field-scale sensor evaluation ken sudduth, newell kitchen, scott drummond usda-ars columbia mo
TRANSCRIPT
Field-Scale Sensor EvaluationField-Scale Sensor Evaluation
Ken Sudduth, Newell Kitchen, Scott Drummond Ken Sudduth, Newell Kitchen, Scott Drummond
USDA-ARSUSDA-ARS
Columbia MOColumbia MO
ObjectivesObjectives
Investigate row-to-row variability in field-scale Investigate row-to-row variability in field-scale reflectance sensor datareflectance sensor data
Document differences between data collected with Document differences between data collected with Holland Scientific Crop Circle (amber) and NTech Holland Scientific Crop Circle (amber) and NTech GreenSeeker (green)GreenSeeker (green)
N Application N Application SystemSystem
6-row system with 6-row system with sensors mounted sensors mounted over rows 2 and 5 over rows 2 and 5
System tested on System tested on 7 producer sites 7 producer sites in 2004 in 2004
Control HardwareControl Hardware
Application Control System
Green GreenSeeker
1
Green GreenSeeker
2
Crop Circle 3
Crop Circle 4
Laptop Computer
GPS
Stored Data:All sensor dataGPS dataProcessed dataValve commands
1x, 2x, and 4x Solenoid Valves
Analysis of Analysis of Response Plot Response Plot Sensor DataSensor Data
Each field site included two Each field site included two strips of N-rate response strips of N-rate response plotsplots
Reflectance data were Reflectance data were collected at the time of collected at the time of sidedress N applicationsidedress N application
Mean reflectance ratio and Mean reflectance ratio and NDVI were calculated for NDVI were calculated for each of the four sensors for each of the four sensors for each 50-foot ploteach 50-foot plot
Response Plot Reflectance Ratio DataResponse Plot Reflectance Ratio Data
N application at the Diederich (D) field was done near N application at the Diederich (D) field was done near dusk, with only diffuse lighting. Work at all other field dusk, with only diffuse lighting. Work at all other field sites was completed before 6 pm.sites was completed before 6 pm.
0.1 0.2 0.3 0.4 0.5 0.6 0.7Gre e n S e e ke r R a tio , R o w 2
0.1
0.2
0.3
0.4
0.5
Cro
p C
ircl
e R
atio
, Ro
w 2
P
PP
PP
P PP
PP P
PPP
PP
PPP PP
P
P P
C 1C 1
C 1C 1C 1C 1
C 1C 1C 1
C 1
C 1C 1C 1
C 1C 1
C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1
C 1
C 1C 1
C 1
C 1C 1
C 1 C 1
C 1
C 1C 1
C 1
C 1C 1
C 1
C 2
C 2
C 2C 2
C 2
C 2
C 2C 2C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2C 2
C 2C 2C 2C 2
C 2C 2
C 2
C 2C 2
C 2C 2
C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2
D
D
DD
DDD
D
D
D
DD
D
D
DD
D
D
D
DD
D
D
D
D
D
DDD
D
D
D
DD
D
DDD
DD
D
D
D
D
D
D
BBBB
BB
BB
B
B
B
BB
B
B B B BBBBBBBBBBBB
B BBBBBBBBB
BBB
BB
B BBB
BB
B
BB BB
BBB
BB B
BB
BB
B
BBBB
BBB B
B
BBB
B
B
BB
BBB
B
S
S
S
S
S
S
S
S
S
SS
S SS
SS
SSSSSS
S
S
S S
S
S
S SSS
S
SS
S
SS
S
S
S
S
SS
S
S
S
S
WW
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W
W
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WW
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W
WW
W
W
WW
WW
WW
W
W
WWWW
WW
W
WW W
W
W
W
W
W
HHHH H
HH
HHHHHHH
H H
HHHHHH H
H
H
HHH
H
HHH
HHH
HH
H
HHHHH
HHH
0.1 0.2 0.3 0.4 0.5 0.6 0.7Gre e n S e e ke r R a tio , R o w 5
0.1
0.2
0.3
0.4
0.5
Cro
p C
ircl
e R
atio
, Ro
w 5
PP
PPP P
PPPP PP
PP
P PP
PPP PP
PP
C 1C 1
C 1 C 1C 1C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1 C 1C 1
C 1C 1C 1
C 1
C 1C 1
C 1
C 1C 1C 1C 1C 1
C 1
C 1
