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List trial yields
Farm yields
UK Oilseed rape yield trends
World Record 6.7 t/ha
UK 2015
Seed number determination
Determined by photosynthesis during a 200-300oCd period after flowering (2-3 weeks)
Pod & seed numbers
0
5
10
15
20
25
30
0 5000 10000 15000
pods/m2
Se
ed
s p
er
po
d
0
20000
40000
60000
80000
100000
se
ed
s/m
2
Optimum canopy size
0
0.5
1
0 2 4 6
Green area index
Fraction of light intercepted
Fraction of
light
intercepted
Green area index
Seed Filling
0
2
4
6
8
10
12
14
15-Mar 14-Apr 14-May 13-Jun 13-Jul
Bio
ma
ss
(t/h
a)
seed
pod wall
stem
Leaf
mid-flowering
Seed number
Seed size
Dense or lodged canopies
• Fewer leaves
• Poor light penetration
to leaves & lower pods
• Less seed filling
• Lodging reduces yield by up to 50%
Nitrogen for optimum canopy
y = 0.0219x
R2 = 0.8661
0
1
2
3
4
5
6
7
0 100 200 300
N uptake (kg/ha)
Gre
en
Are
a In
de
x (G
AI)
Canopy Management rules
• Target an optimum GAI of 3.5 units
• Takes 50kg N/ha to make 1 GAI
• Soil and crop N (SNS) ~ 100% efficient
• Fertiliser N ~ 60% efficient
Example Kg/ha N
Target N needed in crop (3.5 GAI x 50 kg N for each GAI)
175
GAI =1 at end Feb Soil mineral N
50 25
Shortfall (Target N – crop & soil N)
100
Fertiliser requirement
(Shortfall 0.6)
167
Calculating N inputs
Example Kg/ha N Kg/ha N
Target N needed in crop (3.5 GAI x 50 kg N for each GAI)
175 175
GAI =1 at end Feb Soil mineral N
50 25
100 25
Shortfall (Target N – crop & soil N)
100 50
Fertiliser requirement
(Shortfall 0.6)
167 83
Calculating N inputs
GAI=2
How to estimate crop N: OSR
• Digital photo for GAIs of up to 2.5 • Use BASF or Yara apps
• Crop fresh weight for GAIs above 2.5 • Record fresh weight in kg of 1m x 1m area
• Multiply by 0.8 to give GAI
• Fraction of soil covered by crop • Third: 25 kg N/ha
• Half: 50 kg N/ha
• Three quarters: 100 kg N/ha
• Crop height • 10cm: 35-45 kg N/ha
• 15cm: 55-65 kg N/ha
• 20cm: 75-85 kg N/ha
High yielding crops
• Crops with a yield potential of more than 3.5 t/ha require more N
• Apply an extra 30 kg/ha for each 0.5 t above 3.5 t/ha
• High yielding crops need extra N to prolong seed filling
Optimum Plant population
4.0
4.2
4.4
4.6
4.8
20 40 80 120 160
Seed rate per m2
Yie
ld (
t/h
a)
Excalibur
Castille
PR45D03
25 plants/m2 35 plants 59 plants 76 plants 98 plants
Optimum seed rate
26 seeds/m2
Summary: Optimum plants/m2
0
20
40
60
80
100
Yor
ks09
Yor
ks10
Here
11
Norf1
1
Yor
ks11
Here
12
Norf1
2
Yor
ks12
Optim
um
pla
nts
/m2
Conventional
Hybrid
Yield effects (Metconazole applied March GS3.3 to 3.5)
-0.2
-0.1
0
0.1
0.2
0.3
GAI at application in March
Ch
an
ge
in
yie
ld (
t/h
a)
du
e to
me
tco
na
zo
leN=14
A
N=13
B
N=5
B
<0.8 >2.00.8 to 2.0
Future Challenges
• Canopy Management: continue to increase usage • Limited by pigeons!
• More reliable plant establishment • Cabbage stem flea beetle
• Increase rooting below 40cm soil depth
• Improve disease control: Light leaf spot
• Increase Sulphur use
• Other • Low yields from close rotation
• Turnip Yellow Virus
• Verticillium wilt