timothy w. walker, ph. d. associate...

Methods to Improve Nutrient Use Efficiency in Rice

6R‐2/Room 4Tuesday 11:10‐11:56

Wednesday 10:10‐10:56

Timothy W. Walker, Ph. D.Associate Agronomist

662‐822‐2291

Nitrogen Use Efficiency

NUE = Grain yield (lb/acre)Nitrogen applied (lb/acre)


Yield

Genetics

Variety Selection Breeding

Management

Agronomic Pest


N Rate

Decrease N Rate

Account for Soil Supply

N‐ST*R (U of A)

Rate Response

Account for Plant Need

Chlorophyll Plant Area BoardSensor‐based

Maintain N Rate

Prevent Loss

Ammonia

Agrotain Water

Nitrate

Water Nitrification Inhibitors

Nitrogen Use EfficiencyMaintain N

Rate

Prevent Loss

Ammonia

Agrotain Water

Nitrate

Water Nitrification Inhibitors

Urea’s Reaction ProducesNH3 Gas

2 NH3 ammonia gas on soil surfaceor in flood

- H2O & CO2

CO(NH2)2 (NH4)2CO3 2 NH4+ + 2 OH-

urea urease (pH ~ alkaline) ammonium salt in soil

Note: Urea’s reaction in soil initially is alkaline and increases soil pH causing ammonia volatilization loss if not incorporated in soil quickly.

Slide borrowed from R. Norman

Ammonia Volatilization of Urea Applied to a Conventional Tilled and a Stale-Seedbed Silt loam soil (RREC, 2001)

[N source LSD0.05 = 3.1% of applied N]

0

5

10

15

20

25

30

35

0 5 10 15 20 25

Time (days)

Vola

tiliz

atio

n (%

of a

pplie

d N

)

Ammonia VolatilizationEnds at ~10 Days

↓Stale-Seedbed

Conventional Till

Griggs etal., 2007; SSSAJ


Ammonia Volatilization of 15N-labeled Urea and Ammonium Sulfate From a Perry Clay Soil14 Days before Flooding (SEREC, 2000)

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18 20 22

Time (days)

Vol

atili

zatio

n (%

of a

pplie

d N

)

Ammonium Sulfate Urea

Urea

Ammonium Sulfate

Ammonia Volatilization Losses(Clay soil)

Flood

Griggs et al., 2007; SSSAJ


Rice Research Station – fertility and Agronomy Project

i

e-h d-h

a

a-d a-da-e a-c

y = 520.4x + 6697.5

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10 DPF 7 DPF 4 DPF 1 DPF

Yie

ld (l

b/A

)

Application time (Days Prior to Flooding)

UreaAgrotain-UreaLinear (Urea)

581 lbs7 %

1238 lbs15 %


0

5

10

15

20

25

3 6 9 12 15 18 21

NH4‐N lo

ss (%

of t

otal

applied)

Time (days)

UreaAS‐UreaASSuper‐UAgrotain‐Urea


(Urease inhibitor only) (Urease and nitrification inhibitors)

a-d a-da-e a-c

c-gb-f b-f

a-c

5000

5500

6000

6500

7000

7500

8000

8500

9000

10 DPF 7 DPF 4 DPF 1 DPF

Yie

ld (l

b/A

)

Application time (Days Prior to Flooding)

Agrotain-UreaSuper-U

Ammonia Volatilization

0

2

4

6

8

10

12

0 5 10 15 20

% of a

pplied

Days

NH3 Volatilization Loss

urea

ams

agrotain

Data from Tunica clay. Dillon and Walker, unpublished

Urea vs Agrotain

LSD = 7Source x Timing (P = 0.0024)

8224

8566

8269

8599

7806

8361

8500 8452

7400

7600

7800

8000

8200

8400

8600

8800

10 7 4 1

lb/acre

AgrotainUrea

LSD = 453

Urea vs Agrotain


7420

7818

7586

7155

7860

7710

6800

7000

7200

7400

7600

7800

8000

10 7 2

AgrotainUrea

LSD = 361

Agrotain vs Super U


8224

8566

8269

8599

8056

8488

8113

8331

7700

7800

7900

8000

8100

8200

8300

8400

8500

8600

8700

10 7 4 1

AgrotainSuper U

LSD = 453

Testing the Mechanism – Product Evaluation

• Agrotain is the only ureaseinhibitor recommended in Arkansas.