C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1
C 2
C 2C 2
C 2C 2
C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2C 2
C 2
C 2C 2C 2
C 2C 2C 2
C 2
C 2
C 2C 2C 2
D
DDD
D
D
D
D
DD
DD
D
D
D
DD
DD
D
D
D
D
DD
DD
DD
D
D
D
D
DD
D
DDD
DD
D
D
DD
D
BBBB
BB
BBB
B
B
B BB
B BB BBBB
BBBB
BBB B B
BB
BBB BB BBBBB
BB
BBBB B
BB
BBB
B
B
BB
B B B
BB
BBB
B
BBB
B
BBBB
BBBB
BB
BBBBB
S
S
S
S
S
SS
S
SS
SS
S
S
SS
S
S
SSSS
S
S
S
S
S
S
S
S
S
SS
S
SS
SS
SS
SS
SSS
S
S
S
WW
WW
W
WW
W
W
W
WW
WW
W
WW
WW
W WWW
WWW
W
W
W
W
W
WW
W
W
W
W
W
W W
WWW W
WW
HHHH
H
H
HHHH
HHHH
HH
HHHH H HH
H
HH
HH
HH HH
H
H HH
H H
HHH H H HH
H
Response Plot Reflectance Ratio DataResponse Plot Reflectance Ratio Data
Response Plot Sensor ComparisonDiederich Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
105 115 125 135 145
Response Plot Number
Re
fle
cta
nc
e R
ati
o,
Vis
/NIR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Reflectance Ratio DataResponse Plot Reflectance Ratio Data
Response Plot Sensor ComparisonCopeland Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
26 36 46 56 66 76 86 96
Response Plot Number
Re
fle
cta
nc
e R
ati
o,
Vis
/NIR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonSchnarre Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
237 247 257 267 277
Response Plot Number
Re
fle
cta
nc
e R
ati
o,
Vis
/NIR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Reflectance Ratio DataResponse Plot Reflectance Ratio Data
Response Plot Sensor ComparisonSchnarre Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
237 247 257 267 277
Response Plot Number
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonCopeland Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
26 36 46 56 66 76 86 96
Response Plot Number
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonDiederich Knee-High 2004
0
0.1
0.2
0.3
0.4
0.5
105 115 125 135 145
Response Plot Number
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Row-to-row differences are apparentRow-to-row differences are apparent
Is there an ambient light effect?Is there an ambient light effect?
Within a row, relative differences in Within a row, relative differences in sensor output are generally sensor output are generally consistent between sensor typesconsistent between sensor types
Scaling differences are apparent Scaling differences are apparent between sensor typesbetween sensor types
Amber reflectance vs. green reflectance?Amber reflectance vs. green reflectance? Normalize data - divide by mean of each Normalize data - divide by mean of each
sensor reading within each field sensor reading within each field
Normalized Normalized Reflectance Ratio DataReflectance Ratio Data
0.4 0.8 1.2 1.6 2Gre e n Se e ke r N o rm a lize d R a tio , R o w 2
0.4
0.8
1.2
1.6
2
Cro
p C
ircl
e N
orm
aliz
ed
Ra
tio, R
ow
2
P
P
P
PP
P PP
PP P
PP
PP
P
PPP
PP
P
P P
C 1C 1
C 1C 1C 1C 1C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1
C 1
C 1C 1
C 1
C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1C 1
C 1
C 2C 2
C 2C 2
C 2
C 2
C 2C 2C 2C 2
C 2C 2
C 2C 2
C 2
C 2C 2C 2
C 2C 2C 2C 2
C 2C 2
C 2
C 2C 2
C 2C 2C 2C 2
C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2
D
D
DD
DDD
D
D
D
DD
D
D
DD
D
D
D
DD
D
D
D
DD
DDD
D
D
D
DD
D
DD D
DD
D
D
D
D
D
D
BBB
B
BB
B
B
B
B
B
BB
B
B B B BB
BBBBBB
BBBB
B BBBBBBBBB
B
BB
B
B
BBB
B
BB
B
BB BB
BBB
BBB
BB
BB
B
BBBB
BBB B
B
BBB
B
B
BB
BB
B
B
S
S
S
S
S
S
S
S
S
SS
S SS
SS
SSSSSS
S
S
S S
S
S
S SSSS
SS
S
SS
S
S
S
SSS
S
S
S
S
WW
W
WW
WW
W
W
WW
