Comparing Different Remote Sensing Approaches for Early Season Nitrogen Deficiency Detection in Corn NUE Workshop: Improving NUE using Crop Sensing, Waseca,

Comparing Different Remote Sensing Approaches for Early Season Nitrogen Deficiency Detection in Corn

NUE Workshop: Improving NUE using Crop Sensing, Waseca, MN

Yuxin Miao1, David J. Mulla1, Gyles W. Randall2, Jeff A. Vetsch2, and Roxana Vintila3

1. Precision Agriculture Center, University of Minnesota.2. Southern Research and Outreach Center, University of Minnesota.3. Research Institute of Soil Science and Agrochemistry (ICPA), Romania.

Different Sensing Approaches for Precision N Management

Chlorophyll Meter:

SPAD 502

GreenSeeker:

CropScan Multispectral Radiometer:

Aerial or Satellite -based Remote Sensing:Aerial or Satellite -based Remote Sensing:

High spatial resolution remote sensing images are potentially cheaper, more efficient and more spatially detailed than chlorophyll meter or

other ground-based hand-held sensors.

(Image from http://www.eoc.csiro.au/hswww/Overview.htm)

Hyperspectral Remote Sensing

Different Sensing Approaches for Precision N Management

Objectives

To compare the effectiveness of different sensing To compare the effectiveness of different sensing approaches to monitor early season corn plant N status approaches to monitor early season corn plant N status

and detect N deficiency:and detect N deficiency:

Identify hyperspectral bands (wavelengths), band Identify hyperspectral bands (wavelengths), band ratios and vegetation indices that are sensitive to early ratios and vegetation indices that are sensitive to early season corn plant N status; season corn plant N status;

SPAD Meter; GreenSeeker; CropScan multispectral radiometer; Aerial hyperspectral remote sensing; and, Aerial multispectral remote sensing (simulated).

Materials and Methods – Study Sites

Field 1: Corn-Soybean Rotation

Field 2: Corn-Corn Rotation

Materials and Methods – N Treatments

Field 1, Corn-Soybean Rotation 3 x 15.2 m

Materials and Methods – N Treatments

Field 2, Corn-Corn Rotation

Materials and Methods – Data Collection

N Concentration:

V9: Whole plant sampling, 10 plants: N concentration, biomass; R1: Ear leaf, 10 leaves; Harvest: grain and stover.

SPAD Meter:

F1: V9, V11, R1, and R3; F2: V7, V9-10, V12, R1, R3 Collected 30 readings from each plot.

GreenSeeker:

F1: V9 and V11; F2: V8, V9-10, V11-V12 and V12.

CropScan Multispectral Radiometer:

V6 and V9; About 50 cm above the canopy, three samples each plot.

Materials and Methods – Data Collection Aerial Hyperspectral Remote Sensing:

AISA-Eagle (AE) Hyperspectral Imager 61 bands from 392 – 982 nm, at 8.76 – 9.63nm;

At 0.75 m spatial resolution;

V9, R1, R2 and R4;

Pixels of the central two rows in each plot were averaged;

Simulated Multispectral Remote Sensing:

Landsat ETM+ sensor’s four broad bands: Blue: 450-515nm; Green: 525-605nm; Red: 630-690 nm; NIR: 775-900nm.

Materials and Methods – Band Combinations Simple Ratio (SR)

RatioRatio DefinitionDefinition ReferenceReference

Green IndexGreen Index

Zarco-Tejada & Miller (ZTM)Zarco-Tejada & Miller (ZTM)

PSSRaPSSRa

PSSRbPSSRb

PSSRcPSSRc

SPRISPRI

SR1SR1

SR2SR2

SR3SR3

SR4SR4

SR5SR5

SR6SR6

SR7SR7

RR554554//R677R677

RR750750/R/R710710

RR800800/R/R680680

RR800800/R/R635635

RR800800/R/R470470

RR430430/R/R680680

NIR/Red = RNIR/Red = R801801/R/R670670

NIR/Green=RNIR/Green=R800800/R/R550550

RR700700/R/R670670

RR740740/R/R720720

RR675675/(R/(R700700 x R x R650650))

RR672672/(R/(R550550 x R x R708708))

RR860860/(R/(R550550 x R x R708708))

Smith et al., 1995Smith et al., 1995

Zarco-Tejada et al., 2001Zarco-Tejada et al., 2001

Blackburn, 1998Blackburn, 1998



Penuelas et al., 1994Penuelas et al., 1994

Daughtry et al., 2000Daughtry et al., 2000

Buschman and Nagel, 1993Buschman and Nagel, 1993

McMurtrey et al., 1994McMurtrey et al., 1994

Vogelman et al., 1993Vogelman et al., 1993

Chappelle et al., 1992Chappelle et al., 1992

Datt, 1998Datt, 1998


Materials and Methods – Band Combinations

IndexIndex DefinitionDefinition ReferenceReference

DI1DI1

DVIDVI

NDVINDVI

Green NDVIGreen NDVI

PSNDbPSNDb

PSNDcPSNDc

NPCINPCI

NPQINPQI

SIPISIPI

mND705mND705

mSR705mSR705

NDI1NDI1

NDI2NDI2

NDI3NDI3

RR800800-R-R550550

RR800800-R-R680680

(R(R800800-R-R680680)/(R)/(R800800+R+R680680))

