O5 - 67 K2O kg/ha

Polysulphate treatment157 N - 112 P2O5 - 95 K2O -

38S-11MgO-33CaOkg/ha

8,500

Results• Polysulphateincreasedriceyieldby534kg/ha(5.5%)over

growerstandardpractice.

WhenPlanting:March15,2018Harvest:July25,2018

WhereLSU AgCenter Rice ResearchStation,Rayne,Louisiana,USA

CropRice (Oryza sativa)

Soil typeSandy,silt-loamsoil

MeasurementsYield

+5.5% yield

increase

57

®

Trial

RiceEcuador

ObjectiveToevaluatetheeffectofPolysulphate,asacomplementaryKandSsourcepartiallysubstitutingKCl(MOP)fertilizer,onriceyield,harvestindex,grainqualityandsheathrotincidence.

TreatmentsThisrandomizedblocktrialconsistedoftwentyplotswiththreePolysulphatedoses(0,160and240kg/ha)plustwoammonium sulphate doses (129 and 192 kg/ha) applied incorporated at planting and 15 days later. All treatments receivedatotalNPKapplicationof140,20and60kg/hafromurea,DAPandKCl.PolysulphatewasusedasacomplementaryKsourcethatreducedtheKClapplication,andasulphursourcetobecomparedwithammoniumsulphate.

Results• Polysulphate and ammonium sulphate both increased rice

yieldby2.5%,butPolysulphateincreasedharvestindexbyup to 11%.

• AsignificantpositiveeffectongrainqualityanddiseasetoleranceinricewasobservedwithPolysulphateapplications of up to 240 kg/ha.

• AdditionofSfromPolysulphatereducedwhitecenteringrains by 15 to 19% and diminished Sarocladium incidence by up to 66%.

• The recommendation for the Guayas region is that Polysulphate applied at planting at a rate of 150-200 kg/ha willimprovericeproductivityandgrainquality.

Bars indicate standard errors.


Whi

te c

ente

r in

grai

ns (%

)

Saro

clad

ium

inci

denc

e

24

22

20

18

16

14

12

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Fertilizer dose (kg/ha)0 160 129240 192

Yiel

d (k

g/ha

)

Har

vest

Inde

x

9500

9000

8500

8000

7500

7000

0.80

0.76

0.72

0.68

0.64

0.60

Fertilizer dose (kg/ha)0 160 129240 192

PolysulphateAmmonium sulphateHarvest Index

PolysulphateAmmonium sulphateSarocladium

WhenPlanting:September 2018Harvest: February 2019

WhereYaguachi,Guayas,Ecuador

CropRice (Oryza sativa var. INIAP FL Cristalino)

Soil typeInceptisol,loamwithneutralpH(6.9),lowOM (1.2%) and high K,Ca,Mg,andNacontent.

Measurements• Yield and Harvest

Index• White center

presence in grains and Sarocladium (sheath rot) incidence

+2.5% yield

increase

58


®

Trial

Rocket saladItaly

ObjectiveToinvestigatetheeffectofPolysulphateontheyieldofgreenhousegrownrocketsalad.

Farmers’practice:Organicfertilizer1,500kg/ha

14-7-17350kg/ha

Organicfertilizer1,500kg/haAgromaster11-18300kg/ha

Polysulphate 600 kg/haDifferent letters within columns indicate statistically significant differences

Organicfertilizer1,500kg/haAgromaster 15-24-10 400 kg/ha


Cum

mul

ativ

e yi

eld

(t/ha

)

0

5

10

15

20

25

30

35

40

45

a bc

WhenSowing:October,2016Harvest:October,2017

WhereCampania,Italy

CropRocket salad (Eruca sativa)

Soil typeSilt-loam soil

Measurements• Fresh yield• Dry matter yield

+8.2%yield

increase

TreatmentsThistrialconsistedofthreetreatmentswithfourreplicatesinarandomizedcompleteblockdesign.Thetreatmentswere:(1)Farmers’practice:1,500kg/haoforganicfertilizer+350kg/haof14-7-17NPKfertilizer.(2)1,500kg/haoforganicfertilizer+300kg/haofAgromaster11-48+600kg/haofPolysulphate.(3)1,500kg/haoforganicfertilizer+400kg/haofAgromaster15-24-10+600kg/haofPolysulphate(AgromasterisICL’scontrolledreleasefertilizer).Allfertilizerswereappliedbeforesowing.Thecropwasharvestedon8successivedates.