WWW
WW WW
W
WW
W
W
WW
WW
WW
W
W
WWWW
WW
W
WW W
W
W
W
W
W
HHHH H
HH
HHHH
HHH
H H
HHHHHH H
H
H
HHH
H
HHH
HHH
H
H
H
HHHHH
HHH
0.4 0.8 1.2 1.6 2Gre e n Se e ke r N o rm a lize d R a tio , R o w 5
0.4
0.8
1.2
1.6
2
Cro
p C
ircl
e N
orm
aliz
ed
Ra
tio, R
ow
5
P
PP
P
P PP
PP
P PP
PP
PPP
P
PP PP
PP
C 1C 1C 1 C 1
C 1C 1C 1C 1C 1
C 1C 1C 1C 1C 1C 1C 1
C 1C 1C 1
C 1
C 1C 1
C 1
C 1C 1C 1C 1C 1
C 1
C 1
C 1C 1
C 1C 1C 1
C 1C 1
C 1C 1
C 2C 2
C 2C 2C 2C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2
C 2
C 2C 2
C 2C 2
C 2
C 2C 2
C 2
C 2C 2
C 2C 2C 2
C 2
C 2C 2C 2
C 2C 2C 2
C 2
C 2C 2C 2C 2
D
DD
DD
D
D
D
DD
DD
DD
D
DD
DD
D
D
D
D
DD
DD
DD
D
D
D
D
DD
D
DDD
DD
D
D
DD
D
BBBB
B
B
BBB
B
B
B BB
B BB BBBB
BBBB
BBB B B
BB
BBBBB BBB
BB
BB
BBB
B BB
B
BBB
B
B
BB
BBB
BB
BBB
B
BB
B
B
BBB
BB
BBBB
BB
BBBB
SS
S
S
S
SS
S
SS
SS
S
S
SSS
S
SSSS
S
S
S
S
S
S
S
S
S
SS
S
SS
SS
SS
SS
SSS
S
S
S
WW
WW
W
WWW
W
W
WW
WW
W
WW
WW
WWWW
WWWW
W
W
W
W
WW
W
W
W
W
W
WW
WWWW
WWH
HHH
H
H
HHHH
HHHH
H
H
HHH
H H H
H
H
HH
HH
HH HH
H
HH
H
H H
HHH H H HH
H
0.1 0.2 0.3 0.4 0.5 0.6 0.7Gre e n S e e ke r R a tio , R o w 2
0.1
0.2
0.3
0.4
0.5
Cro
p C
ircl
e R
atio
, Ro
w 2
P
PP
PP
P PP
PP P
PPP
PP
PPP PP
P
P P
C 1C 1
C 1C 1C 1C 1
C 1C 1C 1
C 1
C 1C 1C 1
C 1C 1
C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1
C 1
C 1C 1
C 1
C 1C 1
C 1 C 1
C 1
C 1C 1
C 1
C 1C 1
C 1
C 2
C 2
C 2C 2
C 2
C 2
C 2C 2C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2C 2
C 2C 2C 2C 2
C 2C 2
C 2
C 2C 2
C 2C 2
C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2
D
D
DD
DDD
D
D
D
DD
D
D
DD
D
D
D
DD
D
D
D
D
D
DDD
D
D
D
DD
D
DDD
DD
D
D
D
D
D
D
BBBB
BB
BB
B
B
B
BB
B
B B B BBBBBBBBBBBB
B BBBBBBBBB
BBB
BB
B BBB
BB
B
BB BB
BBB
BB B
BB
BB
B
BBBB
BBB B
B
BBB
B
B
BB
BBB
B
S
S
S
S
S
S
S
S
S
SS
S SS
SS
SSSSSS
S
S
S S
S
S
S SSS
S
SS
S
SS
S
S
S
S
SS
S
S
S
S
WW
W
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WW
W
W
W
W
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W
WW
WW
W
WW
W
W
WW
WW
WW
W
W
WWWW
WW
W
WW W
W
W
W
W
W
HHHH H
HH
HHHHHHH
H H
HHHHHH H
H
H
HHH
H
HHH
HHH
HH
H
HHHHH
HHH
0.1 0.2 0.3 0.4 0.5 0.6 0.7Gre e n S e e ke r R a tio , R o w 5
0.1
0.2
0.3
0.4
0.5
Cro
p C
ircl
e R
atio
, Ro
w 5
PP
PPP P
PPPP PP
PP
P PP
PPP PP
PP
C 1C 1
C 1 C 1C 1C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1 C 1C 1
C 1C 1C 1
C 1
C 1C 1
C 1
C 1C 1C 1C 1C 1
C 1
C 1
C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1
C 2
C 2C 2
C 2C 2
C 2C 2
C 2
C 2
C 2
C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2C 2
C 2
C 2C 2C 2
C 2C 2C 2
C 2
C 2
C 2C 2C 2
D
DDD
D
D
D
D
DD
DD
D
D
D
DD
DD
D
D
D
D
DD
DD
DD
D
D
D
D
DD
D
DDD
DD
D
D
DD
D
BBBB
BB
BBB
B
B
B BB
B BB BBBB
BBBB
BBB B B
BB
BBB BB BBBBB
BB
BBBB B
BB
BBB
B
B
BB
B B B
BB
BBB
B
BBB
B
BBBB
BBBB
BB
BBBBB
S
S
S
S
S
SS
S
SS
SS
S
S
SS
S
S
SSSS
S
S
S
S
S
S
S
S
S
SS
S
SS
SS
SS
SS
SSS
S
S
S
WW
WW
W
WW
W
W
W
WW
WW
W
WW
WW
W WWW
WWW
W
W
W
W
W
WW
W
W
W
W
W
W W
WWW W
WW
HHHH
H
H
HHHH
HHHH
HH
HHHH H HH
H
HH
HH
HH HH
H
H HH
H H
HHH H H HH
H
Row 2 Row 5
NormalizedNormalized Reflectance Ratio Data Reflectance Ratio Data
Response Plot Sensor ComparisonDiederich Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
105 115 125 135 145
Response Plot Number
No
rma
lized
Re
fle
cta
nc
e R
atio
, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
NormalizedNormalized Reflectance Ratio Data Reflectance Ratio Data
Response Plot Sensor ComparisonCopeland Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
26 36 46 56 66 76 86 96