(R(R801801-R-R550550)/(R)/(R800800+R+R550550))

(R(R800800-R-R635635)/(R)/(R800800+R+R635635))

(R(R800800-R-R470470)/(R)/(R800800+R+R470470))

(R(R680680-R-R430430)/(R)/(R680680+R+R430430))

(R(R415415-R-R435435)/(R)/(R415415+R+R435435))

(R(R800800-R-R445445)/(R)/(R800800-R-R680680))

(R(R750750-R-R705705)/(R)/(R750750+R+R705705-2 x R-2 x R445445))

(R(R750750-R-R445445)/(R)/(R705705-R-R445445))

(R(R780780-R-R710710)/(R)/(R780780-R-R680680))

(R(R850850-R-R710710)/(R)/(R850850-R-R680680))

(R(R734734-R-R747747)/(R)/(R715715+R+R726726))

Buschman and Nagel, 1993Buschman and Nagel, 1993

Jordan, 1969Jordan, 1969

Lichtenthaler et al., 1996Lichtenthaler et al., 1996





Barnes et al., 1992Barnes et al., 1992


Sims and Gamon, 2002Sims and Gamon, 2002

Sims and Gamon, 2002Sims and Gamon, 2002



Vogelman et al., 1993Vogelman et al., 1993

Difference Index (DI) and Normalized Difference Index (NDI)

Integrated Index (II)

Materials and Methods – Band Combinations

IndexIndex DefinitionDefinition ReferenceReference

MCARIMCARI

TCARITCARI

OSAVIOSAVI

TCAVI/OSAVITCAVI/OSAVI

TVITVI

MCARI/OSAVIMCARI/OSAVI

RDVIRDVI

MSRMSR

MSAVIMSAVI

MTVIMTVI

[(R[(R700700-R-R670670)-0.2x(R)-0.2x(R700700-R-R550550)](R)](R700/700/RR670670))

3x[(R3x[(R700700-R-R670670)-0.2x(R)-0.2x(R700700-R-R550550)(R)(R700700/R/R670670)])]

(1+0.16)(R(1+0.16)(R800800-R-R670670)/(R)/(R800800+R+R670670+0.16)+0.16)

0.5x[120x(R0.5x[120x(R750750-R-R550550)-200x(R)-200x(R670670-R-R550550)])]

(R(R800800-R-R670670)/SQRT(R)/SQRT(R800800+R+R670670))

(R(R800800/R/R670670-1)/SQRT(R-1)/SQRT(R800800/R/R670670+1)+1)

0.5x[2xR0.5x[2xR800800+1-SQRT((2xR+1-SQRT((2xR800800+1)+1)22-8x(R-8x(R800800-R-R670670))]))]

1.2x[1.2x(R1.2x[1.2x(R800800-R-R550550)-2.5x(R)-2.5x(R670670-R-R550550)])]


Haboudane et al., 2002Haboudane et al., 2002

Rondeaux et al., 1996Rondeaux et al., 1996


Broge and Leblanc, 2000Broge and Leblanc, 2000

Zarco-Tejada et al., 2004Zarco-Tejada et al., 2004

Rougean and Breon, 1995Rougean and Breon, 1995

Chen, 1996Chen, 1996

Qi et al., 1994Qi et al., 1994


Broad Band Combinations

NIR/Green; NIR/Red; Blue NDVI; Green NDVI; Red NDVI.

Materials and Methods – Analysis Correlation analysis;

Multiple linear regression;

Nitrogen Sufficiency Index (NSI)

NSI = Yield, Plant N, SPAD, or index

Reference valuex 100%

NSI of Plant N Concentration as standard

F1: the average of the highest two preplant N rates: 168 and 202 kg ha-1.

F2: 224 kg ha-1.

Results and Discussion: Plant N Variability

24.9

36.1

31.9

CV = 9.33%

18.7

34

28.2

CV = 14.06%

202 kg ha-1 224 kg ha-1

0

10

20

30

40

50

60

70

400 800 1200 1600 2000

Wavelength (nm)

Ref

lect

ance

(%)

0 kg/ha

45 kg/ha

179 kg/ha

224 kg/ha

0

5

10

15

20

25

30

35

40

45

400 500 600 700 800 900 1000Wavelength (nm)

Ref

lect

ance

(%

)

0 kg/ha

45 kg/ha

179 kg/ha

224 kg/ha

Results and Discussion: Impact of N Rate on Reflectance

CropScan MSR

Hyperspectral RS

Results and Discussion: Sensitive Wavelengths

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

450 650 850 1050 1250 1450 1650 1850

Wavelength (nm)