Results• ThecumulativeyieldsinthePolysulphatetreatmentswere

significantlyhigherthanthefarmers’practice(+1.58and+2.85t/harespectively).Thedifferenceswereevidentrightfrom the 1st harvest.

• Fromthe3rdharvestonwards,thetreatmentswithPolysulphate produced higher dry matter yield per hectare. This parameter is essential to increase the shelf life of the rocket salad after harvesting.

• Thereturnoninvestment(ROI)washigherinbothPolysulphatetreatmentswhencomparedwiththefarmers’practice:1,630€/haforthePolysulphatetreatment(1)and3,390€/haforPolysulphatetreatment(2).

59

®

Trial

SesameIndia

CD (P=0.05): 0.045 (seed); 0.140 (stover)


ObjectiveTotesttheefficacyofPolysulphateasasulphursourceontheperformance of sesame crops in India.

TreatmentsTheexperimentwaslaidoutinarandomizedblockdesignwiththreereplicates and included six treatments:• T1: ControlwithoutSandKfertilization (100% NP through urea and DAP only) • T2: 100%NPK(urea,DAP,MuriateofPotash(MOP))• T3: 100%NP+50%SthroughPolysulphate(20kgSha-1) (balanced K through MOP to make 100% K)• T4: 100%NP+75%SthroughPolysulphate(30kgSha-1) (balanced K through MOP to make 100% K)• T5: 100%NP+100%SthroughPolysulphate(40kgSha-1) (balanced K through MOP to make 100% K)• T6: 100%NPK(urea,DAP,MOP)+100%Sthroughgypsum (40 kg S ha-1)

The recommended dose of fertilizers:120kgN,60kgP2O5,60kgK2O ha–1 and 40 kg S ha–1wasappliedasperthetreatments.FulldoseofP,K,SandhalfdoseofNwereappliedatthetimeofsowingasabasalapplication.TheremaininghalfdoseofNwasappliedintwoequalsplits,atthestagesofmaximumtilleringandflowerinitiation.

Results• Sesameyieldincreasedsignificantlyandsteadilyinresponseto

theincreasingSdoseappliedthroughPolysulphate(T3-T5).• Seedyieldincreasedby33%atthemaximumSdoseof40kgSha-1

(T5)whencomparedtonoSaddition(T2).ThesameSdose,whenappliedthroughgypsum(T6),yieldedslightlyfewerseeds.

• TheresponseofoilyieldtoPolysulphateapplicationwasdramatic,providing43%increase(T5vs.T2).Sulphurappliedthroughgypsum(T6)alsogaverisetoasignificantincreaseinoilyields,althoughtoalesserextentthanwithPolysulphate.

• Yieldcomponentslikepodsperplant,podlength,seedsperpodandseedweightwerehighestatthemaximumSlevel(T5).

• KandSuptakebysesamecropincreasedwithincreasingSdoseappliedthroughPolysulphate(T3-T5).

Treatments

Seed

yie

ld (t

/ha)

1.5

2.0

2.5

1.0

0.5

0.0

1.0

0.8

0.5

1.3

0.0

0.3 Stov

er y

ield

(t/h

a)

Seed Stover

T1NP

T2NPK

T3NPKS20

Polysulphate

T4NPKS30

Polysulphate

T5NPKS40

Polysulphate

T6NPKS40

Gypsum

+33%increase

(comparedto T2)

WhenSowing:July2014Harvest:October 2014

WhereKanpur,UttarPradesh,India

CropSesame (Sesamum indicum L.)

Soil typeSandy loam

Measurements• Yield • Yield components • Oil content• Nutrient uptake

60


®

Trial

SoybeanBrazil

ObjectiveEvaluatetheeffectofPolysulphateasasourceofsulphurforsoybeaninBrazil’sCerradoregion.

