Response to N rate and timing (a side by side comparison to
NVTs) Merredin. Trial Report 2015
Christine Zaicou-Kunesch, DAFWA, Geraldton Office.
Introduction
A better understanding of how tactical decisions such as nitrogen timing and rate influence
varietal performance in the low rainfall will enable confidence in decision making at seeding and
throughout the season. N can be applied at any time up until anthesis but how it affects the
crop changes with application time.
In general early applied N (at seeding or during tillering) has the greatest effect on yield by
increasing or maintaining tillers but is also most likely to promote excessive crop vigour, an
issue if moisture becomes limiting. N applied later when potential grain number has been set is
more likely to influence grain protein.
Knowing how late N can be applied and still contribute to grain yield is important. The later N is
applied allows the growers to be more confident with how the season is progressing and the
likely yield potential. This is one trial in a series across the grainbelt which are co-located with
the national variety trials.
Aim
Determine the value of nitrogen rates and timing on production of grain and grain quality for
profitable wheat systems
Trial details
Property
Merredin
Red loam
Soil type
depth:
pH (CaCl2):
NH4 (ug/g):
NO3 (ug/g):
0-10
5.2
17
55
10-20
5.4
2
38
Crop
Wheat varieties: Mace and Hydra
Paddock rotation
2014: wheat; 2013: canola; 2012: wheat
Treatments
See table 1 below
Replicates
3
Sowing date
16/5/2015
Seeding rate
Targeted 120 plants/m2
Fertiliser (kg/ha)
80kg/ha double Super
Rainfall
page 1
Table 1: Nitrogen treatments applied to wheat agronomy trial at Merredin
Total N
(kg/ha)
0
10
30
30
30
50
50
50
70
70
70
NVT
N tr
0N
10N
30N
10N 20N
10N 0N 20N
10N 40N
10N 0N 40N
10N 20N 20N
10N 20N 40N
10N 40N 20N
30N 20N 20N
As per NVT
N(kg/ha)
@Seeding
0
10
30
10
10
10
10
10
10
10
30
23
N(kg/ha)
(Zd 21)
0
0
0
20
0
40
0
20
20
40
20
0
N(kg/ha)
(Zd 31)
0
0
0
0
20
0
40
20
40
20
20
Acknowledgements




DAFWA colleagues Bob French and Brenda Shackley for trial development
The Grain Crop Agronomy Reference group (managed by GRDC), for their support with
research development in 2015.
The project ‘Tactical wheat agronomy for the west (DAW00249) is funded by GRDC and
DAFWA
Kalyx for trial management and DAFWA’s Bruce Haig for technical support with nitrogen
application, data collection and management
Important disclaimer
The Chief Executive Officer of the Department of Agriculture and Food and the State of Western
Australia accept no liability whatsoever by reason of negligence or otherwise arising from the
use or release of this information or any part of it. Copyright © Western Australian Agriculture
Authority, 2015
page 2
Trial layout
15ME23: Merredin
Bank1
N applied
kg/ha
Buffer
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
10N 20N 40N
30N 20N 20N
0N
10N 0N 40N
10N 40N
30N
NVT
30N 20N 20N
10N
10N 20N
10N 40N 20N
NVT
Variety
1
2
3
4
5
6
7
8
9
10
11
12
Buffer
page 3
Bank2
N applied
kg/ha
Buffer
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
10N 40N 20N
10N 20N 20N
10N 20N
30N
10N
0N
10N 20N 20N
10N 0N 20N
10N 40N
10N 0N 40N
10N 0N 20N
10N 20N 40N
Variety
Buffer
Bank3
N applied
kg/ha
Buffer
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
10N
10N 0N 20N
10N 40N
NVT
10N 40N 20N
10N 20N
10N 20N 40N
10N 0N 40N
30N
30N 20N 20N
0N
10N 20N 20N
Variety
Buffer
Bank4
N applied
kg/ha
Buffer
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
0N
30N 20N 20N
30N
10N 20N 20N
10N 20N 40N
10N 20N
10N 0N 40N
10N 40N 20N
NVT
10N 40N
10N 0N 20N
10N
Variety
Buffer
Bank5
N applied
kg/ha
Buffer
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
NVT
10N 0N 40N
10N
10N 20N
0N
NVT
10N
30N 20N 20N
10N 40N 20N
0N
10N 20N 40N
30N 20N 20N
Variety
Buffer
Bank6
N applied
kg/ha
Buffer
Hydra
Hydra
Hydra
Hydra
Mace
Mace
Mace
Mace
Hydra
Hydra
Hydra
Hydra
10N 0N 20N
10N 40N 20N
10N 20N 40N
10N 40N
30N
10N 0N 20N
10N 20N 20N
10N 40N
10N 20N 20N
10N 0N 40N
30N
10N 20N
Variety
Buffer