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Controlled Release FertilizersControlled Release FertilizersAvi Shaviv

Faculty of Civil & Environmental Engineering Technion-IIT, Haifa, Israel.

agshavivagshaviv@@txtx..techniontechnion.ac..ac.ilil

IFA International Workshop: Enhanced-Efficiency Fertilizers27-30 June 2005, Frankfurt, Germany

CRFCRF’’s s -- ““High Agronomic Use Efficiency High Agronomic Use Efficiency while minimizing Environmnetal Impact ,,, in while minimizing Environmnetal Impact ,,, in one single applicationone single application””

Conventional fertilization goes with high N (and Conventional fertilization goes with high N (and other) losses to GW (NOother) losses to GW (NO33) and to air (NH) and to air (NH33, N, N22O ,,O ,,NoNoxx))

Great efforts to develop approaches, techniques Great efforts to develop approaches, techniques and Fertilizers to minimize damage and sustain and Fertilizers to minimize damage and sustain agriculture (soil, water, production potential)agriculture (soil, water, production potential)

Increasing awareness to fertilizer impact onIncreasing awareness to fertilizer impact onEnvironment

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Pathways of Loss

Plant Uptake Plant Uptake --

NN--PP--K and MeK and Me

Microbial Reactions

SYNCRONISYNCRONI‎‎ZAZA‎‎TIONTION-- ..Plant Demand ..Plant Demand vs. Nutrients Supplyvs. Nutrients Supply

SUPPLY: Preferred & BioSUPPLY: Preferred & Bio--Available Available Nutrient CompositionsNutrient Compositions ammonium/nitrate; ammonium/nitrate;

NHNH44+ + /P/P

NHNH44+ + or K / Microelementsor K / Microelements

3

Improve Application MethodsImprove Application Methodsor or Modify FertilizersModify Fertilizers

•• Positioning: Banding, nesting,,, Super Granules (high NH4 conc. To reduce nitrification)

• Bio-Inhibitor Amendments (NI’s)

• Controlled Release Fertilizers•Targeted Delivery Fertigation, Precision Agriculture

CRF vs. SRFCRF vs. SRF

SRF SRF UF, MEU, SCU, PSCU?UF, MEU, SCU, PSCU?

CRFCRF Polymer coatedPolymer coatedOne single application,,, provides prolonged One single application,,, provides prolonged

supply of nutrientssupply of nutrients

Matches (better) plant demandMatches (better) plant demand……(level, proportions, timing)

The closer the synchrony

higher NUENUE and lower LOSSESLOSSES

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CRF vs. SRFCRF vs. SRF Release Release less sensitive to:less sensitive to:Soil/medium type, moisture, pH, Soil/medium type, moisture, pH,

microbial activitymicrobial activity MinimizesMinimizes: : losses to environment, losses to environment, application cost, application cost, stress on plants,stress on plants, EnsuresEnsures: : --

better growth & yields, better growth & yields, high quality food/producthigh quality food/product

,,,,,,,,,,,,,,,,,,,,,,,,,YET ,,,,,,,,,,,,,,,,,,,,,,,,,YET -- CRF COST is A LIMITCRF COST is A LIMIT

Nutrient coreNutrient core

Polymer coatingPolymer coating

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water vapordissolution

rupturerupture ((““failurefailure””))immediate releaseimmediate release

diffusion / convectiongradual release

swelling

PP

r

rrllPPSS

PPhh

Coatings: Coatings: Alkyd Type, Alkyd Type,

PolyPoly--Urethane like, Urethane like,

PolyPoly--Olefin (modified), Olefin (modified),

Poly Poly ––Sulfur Coated (??), Latex? Sulfur Coated (??), Latex?

Release Affected byRelease Affected by:

PermeabilityPermeability TT, Solubility ?!