Response Plot Number
No
rma
lized
Re
fle
cta
nce
Rat
io,
Vis
/NIR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonSchnarre Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
237 247 257 267 277
Response Plot Number
No
rmal
ized
Re
flec
tan
ce
Rat
io,
Vis
/NIR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
NormalizedNormalized Reflectance Ratio Data Reflectance Ratio Data
Within-site, by-sensor Within-site, by-sensor normalization removed much of normalization removed much of the sensor-type variability in the sensor-type variability in many (but not all) casesmany (but not all) cases
In practice, a similar In practice, a similar normalization is accomplished normalization is accomplished using reference strip datausing reference strip data
Well-fertilized as opposed to Well-fertilized as opposed to unfertilizedunfertilized
How well does it work?How well does it work?
Response Plot Sensor ComparisonSchnarre Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
237 247 257 267 277
Response Plot Number
No
rmal
ized
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonCopeland Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
26 36 46 56 66 76 86 96
Response Plot Number
No
rmal
ized
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
Response Plot Sensor ComparisonDiederich Knee-High 2004
Mean-Normalized Data
0.4
0.6
0.8
1
1.2
1.4
1.6
105 115 125 135 145
Response Plot Number
No
rmal
ized
Ref
lect
ance
Rat
io, V
is/N
IR
GreenSeeker Row 2
GreenSeeker Row 5
Crop Circle Row 2
Crop Circle Row 5
N Rec = -200 +250
VisibleNIR
VisibleNIR
Target
Reference
(( )
)N Rec = -200 +250
VisibleNIR
VisibleNIR
Target
Reference
(( )
)
Comparing Sources of VariationComparing Sources of Variation
Sensor Variation
Row-to-row Variation
0.4 0.8 1.2 1.6 2Gre e n Se e ke r N o rm a lize d R a tio , R o w 2
0.4
0.8
1.2
1.6
2
Cro
p C
ircl
e N
orm
aliz
ed
Ra
tio, R
ow
2
P
P
P
PP
P PP
PP P
PP
PP
P
PPP
PP
P
P P
C 1C 1
C 1C 1C 1C 1C 1C 1
C 1C 1
C 1C 1C 1
C 1C 1C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1
C 1
C 1C 1
C 1
C 1C 1C 1C 1
C 1
C 1C 1
C 1C 1C 1
C 1
C 2C 2
C 2C 2
C 2
C 2
C 2C 2C 2C 2
C 2C 2
C 2C 2
C 2
C 2C 2C 2
C 2C 2C 2C 2
C 2C 2
C 2
C 2C 2
C 2C 2C 2C 2
C 2
C 2
C 2C 2
C 2
C 2
C 2
C 2C 2
D
D
DD
DDD
D
D
D
DD
D
D
DD
D
D
D
DD
D
D
D
DD
DDD
D
D
D
DD
D
DD D
DD
D
D
D
D
D
D
BBB
B
BB
B
B
B
B
B
BB
B
B B B BB
BBBBBB
BBBB
B BBBBBBBBB
B
BB
B
B
BBB
B
BB
B
BB BB
BBB
BBB
BB
BB
B
BBBB
BBB B
B
BBB
B
B
BB
BB
B
B
S
S
S
S
S
S
S
S
S
SS
S SS
SS
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SE = 0.13 SE = 0.11
SE = 0.13 SE = 0.10
Comparing Sources of VariationComparing Sources of Variation
0.4 0.8 1.2 1.6 2Gree n See ke r N o rm a lized R a tio , R o w 2
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0.4 0.8 1.2 1.6 2Gre en See ke r N o rm a lized R a tio , R o w 5
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Considerable variability in ratio (or Considerable variability in ratio (or NDVI) readings between sensor typesNDVI) readings between sensor types
Mean normalization removed much of Mean normalization removed much of the variationthe variation
The remaining variation was of similar The remaining variation was of similar magnitude as the variation between magnitude as the variation between corn rows 90 inches apartcorn rows 90 inches apart
How many sensors are needed to How many sensors are needed to “adequately” describe variability?“adequately” describe variability?
