Integrating Remote Sensing in Precision Agriculture:

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Integrating Remote Sensing in Precision
Agriculture Lessons Learned and New Directions
Jim Schepers USDA-ARS Agronomy and Horticulture
Department University of Nebraska
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Satellites
Clouds Timeliness Turn Around Resolution
Clouds Timeliness
Platforms
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Spectral Opportunities
70 60 50 40 30 20 10 0


Photosynthesis
Reflectance ()
400 500 600 700 800 900 1000
Wavelength (nm)
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Spectral Opportunities
70 60 50 40 30 20 10 0


Bare Soil
Reflectance ()
400 500 600 700 800 900 1000
Wavelength (nm)
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Computer Generated Management Zones
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Sensor-based mapping
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Data Collection
Reality
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Regrouping
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Soil-based N Management
After Planting
Bare Soil Image
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Computer Generated Management Zones
Incorporating. . .
Bare Soil Image Elevation Slope EM-38
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Spectral Options
70 60 50 40 30 20 10 0


Color Film
Reflectance ()
400 500 600 700 800 900 1000
Wavelength (nm)
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Color IR
Soybean
Hail damage
Sprayer problems
Cultivation in progress
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UniformityConcerns (May Turn Into Huge Yield
Concerns)
End-gun OFF
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IrrigationDesign Flaws
Nozzle in canopy
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Irrigation Design Flaws
Corner unit ON
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September 1, 2003
1-foot resolution
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September 1, 2003
1-foot resolution
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Leaf Anatomy Spectral Interaction
Chlorophyll
Palisade Cells
Spongy Mesophyll
Lower Epidermis
Stoma
Air Space
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70 60 50 40 30 20 10 0
Young Plant
Reflectance ()
Bare Soil
400 500 600 700 800 900 1000
Wavelength (nm)
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70 60 50 40 30 20 10 0
Healthy Plant
Reflectance ()
Bare Soil
400 500 600 700 800 900 1000
Wavelength (nm)
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September 1, 2003
1-foot resolution
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Normalized Difference Vegetation Index
70 60 50 40 30 20 10 0


NDVI (NIR Red) / (NIR Red)

Near Infra-Red
Reflectance ()
GNDVI (NIR Green) / (NIR Green)
400 500 600 700 800 900 1000
Wavelength (nm)
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Sensitivity of Vegetation Indices To Various
Chlorophyll Levels
Adapted From Gitelson et al. (1996)
LAI gt2.0
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Mosaic Approach to Variable Rate N
Maize
Imagery during grain fill (yield map
proxy) Bare soil image (estimate
OM) Residual N (field average)
Spatial yield goal
Spatial mineralization ??
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Correlation Coefficient
12-bit aircraft data 24 x 50 plots 1 spatial
resolution
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Green NDVI vs N Rate over Time
Irrigated Corn
kg N/ha
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Field Calibration
Direction of travel
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Sufficiency Index (SI)
Unknown Reference
Response Index (RI)
Reference Unknown
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Making In-Season nitrogen fertilizer
recommendations
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?
?
What information is needed ?
Are all approaches equally viable ?
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Building Blocks of N Recommendations
Field-scale yield goal provided by
producer Variable yield goal based on maps (MZ,
etc.) Predicted yield based on crop vigor
Dynamics of crop growth
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Dry Matter (Mg/ha)
?
GGD
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Irrigated Corn
What we know Weather in July and August has a
strong influence on yield. How can yield
estimates compensate for weather?
N Uptake
Dry Matter
Total N Uptake (kg/ha)
Dry Matter (Mg/ha)
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Relative Yield
Dry Matter (Mg/ha)
Mosaic Approach
GGD
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What we know about corn ? ? ?
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50 Sun-Screen
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V6 V8 Avoid all stresses
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Influence of Seedling Emergence And Spacing on
Corn Yield
Planter Speed
Tillage
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Effect of Plant Spacing On . . . . .
Leaf N Concentration SPAD Readings Yield
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24,000 plants/acre
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Conclusion Root exploration is extensive
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Conclusion For a given N rate, photosynthesis is
proportionate to light interception
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Conclusion For a given N rate, grain is
proportionate to light interception, which is
proportionate to distance between plants
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Extrapolated Yield Based on By-Plant Grain
Yield (bu/acre)
Conclusion Roots and leaves of closely spaced
plants explore considerably more area than is
proportionate to the allocated average distance
between adjacent plants
Average Distance (inches)
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Extrapolated Yield Based on By-Plant Grain
Yield (bu/acre)
Average Distance (inches)
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By-Plant Yield Variability
weighed grain from individual plants from 20
long sections of 10 rows from different
management zones and N treatments
Nobody told these plants that they couldnt share
above-ground spaces. They also share below-ground
living quarters.
Where do the nutrients come from that contribute
to yield? How about the assimilation of
carbohydrates?
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What are the causes of different ear
sizes? Emergence date Plant spacing Nutrients
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What is the appropriate spatial resolution for N
management ?
Field Strip Management Zone Few Plants
What is possible ? What is practical ?
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Managing N According To - - - -
Macro-heterogeneity
Landscape features
Management zones
Micro-heterogeneity
Individual or Group of Plants
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Yield
Relative SPAD
kg N/ha
GDD
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Yield
Relative SPAD
kg N/ha
GDD
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Yield
V6
V12
Relative SPAD
kg N/ha
GDD
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Irrigated Corn
What will work for producers? Risk Equipment Econo
mics Labor
N Uptake
Dry Matter
Total N Uptake (kg/ha)
Dry Matter (Mg/ha)
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Decision Aid Development
In-Season N Management
Calibration
Algorithm
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Congratulations . . .
You Survived !!!!
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Thank You
Jim Schepers 402-472-1513 jschepers1_at_unl.edu