RadiusRadius r,r,

Coating thickness – l,l,

Slightly affected bySlightly affected by water water content, pH, medium typecontent, pH, medium type

Rel

ease

Rel

ease

TimeTime

lagDiffusion

Failure

linearrelease

decay

Release from a Single Coated Urea Release from a Single Coated Urea Granule: Granule: Diffusion Diffusion vsvs FailureFailure

6

0

40

80

0 50 100 150 200

Time (days) %

R

elea

seP3�

hPlrt

*','C3),,( sat tttttlrPtlrg

s

s

laglag

linearlinear

*

3exp

C1),,(

s

sat ttlrP

tlrg s

decaydecay

Shaviv et al, 2003a,b, Envir. Sci & Tech, Model of Urea (or single fertilizer) ReleaseModel of Urea (or single fertilizer) Release

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140

time [day]

rele

ase

exp. calculated

Modified Poly-Olefine

Exp vs Model for for Population of granulesPopulation of granules

7

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140

time [day]

rele

ase

exp. calculated

Poly-Urethane Like

Exp vs Model –– for for Population of granulesPopulation of granules

R l in e a r ~ C s a t x P S = C s a t0 e x p ( -E A C /R T ) x P S

0 e x p ( -E A P s /R T )

R l in e a r ~ C s a t0 x P S

0 e x p [- (E A C + E A P s) / R T ]

L o g R l i n e a r v s 1 /R T E A = E A C + E A P s

Energy of Activation for Release helps Energy of Activation for Release helps in Modeling Temperature effectin Modeling Temperature effect

or,,,,,, the concept of the concept of Cumulative Rate of N releaseCumulative Rate of N release(Gandeza et al., 1991)

CRN = a + b (CT) + c (CT)2

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Important Release FeaturesImportant Release Features

•• Pattern:Pattern:

•• FickianFickian (parabolic), linear, (parabolic), linear, sigmoidalsigmoidal, , bibi--modalmodal

•• Duration:Duration:

Time of releaseTime of release of content (of content (75%, 80%?)75%, 80%?)

at given temperature, 21at given temperature, 2100C or 25C or 2500C (?)C (?)

•• Burst Burst (initial release < few %)(initial release < few %)

•• Tailing Tailing -- LockoffLockoff (non (non utilisedutilised nutrient)nutrient)

Cumulative Urea Release

0

40

80

0 50 100 150 200Time (days)

%

Rel

ease

Alkyd type PSCU Polyolefin Polyurethane

Burst

Lock-off / tailing

SigmoidalFickianFickian

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CRU N - BALANACE

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180

TIME (DA YS)

N BA

LANC

E %

N R EC O VE R Y N U PTAKE INCUBATION

Release Prediction Important for Better Release Prediction Important for Better Synchronizing Plant Demand with Nutrient Synchronizing Plant Demand with Nutrient

SupplySupply

ReleaseRelease

Note Note –– SigmoidalSigmoidal PatternPattern

time , daystime , days

Cum

ula t

ive

Cu m

ula t

ive

Re l

eas e

Re l

eas e

Practically – release from large population => high variation – Ph, Ps, l, r, Statistics Statistics

50

10

long term release ,NO 3, 6C

020406080

100

0 50 100 150 200 250time ( days )

%

NO3

rele

ase

Osmocot Pluss 329

Osmocot Pluss 330

Osmocot Pluss 331

Plantacote Pluss 338

Nutricote 349

NPK 12-300

NPK 12-1998

long term release ,NO3, 21 C

02040

6080

100120

0 50 100 150 200 250time (days )%

N

O3

rele

ase

Osmocot Pluss 329

Osmocot Pluss 330Osmocot Pluss 331Plantacote Pluss 338

Nutricote 349

NPK 12-300NPK 12-1998

` balance

long term release ,NO 3 , 30 C

020406080

100120

0 50 100 150 200

time (days)

%

NO

3 re

leas

e

Osmocot Pluss 329

Osmocot Pluss 330

Osmocot Pluss 331

Plantacote Pluss 338

Nutricote 349

NPK 12-300

NPK 12-1998

Temperature Temperature EffectEffect

Various Various CRFsCRFs

~ 1.5 ~ 1.5 ––2.0 increase2.0 increase

for 10for 1000CC

0

10

20

30

40

50

60

70

80

90

0 50 100 150

% N

-NH

4re

leas

e

time (days)

8oC 21oC 30oC 40oC

~ 1.5 ~ 1.5 ––2.0 fold increase for each 102.0 fold increase for each 1000CC

~ ? ~ Q10 factor~ ? ~ Q10 factor

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Effect of soil/medium properties Effect of soil/medium properties (or water status?)(or water status?)