TreatmentsThis randomized block trial consisted of six treatments and fourreplications.ThetreatmentswerecombinationsofMAP,KCl,Polysulphate,singlesuperphosphateandpastilledelemental sulphur (S) to supply 80 kg/ha P2O5,80kg/haK2O and25kg/haofS,exceptinthecontroltreatmentwherenoSwasapplied.MAPandsinglesuperphosphatewereappliedinfurrow;KClwasbroadcastbeforeplanting;Polysulphateandelementalsulphurwereappliedbothinfurrowandbroadcastbefore planting according to each treatment.

Results• Polysulphate is a highly viable source of sulphur for soybean fertilization.• Polysulphate fertilizer increased soybean yield by 16%

comparedwithfertilizationwithoutsulphur.• Using Polysulphate as the source of sulphur

increased soybeanyieldby9.6%comparedwithsinglesuperphosphate.

• Ayieldimprovementof14%wasrecordedwithPolysulphatecomparedwithpastilledelementalsulphur.

Yiel

d (t/

ha) 3.5

4.0

3.0

2.5

All treatments were fertilized with 80 kg/ha of P2O5 and 80 kg/ha of K2O applied as MAP in the furrow, and 80 kg/ha of K2O applied as KCl in broadcast. Sulphur treatments had a dose of 25 kg S/ha.



Control

b

Singlesuperphosphate

(furrow)

ab

Elemental S(broadcast)

ab

Elemental S(furrow)

b

Polysulphate(broadcast)

ab

Polysulphate(furrow)

a

+9.6%yield increase

compared with single

superphosphate

WhenSowing:October2016Harvest:February 2017

WhereLucasdoRioVerde,MatoGrossostate,Brazil

CropSoybean (Glycine max)

Soil typeClay soil (Oxisol)

MeasurementsYield

61


®

Trial

SoybeanArgentina






Soyb

ean

grai

n yi

eld

kg/h

a

2,000

2,500

3,000

3,500

1,000

1,500

500

0

dcd

c

b

aba

Control (S=0)

SSP (S=19)

MAP+Gypsum (S=19)




When2016/17

WhereMercedes,Corrientes,Argentina



MeasurementsYield

Results• Soybeanrespondedsignificantlytosulphurapplication• TherewerestatisticaldifferencesbetweenthePolysulphate

andothersourcesofsulphur.Additionally,thesoybeanresponded to increasing rates of Polysulphate as a result of agrowingnutrientaddition.

+61%yield increaseas compared

to control

62


®

Trial

SoybeanBrazil

ObjectiveToevaluatetheagronomicefficiencyofPolysulphateandPotashpluS as a sulphur source on the yield of soybean.

TreatmentsThisrandomizedblocktrialconsistedofsixtreatmentswithfourreplications.TreatmentswerecombinationsofMAP,MOP,Polysulphate,PotashpluS,singlesuperphosphate,pastilledelementalSandonecommercialblendwithMAPandsulphurintwoforms,sulphateandelemental.Alltreatmentswerefertilizedwith80kg/haP2O5 ,80kg/haK2O and 20 kg/haS,exceptthecontroltreatmentwhereSwasnotapplied.TheMAP,singlesuperphosphate,MAP+S,PolysulphateandpastilledelementalSwereappliedinthefurrow;MOPandPotashpluSwereappliedbroadcastandpre-planting.

Results•PolysulphateinthefurrowandPotashpluSinbroadcastwere

highly viable sources of sulphur for soybean fertilization.•Soybeanyieldincreasedover3.9%incomparisontothefertilizationwithoutsulphur.

• Incomparisonwithothersulphursources,ICLproductsincreasedsoybeanyieldby1.5to3.5%.

All treatments were fertilized with 80 kg/ha P2O5 , 80 kg/ha K2O and 20 kg/ha S, except control treatment where sulphur was not applied. Sulphur sources

t/ha

4.53

4.59

4.56

4.62

4.65

4.68

4.71

4.74

4.77

4.80

4.83

Single super-phosphate

Pastilled elemental S

MAP+S PotashpluS PolysulphateNo S

WhenPlanting:November 2018Harvest: March 2019

WhereCruzAlta,RioGrandedoSulstate,Brazil


Soil typeClay oxisol

MeasurementsYield

+3.8%yield

increase

63

®

Trial

SoybeanParaguay

Different letters above bars indicate signifi-cant differences among treatments (P<0.05)


ObjectiveTocomparetheagronomicefficiencyofbulkfertilizerblendsthatincludePolysulphatewithotherformulationscurrentlyinuse,forsoybean crop in Paraguay.

