nitrogen management for enhanced protein: source and timing of n applications in spring wheat c.a....
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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