% r

elea

se

0

10

20

30

40

50

60

70

80

90

100

7 days 49 days 101 days

Sand

Peat pH 4.5

Limed peat

Water

Release at 30oC

Release only SLIGLTY affected by soil type and soil pH

Effect of dryingEffect of drying--wetting cycles (=irrigation)wetting cycles (=irrigation)

0

5

10

15

20

25

30

35

40

45

50

7 days 28 days 35 days 49 days

% r

elea

se

Dry&Wet

Control

• Important Important -Drying-wetting cycles do not damage the coating• TThe release is slowed down when the soil is dry he release is slowed down when the soil is dry ––(this prevents salt accumulation and root scorching)

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Release from a compound CRF Release from a compound CRF

more complicatedmore complicated•Different Solubilities of NONO33 , NH, NH44 , P , K, P , K

•Limited amount of WATER for dissolution

•Moisture content Changes:

Free Water,

Saturated Soil

Unsaturated Soil

•Temperature Changes

Rrelease, NO3, 30C

0

20

40

60

80

100

120

0 50 100 150 200time (days)

%

NO

3 re

leas

e Osmocot Pluss 327

Plantacote Pluss 335

Nutricote 347

AGROBE len 351

NPK 8-300

NPK 8-31

Release , P, 30C

0

20

40

60

80

100

0 50 100 150 200time (days)

%

P re

leas

e

Osmocot Pluss 327

Plantacote Pluss 335

Nutricote 347

AGROBE len 351

NPK 8-300

NPK 8-31

DifferentDifferent

Release Release Patterns/Patterns/

RateRate

Typical Typical

For All For All single single FertsFerts. . basis basis CRFsCRFs

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Release F1 - free water (20 C)

0

20

40

60

80

0 20 40 60 80

day

Rel

ease

(%)

K

NO3

NH4

P

Release F1 - free water (40C)

0

50

100

0 20 40 60 80

Day

Rel

ease

e (%

)

KNO3NH4P

NONO3 3 ~ NH~ NH4 4 > K > P> K > P

Characteristic Coated CRF – limitedlimited water amount in granulegranule

•• Characterization,,,,,,,,,,,,Characterization,,,,,,,,,,,,

•• Testing,,,,,,,,,,,,Testing,,,,,,,,,,,,

•• Performance EvaluationPerformance Evaluation

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15

Experiments in Different Planting Systems

• Pots, low volume

• Containers (detached media), 30 Liter

• Lysimeters , 130 liter (to mimic field conditions ,,,ACAP)

• Real soil experiments, complicated/difficult when Mass Balance & Environmnetal Impact needed

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Ryegrass Experiment – to test the effect of

Urea ReleaseUrea Release Pattern on Growth and Leaching

4 cuttings (each 4-5 weeks)

Leaching before each cutting

CRFs –

Three N levels 0.8, 1.2, 1.6 gN/pot

Special CRU 932; CRU 948; CRU 1049 with different SIGMOIDAL N release patterns and Durations

PSCU – Polymer sulphur Coated Urea - with “burst” and “lockoff”

Compared to urea application : 1/3 at start (solid) 1/3 after 1st harvest (liquid); 1/3 after 2nd harvest,

PSCU

932

948

PSCU

35d80d

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CRF vs. SRF CRF vs. SRF Ryegrass in pots, 4 cuttings & Ryegrass in pots, 4 cuttings & leachingsleachings

CRU N - BALANACE

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180

TIME ( DAYS )

N B

ALA

NC

E

N RECOVERY N UPTAKE INCUBATION

PSCU N - BALANCE

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180

TIME ( DAYS )

N BA

LANA

CE

N RECOVERY N UPTAKE INCUBATION

ShavivShaviv, 1966, 1966

Synchronizing Urea Supply with plant demand resulted in Synchronizing Urea Supply with plant demand resulted in maximal DM yield and Minimal N losses, No Damage to maximal DM yield and Minimal N losses, No Damage to

PlantsPlants

CRU CRU 80 d80 d

CRU CRU 35 d35 d

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Container Experiments:Container Experiments:Volcanic Tuff Volcanic Tuff -- 1999, 1999, PerlitePerlite -- 20002000

Red Volcanic Tuff, 0Red Volcanic Tuff, 0--8 mm (porous)8 mm (porous)CEC 15 CEC 15 meqmeq/100g, /100g, Qsat Qsat 50%50%(Amorphous Clay, Volcanic Glass, Primary Min., Iron (Amorphous Clay, Volcanic Glass, Primary Min., Iron Min.)Min.)PerlitePerlite, 2, 2--3mm (porous)3mm (porous)low CEC, low CEC, QsatQsat 65%65%

Basil Basil -- 4 4 Harvestes Harvestes (30 days)(30 days)33--5 5 fertigationsfertigations/days/dayscontinuoscontinuos leaching + collectionleaching + collectionmonitoringmonitoring : : fertigationfertigation, , leachateleachate, , assayassay: plants => nutrient uptake: plants => nutrient uptake

Experimental setup, Tuff, 1999.