TreatmentsThefivetreatmentsconsistedoftwocommonfertilizerblends(5-20-10and5-30-15)havingdifferentproportionsofP2O5:K2O (2:1and3:1)andwerepreparedusingMAP,SSP,andaKsource(KClorPolysulphate).Thefourgradeswerecomparedwithmono-ammonium-phosphate(MAP)asacontrollackingS,KandMg.Allfivetreatmentsreceivedthesamerateof70kgP2O5 ha–1.

Treatment(fertilizer blend)

P2O5 :K2O

GradeNPKS

Fertilizer rate N P2O5 K2O MgO S

kg ha-1

T1 Control - MAP - 10-52-0-0 S 135 15 70 - - -T2 MAP,SSP,KCl 3:1 5-30-10-5S 233 11 70 23 - 11T3 MAP,SSP

Polysulphate3:1 6-30-10-6S 233 15 70 23 5 15

T4 MAP,SSP,KCl 2:1 5-30-10-5S 233 12 70 35 - 8T5 MAP,SSP

Polysulphate2:1 6-30-10-6S 233 15 70 35 3 10

Results• Soybeancropshowedsignificantyieldincreaseinresponseto

Polysulphate application at both K2Odoses:6.8%and10.8%whencomparedwiththecontroltreatment,for23kgK2O/haand35kgK2O/ha respectively.

• TheuseofPolysulphatesignificantlyincreasedsoybeanyieldby5.3%(T3:23kgK2O/ha,3:1P:Kratio)whencomparedwithKClasKsource(T2);buttherewasnoadvantagetoeitherKClnortoPolysulphate at the higher K2O dose (2:1 P:K ratio).

Soyb

ean

yiel

d (t/

ha)

Treatments

4.4

4.2

3.8

3.6

3.4

4.0

3.0

3.2

T1Comtrol

(MAP)

c

T2MAP+SSP+KCl

K23

c

T3MAP+SSP

+PolysulphateK23

b

T4MAP+SSP

+KClK35

a

T5MAP+SSP

+PolysulphateK35

a

+10.8%yield

increase

WhenSowing:October 2017Harvest: March 2018

WhereItapúa,Paraguay


Soil typeUltisol

MeasurementsYield

64


®

Trial

StrawberryColombia

ObjectiveToevaluatetheeffectonstrawberryyieldofusingPolysulphate as a complementary nutrient source.

TreatmentsThistrialconsistedoftwelve35mbeds,eachwith210plants.Fourtreatments,orPolysulphatedoses,wereappliedonaoneyearoldplantation:1)NoPolysulphate,2)5g/plant(250kg/ha),3)10g/plant(500kg/ha),4)15g/plant(750kg/ha).AlltreatmentsreceivedatotalNPKapplicationof200,140and280kg/ha,fromurea,Enraifos,potassiumsulphate,kieseriteandincludedPolysulphateasacomplementaryK,CaandMgsource.Alltreatmentswerealsofertigatedeveryweekusingafarmer’scombinationofallnutrients.

Results• Polysulphatehadapositiveeffectonstrawberryyield.• Polysulphateincreasedyieldupto95%comparedwiththe

controlwithoutPolysulphate.• SupplyofK,Ca,MgandSfromPolysulphateimprovedthe

fruitsetting,appearanceandshelflife.• ArecommendedPolysulphatedoseof10g/planttwiceor

threetimesayearincreasesstrawberryproductivityandimproves fruit quality.


8 W

eeks

Yie

ld (k

g/ha

)

14,000

12,000

10,000

8,000

6,000

4,000

2,000

0

Polysulphate dose (g/plant)

0

b

5

b

10

a

15

b

+95%yield

increase

WhenPlanting:September 2017Harvest: April 2018 to March 2019

WhereSotara,CaucaState,Colombia

CropStrawberry(Fragaria X ananassa Duch.,cvSabrina)

Soil typeAndisol,SiltloamwithacidicpH(5.6),highOM(26.3%)andmediumK,Ca,Mgcontents

MeasurementsTotal yield during twomonthsoftheharvest peak

65

®

Trial

StrawberryChina

ObjectiveToevaluatetheeffectofreplacingtheKsuppliedbythefarmerspracticewithPolysulphateontheyieldandqualityparametersofstrawberrycropgrowninHubeiProvince,China.