More in MO where we can’t seem to get More in MO where we can’t seem to get uniform corn stands?uniform corn stands?
Does Between-Sensor Variability Affect N Rate? Does Between-Sensor Variability Affect N Rate?
476800 476900 477000 477100 477200 477300 4774004349100
4349150
4349200
4349250
476800 476900 477000 477100 477200 477300 4774004349100
4349150
4349200
4349250
R ela tive R eflectance R atio , G reenSeeker Sensor 2
R ela tive R eflectance R atio , C rop C irc le Sensor 3
Does Between-Sensor Variability Affect N Rate? Does Between-Sensor Variability Affect N Rate?
4349150
4349200
4349250
4349150
4349200
4349250
N tech Sensor 2
C rop C ircle Sensor 3
N R ates
1 2 3 4 5 6 7
In this case, there was not much effect when looking at In this case, there was not much effect when looking at large-scale patterns of N rate changeslarge-scale patterns of N rate changes
Does Between-Sensor Variability Affect N Rate? Does Between-Sensor Variability Affect N Rate?
2 4 6
Crop C ircle Rate
2
4
6
Gre
enS
eeke
r R
ate
0 - 3 3 - 6 6 - 9 9 - 12 12 - 15 15 - 18 18 - 21 21 - 24
N Rec = -150 +180
VisibleNIR
VisibleNIR
Target
Reference
(( )
)N Rec = -150 +180
VisibleNIR
VisibleNIR
Target
Reference
(( )
)
2 4 6
2
4
6
Strong relationship between rates from the two sensors, but Strong relationship between rates from the two sensors, but somewhat offset from 1:1 linesomewhat offset from 1:1 line
Does Between-Sensor Variability Affect N Rate? Does Between-Sensor Variability Affect N Rate?
In some fields, GreenSeeker N In some fields, GreenSeeker N rate range was considerably rate range was considerably reduced compared to Crop Circlereduced compared to Crop Circle
Diederich field was a worst-case Diederich field was a worst-case example, perhaps because of a example, perhaps because of a different relationship between the different relationship between the two sensor outputs in low lighttwo sensor outputs in low light
2 4 6
G reenSeeker N R ate
2
4
6
Cro
p C
ircle
N R
ate
0
50
100
150
200
250
300
350
400
450
500
550
D iederich, Sensors 2,3
0.1 0.2 0.3 0.4 0.5 0.6 0.7Gre e n S e e ke r R a tio , R o w 2
0.1
0.2
0.3
0.4
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D
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BBBB
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B
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B BB
B BB BBBB
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BBB B B
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BBB BB BBBBB
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B B B
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S
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SS
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SSSS
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SSS
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WW
WW
W
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W
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W WWW
WWW
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WWW W
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HHHH
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SummarySummary
Sensor “types” are differentSensor “types” are different
So are individual crop rows, at a similar magnitudeSo are individual crop rows, at a similar magnitude
Application rates with the different sensors are similar Application rates with the different sensors are similar in some field conditions, but not in othersin some field conditions, but not in others
Are sensors interchangeable within algorithms, or do Are sensors interchangeable within algorithms, or do we need to consider them as a “package”?we need to consider them as a “package”?