Nitrogen Management for Enhanced Protein: Source and Timing of N Applications in Spring Wheat

C.A. Grant1, C.D. Rawluk1, R.M. McKenzie2, D.N. Flaten3 and A.M. Johnston4

1AAFC Brandon Research Centre, 2Alberta Agriculture, 3University of Manitoba, 4Potash and Phosphate Institute

weather

Soil Characteristics

Factors Affecting Protein Content of WheatFactors Affecting Protein Content of Wheat

N Movementto grain

N uptake

Grain yield

Crop Genetics

Seeding Date

Agronomy

N supply and release

Effect of N on grain yield and protein Effect of N on grain yield and protein concentrationconcentration

1.4

1.8

2.2

2.6

0 40 80 120 160 200

N Rate (kg/ ha)

Gra

in Y

ield

(T/h

a)

12

13

14

15

16

17

Pro

tein

Conce

ntr

ati

on (

%)

YieldProtein

Balance Crop Demand with Nitrogen SupplyBalance Crop Demand with Nitrogen Supply

Crop Demand

Nitrogen Supply

In-crop N where crop demand exceeds soil supply

In-Crop N Management For Protein• Is the extra N needed?

• Source?– Urea, UAN, ammonium nitrate

• Timing?– Seeding, tillering , boot, anthesis

• Placement?– Foliar, soil-applied

MethodologyMethodology• Field studies from 1997-2000 at several

sites in Black Soil Zone of Canadian prairies

• Hard red spring wheat

• 75 kg N ha-1 applied at seeding compared to 60 kg N ha-1 applied at seeding plus 15 kg N ha-1 as in-crop application

Nitrogen source and timing effects on wheat Nitrogen source and timing effects on wheat protein contentprotein content

10.0

12.0

14.0

16.0

18.0

Pro

tein

(%

)

Bdn - 97

Mel - 9

7

Lowes -

97

Bdn - 98

Mel - 9

8

Lowes -

98

Bdn - 99

Mel - 9

9

Lowes -

99

At SeedingAm. Nitrate at Boot

Change in protein content by 15 kg N per ha as Change in protein content by 15 kg N per ha as AN at boot as compared to at seeding AN at boot as compared to at seeding

-0.6

-0.2

0.2

0.6

1.0

Pro

tein

(%)

Predicting the need for in-crop NPredicting the need for in-crop N

• Good growing conditions– yield potential exceeds the target yield

• Visual N deficiency symptoms • Tissue N levels• Use of SPAD meter–Chlorophyll meter–Assesses “greeness”

Protein Content and Leaf N Content Protein Content and Leaf N Content as Related to Spad Meter Readingsas Related to Spad Meter Readings

R2 = 0.9529

R2 = 0.9771

40

42

44

46

11.0 12.0 13.0 14.0 15.0

Protein (%)

Chlo

rophyl

l

3.0

3.5

4.0

4.5

5.0

Leaf

N (

%)

Chlorophyll

Leaf N

Melfort, 1999

Nitrogen source and timing effects on increase Nitrogen source and timing effects on increase in wheat protein content above N at seedingin wheat protein content above N at seeding

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Pro

tein

(%

)

Tillerin

gBoot

Anthesis

UAN

Urea

Nitrogen source and timing effects on increase Nitrogen source and timing effects on increase in wheat protein content above N at seedingin wheat protein content above N at seeding

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Pro

tein

(%

)

UAN Tille

ring

Urea T

illerin

g

UAN Boot

Urea B

oot

UAN Anth

esis

Urea A

nthesis

No NBPT

NBPT

Nitrogen source and timing effects on increase Nitrogen source and timing effects on increase in wheat protein content above N at seedingin wheat protein content above N at seeding

-0.2

-0.1

0.0

0.1

0.2

0.3

Pro

tein

(%)

UAN

AM. Nitrate

Early Seeding Date

Nitrogen source and timing effects on increase Nitrogen source and timing effects on increase in wheat protein content above N at seedingin wheat protein content above N at seeding

-0.2

-0.1

0.0

0.1

0.2

0.3

Pro

tein

(%

)

Tillerin

gBoot

Anthesis

UAN

Am. Nitrate

Late Seeding Date

Uptake of Soil- and Foliar-Applied Urea by Uptake of Soil- and Foliar-Applied Urea by Wheat in two Growth Chamber StudiesWheat in two Growth Chamber Studies

0

20

40

60

80

N R

ecov

ery

(%)

Soil Soil +NBPT

Foliar Foliar +NBPT

Foliar +Agral 90

Exp. 1Exp. 2

50 ppm base N

Foliar Application of NFoliar Application of N

• Under dry conditions, late N applications to soil may be unavailable

• Foliar applications may allow N uptake by plant– greater advantage in drier areas?

SummarySummary• Benefit of in-crop N was variable– often only minor benefit over application of N at

seeding– consider cost of extra operation

• Ammonium nitrate >urea >UAN in increasing protein content– volatilization losses from urea– little actual foliar uptake

• UAN may be beneficial with late application under dry conditions

The EndThe End

Thank you to Western Grains Research Foundation, ARDI, Westco, Envirotest Laboratories, Simplot and MII for their support of this research