TreatmentsFarmer practice: 525 kg/ha compound fertilizer (N: P2O5: K2O 12:12:17).

Equal replacement (100% K from Polysulphate): K from Polysulphate used to replace 100% K in compound fertilizer used by farmers. N from urea and P from DAP.

125% K from Polysulphate:125%KfromPolysulphatewasused. N from urea and P from DAP.

Alltreatmentsreceived375kg/haofcalciumsuperphosphateatseedling;500kg/haoforganicfertilizerintop-dressing,threetofivetimes;75kg/haofAmericanJiabao(22%K2O)+75kg/haUltrasol (15% K2O) during fruit period.

Results

Total acidity

Soluble solid (%)

Sugar-acid ratio

Flavor

Average weight per fruit (g)

Average weight per plant

Farmer practice 3.26b 6.17 c 1.89 b Sweet

and sour 29.12 b 56 c

100% K from Polysulphate 3.42a 6.57 b 1.92 b Sweet

and sour 31.02b 60 b

125% K from Polysulphate 3.44a 7.17 a 2.08 a Sweet 35.22a 63a

ConclusionsWhen adding the same amount of K through Polysulphate comparedwithcompoundfertilizer,thereisasignificantincreaseinthetotalacidity,fruitsolublesolids,flavor,averageweightperfruit,numberoffruitperplantandyield.Thistrendstrengthenswhenaddinganadditional25%ofKthroughPolysulphate.


Research PartnerWuhan Academy of Agriculture Science, Huangpi district, cooperation with AMPC Zhejiang.

Yiel

d - t

/ha

100% K from Polysulphate

b

125% K from Polysulphate

a

202530

1015

50

c

Farmer practice

+3.56%yield

increase

+6.5%yield

increase

WhenSowing:6 September 2016Harvest:5 December 2016

WhereWuhan,Hubeiprovince,China

CropStrawberry (Fragaria ananassa)

Soil typeCalcareous alluvial soil

Measurements• Fruitweight• Fruit quality• Yield

66

®

Trial

Sugarcane USA

ObjectiveTo evaluate Polysulphate as a K fertilizer source for sugarcane growninsandy,silt-loamsoilsinsouthernLouisiana,USA.

TreatmentsGrowerstandardpracticeconsistedof135kgN/haintheformofurea,45kgP2O5/haintheformofDAPand135kgK2O/ha intheformofKCl.ThereweretwoPolysulphatetreatmentswhichwereduplicatesofthegrowerstandardpractice,butwiththeKportionbeingmadeupof50:50Polysulphate&KCl,or 100% Polysulphate.

Results• Supplying 50% of the K dose as Polysulphate increased

the sugarcane yield by 504 kg/ha (4.5%) over conventional growerstandardpractice.

7

8

9

10

11

12

Suga

r yie

ld (t

on/h

a)

GrowerstandardpracticeUrea+DAP+KCl

135N-45P2O5-135K2O kg/ha

100% K from PolysulphateUrea+DAP+Polysulphate135N-45P2O5-135K2O

185 S - 58 MgO - 164 CaO kg/ha

14

13

50% K from KCl and 50% K from Polysulphate

Urea+DAP+KCl+Polysulphate135N-45P2O5-135K2O

92 S - 18 MgO - 81 CaO kg/ha

WhenPlanting:Second ratoonHarvest:October,2018

WhereUSDA ARS Sugarcane Research UnitWhiteCastle,Louisiana,USA

CropSugarcane (Saccharum officinarum)

Soil typeSandy,silt-loamsoil

MeasurementsSugar yield

+4.5%yield

increase

67

®

Trial

Sugarcane Colombia

ObjectiveToevaluatetheeffectonsugarcaneofusingPolysulphateasacomplementarynutrientsource,inparticularitseffectonbiomass at the seedling stage.