Cor

rela

tion

Coe

ffic

ient

F1

F2

Correlation between plant N concentration and CropScan reflectance at V9

560-710nm

760-1000nm

Results and Discussion: Sensitive Wavelengths

Correlation between plant N concentration and hyperspectral reflectance at V9

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

350 450 550 650 750 850 950

Wavelength (nm)

Cor

rela

tion

Coe

ffic

ient F1

F2

554 and 563nm 695nm

742-982nm

Results and Discussion: Sensitive Indices

GNDVI:

Field 1 Field 2

CropScan: 0.51 0.72NIR/Green: R800/R550 0.50 0.71

NDI2NDI2 0.71

Hyperspectral: NDI1NDI1 0.780.47

0.39

NDI2NDI2 0.790.41

SPAD Meter: 0.58 0.85

GreenSeeker NDVI: 0.26 0.49

Simulated Landsat ETM+: GNDVI: 0.31 0.68

Correlation with Plant N Concentrations at V9

Correlation Coefficient

CropScan: 6 (F1)/5(F2) bands 0.77 0.79

5 (F1)/4(F2) Indices 0.67 0.79

Hyperspectral: 4 bands 0.73 0.89

Field 1 Field 2

SPAD Meter: 0.58 0.85

4 (F1)/3(F2)indices 0.66 0.88

3 bands 0.56 0.892 indices 0.57 0.88

Simulated Landsat ETM+:

Results and Discussion: Multiple Regression

Results and Discussion: N Sufficiency Index

556065707580859095

100

0 50 100 150 200 250

Nitrogen Rate (kg ha-1)

NSI

(%)

N Content(V9)

Yield

70

75

80

85

90

95

100

105

0 50 100 150 200 250


NSI

(%)

N Content (V9)

Yield

70

75

80

85

90

95

100

105

0 50 100 150 200 250


NSI

(%)

N Content (V9)

Yield

Results and Discussion: N Deficiency DetectionTreatment Level, Field 1, Corn-Soybean Rotation

ID

123456789101112131415

Plant N SPAD GS GCropScan

TVIHyper

NIR/GLandsat

Yield

Results and Discussion: N Deficiency DetectionTreatment Level, Field 2

ID Plant N SPAD GS SR7CropScan

DI1Hyper

NIRLandsat

1234

567

89

1011121314

Yield

Results and Discussion: N Deficiency DetectionPlot Level, Field 1, Corn-Soybean Rotation

Deficient Plots Sufficient Plots DS SD Overall Accuracy (%)

Plant N Content 34 26 0 0 100

SPAD Meter 3 26 0 0 48

GreenSeeker 15 17 19 9 53

CropScan: MCARI 22 14 12 12 60

Hyperspectral: MCARI 25 11 9 15 60

Landsat ETM+: Green 17 15 17 11 53

(35)

(47)

(60)

(55)

(62)

(44) (16)

Results and Discussion: N Deficiency Detection

Plot Level, Field 2, Corn-Corn Rotation

Deficient Plots Sufficient Plots DS SD Total Accuracy (%)

Plant N Content 29 27 0 0 100

SPAD Meter 21 25 8 2 82

GreenSeeker 10 26 19 1 64

CropScan: TCARI/OSAVI 18 22 11 5 71

Hyperspectral: SR7 21 22 8 5 77

Landsat ETM+: NIR/Green 17 20 12 7 66

(71)

(43)

(59)

(61)

(57)

(46) (10)

0

5

10

15

20

25

30

35

40

45

400 500 600 700 800 900 1000Wavelength (nm)

Ref

lect

ance

(%

)

0 kg/ha

45 kg/ha

179 kg/ha

224 kg/ha

Results and Discussion: Promising Indices

Normalized Difference Index 2 (NDI2)

RR850850-R-R710710

RR850850-R-R680680

NDI2 =

Results and Discussion: Promising Indices

Simple Ratio 7 RR860860

RR550550 x R x R708708

SR7 =

0

5

10

15

20

25

30

35

40

45

400 500 600 700 800 900 1000Wavelength (nm)

Ref

lect

ance

(%

)

0 kg/ha

45 kg/ha

179 kg/ha

224 kg/ha

Conclusions

The sensors performed better in corn-corn rotation field than in corn-soybean rotation field at V9;

The NIR region was most sensitive to N deficiency at V9;

Reflectance at around 550-560 nm, 696 nm, and NIR region was highly correlated with corn plant N concentration at V9;

SPAD meter readings and GreenSeeker NDVI data had the highest and lowest correlation coefficients with corn plant N concentration, respectively;

Hyperspectral aerial remote sensing has a good potential to monitor spatial corn N variation, and identify N deficiency at V9, especially in corn-corn rotation fields;

SR7 and NDI2 were promising indices for N deficiency identification and deserve further testing.

Documents

Comparing Different Remote Sensing Approaches for Early Season Nitrogen Deficiency Detection in Corn NUE Workshop: Improving NUE using Crop Sensing, Waseca,