Treatment DescriptionB Control A D A- Fertigation: First 1/3 irrigation only, 2/3 with

100% of referenceD C B Total applied- 65% of reference

A C D B- 20% fertigation and 45% as banded CRF.

Control C B A Total applied - 65% of reference

D C B C- Fertigation with 65% of reference level, no leaching period

B A Control D Total applied- 65% of reference

C D A D- Fertigation according to commercial recommendations, Reference treat

A Control B

C Total applied - 100% (reference)

Reference Treatment: 70 ppm N after planting, raising to 120 after 2 weeks

1. Fertilizer used for fertigation: 6-3-6 +6ME (Deshen Gat), ammonium/nitrate – 60:40

2. Applied controlled release fertilizer (CRF) “Multicote” (Haifa Chemicals), with a “tailor made”

composition of : 16.5-8.5-16.5

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37

45

25

41

4944

63

29

0

10

20

30

40

50

60

70

A B C D

N Use Efficiency(Shoots) & N Leaching Fraction - Basil grown on Tuff

% of N( Output/Input) % of N (Plant/Input)

22

46

11

42

22

55

24

48

0

10

20

30

40

50

60

A B C D

N Use efficiency (Shoots)& N Leaching Percentage -Basil grown on Perlite

% of N( Output/Input) % of N (Plant/Input)

TuffTuff

PerlitePerlite

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Lysimeters (substitute experiment in “real” soil)

21

Tensiometer

Wicks Sampler

2lit/hr emitters Rhizon soil moisture sampler

41

17

40

68

83

cm

cm

cmcm

cmcmcm

55

5-7

Drainage layercm

37

thermometer

5

Sandy LoamSandy Loam

Cumulative yield in lysimeter- grown basil plants

50

7450

78

57.67

102

127

66.67

109

135

20.67

18.670

20

40

6080

100

120

140

160

3.5 8 12Time from planting (weeks)

Yield (dry weight

g / lysimeter)

Treatment-A(100reference ) Treatment-B(80referenceTreatment-C(Ncoat 80) Treatment-D(Multigrow-80)

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Cumulative leaching of nitrogen in drainage of basil lysimeters

0.002.004.006.008.00

10.00

2 3 4 6 7 10 11 13 17 20 23 31 38 44 50 59 66 80

Time from planting (days)

Nitrogen leached

(g / lysimeter)

Treatment A(100 reference)Treatment B(80 reference)Treatment C(Ncoat-80)Treatment D(Multigrow-80)

Cumulative - P uptake g / lysimeterBASIL in lyzimeters

0.25

0.25

0.440.37

0.10

0.36

0.10

0.39

0.56

0.25

0.66

0.53

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

3.5 8 12Time (weeks)

P g

Treatment-A(100reference) Treatment-B(80referenceTreatment-C(Ncoat 80) Treatment-D(Multigrow-80)

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Important Features Summary

• Release Pattern, (shape, lag, lock off)

• Release Duration

• Differential Release N-P-K

• Temperature effect on Release

• Medium/Env. Cond. effect on Release

Additional points for consideration Additional points for consideration …………•• Microelements release (??)Microelements release (??)

•• Ammonium/Nitrate RatioAmmonium/Nitrate Ratio

•• Urea in the CRF (?)Urea in the CRF (?)

•• DegrabilityDegrability ((erodibilityerodibility)/Bio)/Bio--degrabilitydegrability of coatingof coating

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When are “real” advantages of the CRF vs. “More Conventional” alternative expected?

Depends on factors such :

• Culturing Conditions: field (row, whole bulk, orchard), greenhouse (soil or detached media), potting media (small, large)

• Medium or soil type: Light? Heavy? CEC? OM?