TreatmentsThistrialconsistedoffivetreatments:twocontrolsandthreePolysulphatedoses(0,1.5,3and6g/plant)applied5daysafterplanting.1)8gof16-7-13,2)1.5gofPolysulphate,3)3gofPolysulphate,4)6gofPolysulphate,5)Amixtureofsoil and compost (1:1). Treatments 1-4 received a total NPK applicationof1.3,0.6and1.1g/plantfromurea,DAPandusingPolysulphate as a complementary K source reducing the KCl applied.

Results• Polysulphatehadapositiveeffectonsugarcaneseedling

growthatallapplicationratesupto6g/plant.

• Polysulphatesignificantlyincreasedshootbiomass,doublingit,whencomparedwiththetwocontrolswithoutPolysulphate.

• SupplyofK,Ca,MgandSfromPolysulphatereducedrootbiomass.

• PlantsfertilizedwithPolysulphatehadaroot:shootratiohalfthatofthecontrols,indicatingbetterbiomasspartitioning in sugarcane seedlings.

• Arecommendeddoseof200-300kg/haofPolysulphatefortheCaucarivervalleywouldimproveshootbiomassandsugarcane productivity.


Biom

ass

(g/p

lant

)

Root

: Sh

oot r

atio

100

90

80

70

60

50

40

30

20

10

0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Treatment (g/plant)

Soil:M (1:1)(16-7-13)8 Polysulphate 6Polysulphate3Polysulphate 1.5

RootShootR:S

a

b b b

ab

WhenPlanting:September 2018Harvest:January2019

WhereBalboa,RisaraldaState,Colombia

CropSugarcane (Saccha-rum officinarum), var. CC01-1940 at seedling stage

Soil typeVertisol,sandyloamwithacidicpH(6.2);lowOM(2.5%);andhigh Ca and Mg content

Measurements• Shoot and root

biomass• Root: shoot ratio

68

®

Trial

TeaVietnam

ObjectivePolysulphatewasexaminedasapotentialadditivetocompoundNPKfertilizers,aspartofanalternativefertilizationprogramforthetea industry in the Lam Dong district.

TreatmentsThreefertilizertreatmentsweretestedattwositesofsevenyearoldteaplantationsoftwovarietiesoftea(KimTuyenandTB14)betweenAprilandDecember2015.Thefirsttreatment(CT1)wasfarmers'standardfertilizerpractice,thesecondtreatment(CT2)usedlocallyavailable commercial compound fertilizer and the third treatment (CT3)wasthesameasCT2butfortifiedwithPolysulphate.

Fertilizer

Bao Loc (cv. Kim Tuyén) Bao Lam (cv. TB14)

CT1 (Control)

CT2 (Phu My

Fertilizer)

CT3 (Phu My Fertilizer +

Polysulphate)

CT1 (Control)

CT2 (Phu My

Fertilizer)

CT3 (Phu My Fertilizer +

Polysulphate)Amount of fertilizer (kg ha-1)

Polysulphate 0 0 200 0 0 150NPKS (16-16-8-13) 0 800 800 0 400 400

NPK (15-15-15) 0 1,000 1,000 0 500 500

NPK (25-9-9) 0 1,500 1,500 0 750 750NPK (27-6-6) 0 1,500 1,500 0 750 750Urea 3,200 900 900 1,600 450 450Fused Ca-Mg-P 3,353 0 0 1,677 0 0

KCl 832 100 53 466 100 65

ResultsPolysulphate,addedtoasystematicNPKfertilizationprogramforteaplantsgrownonreddishbrownsoilinLamDong,Vietnam,enhancedthedensity,weightandsizeofteabuds,thusincreasingteaproductivityofbothvarietiesofteaby14.1-15.3%.Polysulphatealso improved tea quality parameters such as dry matter content andtheconcentrationsofsolublesubstances,tanninsandcaffeine,whichareimportantforflavorintea.

ConclusionsPolysulphate enhances the volume and quality of tea buds. Overall,Polysulphateincreasedfarmers'profitbyupto13%.Forbothcultivars,CT2wassignificantlymoreprofitablethanCT1,andCT3morethanCT2.Theseresultssuggestthatthecommontea fertilization practice (CT1) in these regions of Vietnam may be considerably improved by using Polysuphate.

