Transcript Sensing Grain Protein From the Combine

On-The-Go Grain Protein
Monitors
Dan Long
USDA-ARS Pendleton, OR
2/20/2007
Questions

What kinds of sensors are there?

How do they work?

How well do they work?

What can I do with the information?
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Near Infrared Analysis

Typical molecules include CH, OH and
NH and their related chemistries
regarding constituents (protein, fat, oil,
glycerin, water, methanol).
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Principle of Operation
Transmittance
Detector
NIR Radiation
Light Source
Sample Cell
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Principle of Operation
Reflectance
NIR Radiation
Light Source
Grain Stream
Detector
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Mode of Operation
On-Line
grain stream
sensor
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Mode of Operation
In-Line
grain stream
sensor
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Zeltex AccuHarvest
Handheld Computer
Inlet
Sampling
Device
Outlet
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Zeltex AccuHarvest
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NIR Technology Cropscan 2000G
spectrometer
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fiber optic
cable
inlet
sampling
device
fiber optic
cable
outlet
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inlet
sampling
device
fiber optic
cable
outlet
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Dsquared Development
ProSpectra™
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AccuHarvest Field Tests
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AccuHarvest Vs. Reference Protein
SEP=0.49%
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Map Comparison
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Cropscan 2000G
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Cropscan
Vs.
Reference
Protein
19
Cropscan Protein (%)
20
y = 0.8317x + 4.7154
R2 = 0.5534
18
17
16
SEP=0.66%
15
14
y=x
13
R2 = 0.99
SEP = 0.19%
12
11
10
10
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11
12
13
14
15
16
Reference HRSW Protein (%)
17
18
19
Map Comparison
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Cropscan Protein (%)
Overall
Precision
R2 = 0.9
14
y = 1.07x - 1.25
SEP=0.9
13
R2 = 0.71
12
SEP=0.9%
11
10
9
8
7
6
6
7
8
9
10 11 12 13 14
Reference SWW Protein (%)
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ProSpectra™
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Continuous Wheat
No-Till
Wheat-Fallow
Wheat-Fallow
Pea-Wheat-Fallow
No-Till
Volunteer
Wheat
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Nutrient Management Opportunities
Verify protein response to applied N
 Identify N management zones
 Evaluate N sufficiency for yield
 Estimate N removed in grain
 Estimate N required to reach protein level
 Estimate straw yield

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Verify Protein Response
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Identify Management Zones
ZONE
1999
H MH M ML L
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Ave. Protein (1997) & Soil N
(1999)
ZONE
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PROTEIN (1997)
SOIL N (1999)
%
lb/ac
Low
11.4
37
M. Low
12.6
43
Mod.
13.6
76
M. High
14.3
53
High
15.2
116
Map Comparison of Differing
Years
1997
1999
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Evaluate N Sufficiency For Yield
Critical
Protein
Wheat
Class
Location
Study
11.5
HW
Colorado
Goos et al. 1984
13.2
HRS
Montana
Engel et al. 1999
12.5
HRW
Montana
Engel et al. 2005
12.8
HRS
Sask.
Seles & Zentner 2001
8.8
SWW
Oregon
Glenn et al. 1988
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Where Was N Deficient for
Yield?
30 bu/a
14% protein
60 bu/a
11% protein
knoll
bottom
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Yield Map Interpretation
deficient
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sufficient
N Management Strategy

N Removed = (YieldProtein)(1005.7)

N Deficit = (Target Level - Current Level) 
N Unit Equivalent

Site Specific Management Guideline #24
(http://www.ppi-far.org/ssmg)
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Precision N Management
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Spatially Variable Vs. Uniform
90
70
50
30
5
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Grain Protein Response
Uniform
Fertility Area N rate Applied
Variable
Protein N rate
Applied
Protein
Low
6.5
30
195 13.31.5
90
585 15.60.6
M. low
21
30
630 13.41.7
70
1470 16.60.7
Mod.
48
30
1440 15.21.3
50
2400 16.41.1
M. high
98
30
2940 15.71.5
30
2940 16.01.4
High
89
30
2670 16.71.1
5
445 15.81.5
Totals
263
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7875
7840
Water-N-Genotype Gradient
3 years – HR Spring Wheat
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7.3”
11.5”
16.6”
18 bu/ac
39 bu/ac
65 bu/ac
11 0
R e la tive yie ld , %
100
90
80
70
60
50
40
c ritic a l le ve l
30
10
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12
14
16
G ra in p ro te in , %
18
20
Fertilizer N Equivalent
20
19
Grain Protein (%)
Grain Protein (%)
18
12-22
lb +N12.98(X)
Y = 0.081
17
16
15
14
13
Low Moisture (7.3 in)
Normal Moisture (11.5 in)
High Moisture (16.5 in)
15% Protein Level
12
11
10
0
20
40
60
80
100
120
140
-1
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Applied N (kg
ha ac-1))
Applied
N (lb
160
180
200
220
Predicted straw yield, lb/ac
Straw Yield Prediction
6000
Y = 0.783 X + 776
5000
Std error pred = 364
4000
3000
2000
Model factors
grain yield
1000
grain protein
0
0
1000
2000
3000
4000
5000
Observed straw yield, lb/ac
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6000
Limitations of Technology

Precision and bias
– Vibration
– Foreign material
– Wear and build up
– Field to field differences in grain

Transfer of calibration
– Each instrument is slightly different
– Thermal stability
– Harvested grain differs from that used for
calibration
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Protein Indices are Imperfect



Climate: may not be suited for rainfall regimes
where yield potential exceeds 60 bu/ac
Genotype: some cultivars do not experience yield
loss when protein is below the critical level (Fowler,
2003)
Weather-soil interactions:
– Influences mineralizable N and plant N uptake
– Excess N leads to yield reductions under severe drought
– Protein is abnormally elevated under severe drought (Seles
and Zentner, 2001)
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Towards Improved PNM

Previous season
– Grain yield and protein sensing
– Assess N sufficiency
– Identify management zones
– Retrospective assessment
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Towards Improved PNM

Pre-season
– Soil testing/soil sensing approaches
– Model potentially mineralizable N
– Proactive assessment

In-season
– Proximal/remote crop sensing
– SPAD chlorophyll/tissue testing
– Real-time assessment
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