Transcript CIMMYT-OSU System: Improving N Recommendations

CIMMYT-OSU System: Improving
N Recommendations
Precision Sensing Extension Workshop
Cody Daft
Daniel Edmonds
January 8, 2008
Fundamentals of Light
• Light = Energy
(radiant energy)
– Readily converted to heat
• Light shining on a surface heats the surface
• Heat = energy
• Light = Electro-magnetic phenomena
– Has the characteristics of electromagnetic waves
(eg. radio waves)
– Also behaves like particles (e.g.. photons)
Visual reception of color
• Receptors in our eyes are tuned to particular photon
energies (hn)
• Discrimination of color depends on a mix of different
receptors
• Visual sensitivity is typically from wavelengths of
~350nm (violet) to ~760nm (red)
Wavelength
400 nm
500 nm
700 nm
Primary and secondary absorbers in
plants
• Primary
– Chlorophyll-a
– Chlorophyll-b
• Secondary
– Carotenoids
– Phycobilins
– Anthocyanins
Radiation Energy Balance
• Incoming radiation interacts with an object
and may follow three exit paths:
Incident
Reflected
– Reflection
– Absorption
– Transmission
Absorbed
Transmitted
Nature of absorption by the
atmosphere
Transmitted
Reflected
Incident
Absorbed
Earth's
surface
Atmosphere
Radiant energy balance must
be computed for each
component of the atmosphere
and for each wavelength
to estimate the radiation
incident on the earth's surface
Visible
Near Infrared
Reflectance (%)
0.5
0.25
Plant Reflectance
0.00
450 500 550 600 650 700
750 800
850 900
950 1000 1050 1100
1150
Spectral response to Nitrogen
1
0.9
Winter Wheat at Feekes 5 in potted soil
0.8
Reflectance
0.7
0.6
0.5
0 lb Nitrogen
0.4
100 lb Nitrogen
0.3
0.2
0.1
0
400
500
600
Wavelength, nm
700
800
Soil and crop reflectance
0.6
17 Corn
73 Cotton
9 Sunflower
Fractional Reflectance
0.5
27 Soybeans
0.4
25 Potatoes
0.3
43 Soils
0.2
P. S. Thenkabail
R. B. Smith
E. De Pauw
Yale Center for Earth Observation
0.1
0
300
400
500
600
700
800
Wavelength (nm)
900
1000
1100
Reflectance Indices
Based on ratios of Red and NIR Reflectance
Red Reflectance:
Rred
red
= Rred / Ired
NIR Reflectance:
Ired
nir
= Rred / Ired
Index:
 nir   red
NDVI 
 nir   red
Reflectance is primarily
a function of target
Sensor-Based Top-Dress Fertilizer Concept:
• Plant spectral reflectance in red and NIR
bands are used to measure nitrogen uptake
and estimate crop yield
• Plant is an indicator of availability of
nutrients, previous environment, insect
damage, etc.
• Application rate determined based on
estimated yield and response index.
GreenSeekerTM N-Fertilizer Handheld
Optical Sensor
• Optically measures plant biomass, total nitrogen in
the crop, and plant stress
• Can sample scan a wheat field (or other crop)
• Data can be used to calculated response index for
added nitrogen fertilizer
Questions…. Answers
• Do N Rates Vary from one year to the next in
the same Field?
• If they do, why?
• Can N Rates be Adjusted based on Predicted
Yield?
• Can the Responsiveness to N be Predicted?
• How does the new system work (based on
predicted yield and RI)?
Optimum N Rate
(Grain N Uptake Max Yield – Grain N Uptake Check)/0.50
Optimum N Rate, lb/ac
200
180
RCRS, Mead NE, 1960-1983
160
Optimum N Rate
Avg. 81 lb N/ac +/- 38
Long-Term Corn Experiment
R.A. Olson, UNL
Max Yield
Avg. 145 bu/ac +/- 19
140
120
100
80
60
40
20
0
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983
“After the FACT” N Rate required for “MAX Yields” Ranged from 25 to 165 lbs N/ac
Solutions
Technological Requirement
•
•
•
Nitrogen Rich Strip
N Rich Strips, Ramped N
Sensor Based N Rate Calculator
NONE
NONE
Key Components of Sensor Based
Technology
• Response Index: (RI)
• Yield Potential with no added N (YP0)
• Yield Potential with added N (YPN)
• In Season Estimate of Yield (INSEY)
Can the Response Index (RI) be
predicted from MID-Season NDVI
readings?
In-Season Response Index (RINDVI)
Non-N Limiting
RI NDVI 
Farmer Practice
NDVI non N limiting
NDVI field rate
0.7

 1.46
0.5
1. Can Yield Potential (similar to “yield
goals”) be Predicted MID-SEASON?
Predicting Yield
Potential in Corn
ANSWER: YES!
Look at the Dashed
Line which is 30%
plus the yield
prediction
NDVI, V8 to V10

INSEY
Days from planting to sensing
20
18
16
NOTE: The objective is to predict
Grain yield, Mg ha -1
“yield potential” not yield.
104-day (2003)
20 Locations, 2002-2005
Hybrid Corn, Mexico, Nebraska, Iowa,
Oklahoma, Virginia, Ohio
V8-V10 (44 to 69 days)
107-day (2003)
111-day (2003)
99-day (2004)
113-day (2004)
14
105-day (2002)
109-day (2002)
1.7916
y = 19583x
R2 = 0.71
12
113-day (2002)
113-day (OFIT)
10
108-day (OFIT)
Efaw (2003)
8
LCB (2003)
Efaw (2004)
6
LCB 2004
Mexico (2002)
4
Shelton (2004)
CORN
2
0
0.002
0.004
0.006
0.008
0.01
INSEY
0.012
0.014
Ames (2004)
Ohio
0.016
0.018
N Fertilization Algorithm
3
1
Yield Prediction
2
Response Index (N Rich Strip Compared
to the Farmer Practice)
3
Yield obtainable with added N (YPN = RI *
YP0)
4
Fertilizer Rate= (GNUPYPN-GNUPYP0)/0.6
2
4
The efficiency factor of 0.6 can
change depending on the crop
and production circumstances
1
RI-NFOA
YPN=YP0 * RI
YPN YPN YP0
Grain yield
YPMAX
INSEY (NDVI/days from planting to sensing)
Nf = (YP0*RI) – YP0))/Ef
The mechanics of how N rates are computed are really very simple
1. Yield potential is predicted without N
2. The yield achievable with added N is #1 times the RI
3. Grain N uptake for #2 minus #1 = Predicted Additional N Need
4. Fertilizer Rate = #3/ efficiency factor (usually 0.5 to 0.7)
Nitrogen Fertilizer Optimization
Algorithm
The development of an algorithm directly
related to a specific region is important to
make accurate nitrogen fertilizer
recommendations for that area.