CT3

Rela

tive

tea

bud

yiel

d (%

)

TreatmentCT2CT1

120

115

110

100

95

90

CultivarKim TuyenTB14

WhenSowing:8May2016Harvest:3July2016

WhereLamDongdistrict,Vietnam

CropTea (Camillia sinensis)


Measurements• Bud density• Budweight• Bud length• Tea bud yield• Tea quality

parameters

Research PartnerPetrovietnam Fertilizer and Chemicals Corporation (PVFCCo), Vietnam.

+14.1%increase

+15.3%increase

69

®

Trial

TomatoChina

ObjectiveTo evaluate the addition of Polysulphate and sulphate of potash(SOP)tothefarmers’practiceontheyieldandyieldparametersoftomatocropgrowninHenanProvince,China.

TreatmentsThis randomized complete block trial consisted of three replicateswiththreetreatments.1)Farmerpractice,2)Farmerpractice+750kg/haofSOP,and3)Farmerpractice+750kg/ha of Polysulphate.

Farmer practice consisted of applying 7.5 ton/ha organic fertilizerasbase-fertilizer.Inaddition,therewere4topdressingsof240kg/haofureaduringthewholegrowthperiod.

Different letters above bars indicate significant differences among treatments(P <0.05)

65

60

55

50

70

75

80

85

90

Tom

ato

yiel

d (to

n/ha

)

Farmer practice Farmerpractice+PolysulphateFarmerpractice+SOP

a

bc

Results• Polysulphate application led to an increase in the number of

fruitsperplant,andanincreaseinfruitweight.• ComparedwithSOPapplication,theaverageyieldinthe

treatmentwithPolysulphateincreasedby8.84ton/ha(yieldincrease of 11.6%).

• Polysulphateapplicationsignificantlyincreasedyieldsascomparedwithfarmerpractice:theaverageyieldwhentreatedwithPolysulphateincreasedby14%.

WhenPlanting: April 2016Harvest:July2016

WhereZhoukou,Henanprovince,China

CropTomato (Solanum lycopersicum),varietyNO.4 Zhengfen

Soil typeFluvisol(fluvo-aquicsoil)

Measurements• Yield• Number of fruits

per plant• Fruitweight

+14% yield increaseas compared with farmer

practice

70

®

Trial

TomatoChina Objective

To evaluate the addition of Polysulphate and sulphate of potash(SOP)tothefarmers’practiceontheyieldandyieldparametersoftomatocropgrowninHenanProvince,China

TreatmentsThis randomized complete block trial consisted of three replicateswiththreetreatments.1)Farmerpractice,2)Farmerpractice+750kg/haofSOP,and3)Farmerpractice+750kg/ha of Polysulphate.

Farmer practice consisted of applying 7.5 ton/ha organic fertilizerasbase-fertilizer.Inaddition,therewere4topdressingsduringthewholegrowthperiod.Eachtopdressing consisted of 75 kg/ha urea and 150 kg/ha compound fertilizer (15-15-15).

Results• Polysulphate application led to an increase in the number of

fruitsperplant,andanincreaseinfruitweight.• ComparedwithSOPapplication,theaverageyieldinthe

treatmentwithPolysulphateincreasedby4.88ton/ha(yieldincrease of 5.9%).

• Polysulphateadditionsignificantlyincreasedyieldsascomparedwithfarmerpractice:theaverageyieldwhentreatedwithPolysulphateincreasedby8.8%.

Different letters above bars indicate signifi-cant differences among treatments (P <0.05)

65

60

55

50

70

75

80

85

90

Tom

ato

yiel

d (to

n/ha

)

Farmer practice Farmerpractice+PolysulphateFarmerpractice+SOP

a

bc

WhenPlanting: March 2016Harvest:June2016

WhereShangqiu,Henanprovince,China

CropTomato (Solanum lycopersicum),varietyNO.4 Zhengfen

Soil typeSandy,fluvisol(fluvo-aquic soil)

Measurements• Yield• Number of fruits

per plant• Fruitweight

+8.9% yield increaseas compared with farmer

practice

71

®

Trial

TomatoColombia

ObjectiveToevaluatetheeffectontomatoyieldofusingPolysulphateasa complementary nutrient source.