• Other products unproven to inhibit NH3 loss include– Nutrisphere– N‐Zone– Extend– Upgrade

Lab EvaluationUpgrade

05

1015202530354045

0 5 10 15

Cumulative NH3Loss

(% of a

pplied N‐fe

rtilizer)

Time (days)

Urea Agrotain‐Urea Upgrade‐Urea

Source: Norman and Roberts (unpublished data)

Lab EvaluationN‐Zone

08

16243240485664

0 5 10 15

Cumulative NH3Loss

(% of a

pplied N‐fe

rtilizer)

Time (days)

Urea Agrotain‐Urea N‐Zone‐Urea


Lab EvaluationNutrisphere

08

16243240485664

0 5 10 15

Cumulative NH3Loss

(% of a

pplied N‐fe

rtilizer)

Time (days)

Urea Agrotain+Urea Nutrisphere+Urea Ammonium Sulfate

Source: Franzen et al. (2011, in press) J. Plant Nutr.0.25% Nutrisphere added

Lab EvaluationExtend

05

1015202530354045

0 5 10 15

Cumulative NH3Loss

(% of a

pplied N‐fe

rtilizer)

Time (days)

Urea Agrotain‐Urea Extend‐Urea


Nitrification/Denitrification

2NH4+ + 3O2 2NO2‐ + 2H2O + 4H+Nitrosomonas

2NO2‐ + O2 2NO3‐Nitrobacter

NO3‐ + H2O NO, N2O, N2 (gases)Permanent Flood

Nitrogen Stabilizers

113

131137

164

100

110

120

130

140

150

160

170

180

10 DBF 2 DBF

bu/ac 60120

Urea Conversion to NO3‐

Time (days)

0 3 6 9 12 15 18 21 24 27

NH

4 rem

aini

ng (%

of i

nitia

l)

0102030405060708090

100110

DulaneyF13SF14WalkerCircleHLADavis

Urea Conversion to NO3‐

Soil A K T1/2 R2

‐‐‐‐‐‐‐‐‐‐%‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐d‐1‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐d‐‐‐‐‐ ‐‐Unit less‐‐

LA 106.3244 (8.6832) 0.1046 (0.0187) 6.6 0.945

F13S 98.1749 (5.0216) 0.0840 (0.0095) 8.3 0.971

Dulaney 92.3076 (8.0813) 0.0708 (0.0139) 9.8 0.910

Davis 101.8352 (7.4631) 0.1353 (0.0218) 5.1 0.961

CircleH 103.3625 (7.8772) 0.1447 (0.0242) 4.8 0.960

F14 105.0458 (7.1418) 0.1573 (0.0236) 4.4 0.970

Walker 96.3323 (5.5211) 0.1672 (0.0212) 4.1 0.977

Nitrification Rate of UreaNitrification of Urea in two Soils

Days0 5 10 15 20 25 30 35

% u

rea-

N a

s N

O3-

N

0

20

40

60

80

100

120

Calhoun soilDewitt soil

Unpublished data: Golden et al. (2009)Slide borrowed from R. Norman

Grain Yield

LSD = 7Source x Timing (P = 0.0024)8218

8071 8041 8069

8235

7467

7642

7858

7994

7000

7200

7400

7600

7800

8000

8200

8400

43% Urea ENTEC Super U Agrotain

2DBF10DBF

LSD = 421

Data collected at DREC2010

Sharkey clay soil

Nitrification InhibitorNutrisphere

05

101520253035404550

Soil Inorganic N (p

pm)

NO3‐N NH4‐N

Source: Franzen et al. (2011, in press) J. Plant Nutr.90 lb urea‐N/acre; LSD0.05 (8.4 ppm for NO3 and 4.5 ppm for NH4)Data from Hazelton, North Dakota)

Sensor‐based

1NUE Fixed = 35%NUE Sensor = 38%

$ Fixed = $447$ Sensor = $446

Commercially Available Active Sensors

Photo courtesty of B. Tubana

Rice Info on the Webwww.rice.msstate.edu

Special Thanks

• Dr. Dustin Harrell• Dr. Brenda Tubana• Mr. Kevin Dillon• Mr. Paxton Fitts• Dr. Rick Norman• Dr. Nathan Slaton• Dr. Bobby Golden• Dr. Trent Roberts

Special Thanks

timothy w. walker, ph. d. associate...

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