• Leaching: (irrigation system, rain-fed,),

• Nutrient loss mechanisms

• Balanced/Imbalanced nutrient supply (availability problems)

• Environmnetal aspects

• pH, Ec, Eh constrains

• Special needs: e.g. ionic species combinations of

ammonium-nitrate,, ammonium-P,

Future Needs,,,,,,, or ImprovementsFuture Needs,,,,,,, or Improvements• Improved utilization of advanced technologies , development of new concepts for preparing more cost-effective CRFs

• Better Quantification of the agronomic and economic advantages

• Better assessment of expected benefits to the environment

• Development/Standardization of teststests for characterizing the release performance of SRF/CRFs to improve

-- useruser’’s decisions decision--making process, making process,

-- industrial quality control, industrial quality control,

-- assist legislation efforts.assist legislation efforts.

•• Utilization of mechanisticUtilization of mechanistic--mathematical mathematical models models for for predictingpredictingrelease of nutrients under laboratory and field conditions, and release of nutrients under laboratory and field conditions, and as a as a design tool for technologistsdesign tool for technologists

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• Knowledge Integration to result inKnowledge Integration to result in: :

-- Better Use Instructions, Better Use Instructions,

-- Proper definitions of products Proper definitions of products

-- Improved/Relevant Performance InformationImproved/Relevant Performance Information

•• Users should be exposedUsers should be exposed to this knowledge to help them choose to this knowledge to help them choose SRF/SRF/CRFsCRFs professionally and on quantitative basisprofessionally and on quantitative basis

•• Agronomists, EnvironmentalistsAgronomists, Environmentalists should be should be exposedexposed to this to this knowledge to help them in better advising from both Agronomic knowledge to help them in better advising from both Agronomic (&economic) and Environmnetal points of view (&economic) and Environmnetal points of view

Thanks

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Specific Points in Case of Questions

Urea hydrolysis increases soil pH Urea hydrolysis increases soil pH and losses of and losses of AmmoniaAmmonia

Nitrification Nitrification -- FIRST STEP FIRST STEP -- inhibited by:inhibited by:specific inhibitorsspecific inhibitors,

2NH+4 + 3 O2 => 2NO2NO--

22 + 2H+ 2H22O + 4 HO + 4 H++

((NitrosomonasNitrosomonas, , NitrosospiraNitrosospira))

2NO2NO--22 + O+ O2 2 => 2NO=> 2NO--

33 ((NitrobacterNitrobacter) () (high pH, NHhigh pH, NH33))

(NH2)2CO + HH++ + 2H2O => 2NH+4 + HCO-

3

(NH4)2CO3 NHNH33 + H2CO3

2NO2NO--22

High pH and AmmoniaHigh pH and Ammonia reduce activity of Nitrobacter and hence cause accumulation of “toxic” Nitrite during nitrification

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Application of local high urea concentrations (e.g., basal placement) may cause:

1. Increased pH (due to formation of ammonium carbonate)

2. Increased ammonia levels due to the decomposition of the ammonium carbonate and high pH. In calcareous soils the effect is dramatically enhanced!!

3. In containers, with restricted volume – the local concentration of applied urea may be high (if not carefully applied) and may stimulate processes like in 1 and 2.

4. High pH and ammonia may damage roots and also affect the fast oxidation of nitrite into nitrate and cause accumulation of Toxic levels of Nitrite

Any system providing metered supply or controlled supply of urea has a great potential to reduce the above effects.

Too high (local) levels of applied urea may turn soon into Ammonium after urea the hydrolysis (~half a day).

Exposing plants to high loads of ammonium and particularly in containers (detached media) with restricted volume and neutral to slightly acidic pH, may induce further acidification due to nitrification or ammonium uptake by plants.

Metered or Controlled Supply of the ammoniacal source (including urea) is not expected to cause dramatic acidification, particularly when a balanced supply of urea/ammonium and nitrate is given.

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Potting media

LEVEL 1 Fe in drainage (Melisa exp)

0.0

0.5

1.0

1.5

20 40 60 80 100 120 140 160days

Acc

umul

Fe

DSN 482 MEIO DSN 496 W/0 ME OSMOCOTLEVEL 2 Zn indr ainage

01234567

20 70 120 170days

Acu

umul

Zn

D SN 482 MEIO D SN 496 W/0 ME OSMOCOT

AccumulatiAccumulatingng FeFe with with leaching timeleaching time

Accumulatingccumulating ZnZn with with leaching timeleaching time

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