TreatmentsThistrialconsistedofsixrowswithtwotreatments:1)NoPolysulphate,2)60gofPolysulphate/plant,equivalentto1.5tons/ha,applied46daysafterplanting.BothtreatmentsreceivedatotalNPKapplicationof200,200and400kg/ha,from10-30-10,10-20-20,16-16-16.Treatment2usedPolysulphate as a complementary K source that reduced the KClapplication.Thewholecropreceivedsoilfertilizationat10,46,55and85daysafterplanting,plusfertigationeverytwoweeks.

Results• Polysulphateincreasedtomatoyieldby5%comparedwith

the control.• AdditionofK,Ca,MgandSfromPolysulphateimprovedthe

fruit setting and appearance.• Polysulphate application resulted in a high reduction of

blossom-endrot,commonintheregion.• Adoseof30-60g/plantofPolysulphateisrecommendedto

increase tomato productivity and improve fruit quality.

Bars indicate standard errors.

Accu

mul

ated

yie

ld (t

/ha)

120

115

110

105

100

95

90

Treatment (g/plant)

Control 60g Polysulphate

+5%yield

increase

WhenPlanting:August 2018Harvest:November 2018

WherePopayán,CaucaState,Colombia

CropTomato (Solanum lycopersicum) hybrid Ichiban

Soil typeAndisol,siltloamwithacidicpH(5.3),high OM (15.9%) and mediumK,Ca,andMg content

MeasurementsTotal yield

72

®

Trial

Winter wheatUK Objective

ToinvestigatetheeffectofPolysulphatefertiliserasanautumnapplicationtowinterwheat.Specifically,toincreaseyieldthroughcrop establishment.

WithUKsoilsbeingloworcriticalforsulphurdepositsandplantsneedingStotakeupnitrogen,thisexperimentisdesignedtotestwhetherPolysulphateimprovesresidualnitrogenuptakebytheplant and improves establishment of the crop.

TreatmentsThebasefertiliser(0-20-30)wasappliedat250kg/ha.Thefieldwassplitdownthemiddle.

ResultsBelowyoucanseethedifferenceinyieldbetweenthecontrolandtheareatreatedwithPolysulphate,ayieldimprovementof354kg/ha.

ConclusionInthistrialwefoundthatPolysulphateimprovedtheoverallyieldby354kg/ha.Theaveragepriceforgrainwas£170/t(accordingtothefarmer),whichmeansthatPolysulphatefertiliserimprovedthereturnforthefarmby£60.18perha.

Whenweremovethecostsofthe100kgoffertiliser(£16)perhectare,thereturnoninvestmentinthistrialis£44.18/ha.

Field A - 1.92 ha Field B - 1.92 ha

250kg/ha0-20-30basefertiliser100 kg/ha Polysulphate

250kg/ha0-20-30basefertiliser

When2018

WhereUK

CropWinterwheat(Triticum aestivum)


MeasurementsYield

6.8

6.6

6.4

6.3Control

7.0

6.9

6.7

6.5

Polysulphate

Yiel

d - t

/ha

+5.4%yield

increase

73

®

Trial

WheatArgentina




The crop received 75 kg N ha–1,appliedpriortoemergenceinthe form of urea.

Results• Theresponsetosulphurwasconclusive,givingthestatistical

differencebetweenthecheckandtheothertreatments.• Quality parameters like protein and gluten content also

responded to S.• Althoughnotstatisticallysignificant,apositiveresponseto

growingratesofPolysulphatewerenoted.

Prot

ein-

kg/

ha

450

500

550

600

400



Gra

in y

ield

- kg/

ha

b

a a a a

4,000

5,000

6,000

7,000

2,000

3,000

1,000

0

a

Control (S=0)

SSP (S=19)

MAP+Gypsum (S=19)




Control (S=0)

SSP (S=19)

MAP+Gypsum (S=19)




When2016

WhereNuevedeJulio,Argentina

CropWheat(Triticum aestivum)


Measurements• Grain yield• Protein yield

+34.5%yield increase


74


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Field trials - Polysulphate

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