Satellite Imagery for Agronomic Management

Decisions

Winter Wheat, Pond Creek in North Winter Wheat, Pond Creek in North Central Oklahoma April 23, 1998Central Oklahoma April 23, 1998

Variability???

April 23,1998 TM Scene over North Central Oklahoma

ImageImage Processing and NDVI Processing and NDVI ComputationComputation

Clear-sky Thematic Mapper (TM) scenes of north-Clear-sky Thematic Mapper (TM) scenes of north-central Oklahoma, spanning the period 1991 to 1999, central Oklahoma, spanning the period 1991 to 1999, were obtained from Space Imaging with radiometric were obtained from Space Imaging with radiometric and geometric corrections.and geometric corrections.

The TM scenes were chosen so that the satellite The TM scenes were chosen so that the satellite overpasses occurred at or near the heading stage of overpasses occurred at or near the heading stage of winter wheat in the area (mid April to early May).winter wheat in the area (mid April to early May).

Dates and TM scenes used in the study:

• April 4, 1991• May 9, 1992• April 25, 1993• March 27, 1994

• April 2, 1996• April 20, 1997• April 23, 1998• May 12, 1999

OSU Wheat Pasture Research Unit Overlaid on OSU Wheat Pasture Research Unit Overlaid on top of April 23,1998 False Color TM Imagetop of April 23,1998 False Color TM Image

(Green, Red, and NIR bands). (Green, Red, and NIR bands).

Grain wheat

Grazed out wheat

N

OSU Wheat Pasture Research Unit with OSU Wheat Pasture Research Unit with NDVI from April 23,1998 TM Image7NDVI from April 23,1998 TM Image7

0

1000

2000

3000

4000

5000

6000

0.3 0.4 0.5 0.6 0.7 0.8 0.9NDVI

Wh

ea

t Y

ield

(k

g/h

a)

TM 93 (April 25)

TM 97 (April 20)

TM 98 (April 23)

TM 99 (May 12)

Predicted Yield

95% Pred. Lim.

Calibration curve of wheat grain yield as a function of Calibration curve of wheat grain yield as a function of Landsat TM NDVI. Oklahoma State University Wheat Landsat TM NDVI. Oklahoma State University Wheat Pasture Research Unit, Marshall, OKPasture Research Unit, Marshall, OK.

Cherokee

Pond Creek

OSU WPRU

Marshall

Relative Locations of Test Farms and OSU Wheat Pasture Research Unit

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 1000 2000 3000 4000 5000Measured Yield (kg/ha)

Pre

dic

ted

Yie

ld (

kg

/ha

)Cherokee, OK

Pond Creek,OKPond Creek-2,OKMarshall, OK

93

9

96

91

91 96

94

93

97

98

98

92

9394

98

99

91

96

92

96

97 98

Field-average wheat grain yield, as predicted Field-average wheat grain yield, as predicted from NDVI and measured by farmer cooperators.from NDVI and measured by farmer cooperators.

0

1000

2000

3000

4000

5000

6000

0.4 0.5 0.6 0.7 0.8 0.9

Field-Average NDVI

Fie

ld-A

vera

ge

Yie

ld (

kg/h

a)Cherokee, OK

Pond Creek, OK

Pond Creek-2, OK

Marshall, OK

Predicted Yield

95% Pred. Lim.

Field-average wheat yield as a function of field-Field-average wheat yield as a function of field-average NDVI, compared with the OSU WPRU average NDVI, compared with the OSU WPRU prediction equationprediction equation.

Combine Yield Monitor and Satellite Estimated Wheat Yield Maps

Yield Monitor 26.4 bu/acYield Monitor 26.4 bu/ac Satellite Estimate 28.7 bu/acSatellite Estimate 28.7 bu/ac

Normalizing Satellite Estimated Yield

• Normalization tends to remove the effect of weather, disease and other factors on the average yield.

• This minimizes the effect of abnormally high or yields when yield variability is compared between years or averaged over years.

• Yields can be normalized by dividing by the average yield for the field.

Wheat - Landsat TM Image Taken During April to Mid-May Linn Farm, Redrock, OK

19921992 19961996 19981998

Linn Aerial ImageAerial Image vs. Average Yields

TerraceEffects

Linn Farm 7 Year Average Estimated Yield and Coefficient of Variation

PortAPortA

MisclassifiedMisclassified

KirklandBKirklandB

KirklandB2KirklandB2

NorgeC2NorgeC2

NorgeBNorgeB

FloodsFloods

Wheat - Landsat TM Image Taken During April to Mid-May

Kent Farm, Pond Creek, Ok19961996 19981998

Pond Creek, Oklahoma

Dale Silt LoamDale Silt Loam

McLain McLain Silt LoamSilt Loam

Owner Identified SoilOwner Identified Soil

Kent 160, Pond Creek, OK, Normalized Kent 160, Pond Creek, OK, Normalized Estimated Yield and Temporal Coefficient Estimated Yield and Temporal Coefficient

of Variation for Seven Years of Dataof Variation for Seven Years of Data

Water and Water and Hay for CalvesHay for CalvesField DrainageField Drainage

Cherokee, Oklahoma

Reinach Very Reinach Very Fine Sandy Fine Sandy LoamLoam

McLain Silt McLain Silt LoamLoam

Dale Silt Loam - SALINEDale Silt Loam - SALINE

Cherokee, Oklahoma

Hayed for Hayed for Demonstration PlotsDemonstration Plots

Drainage problem from Drainage problem from moldboard dead furrowmoldboard dead furrow

Salt SlickSalt Slick

Hitchcock, OK

< 0.85< 0.85

0.85 – 0.950.85 – 0.95

0.65 – 1.050.65 – 1.05

1.05 – 1.151.05 – 1.15

1.151.15

Field BoundaryField Boundary

Average Normalized YieldAverage Normalized Yield

Hitchcock, Ok – Yield 1992 & 1993

Hitchcock, OK - 1994 & 1996

Hitchcock, OK – 1998 & 1999

Hitchcock, OK

< 0.85< 0.85

0.85 – 0.950.85 – 0.95

0.65 – 1.050.65 – 1.05

1.05 – 1.151.05 – 1.15

1.151.15

Field BoundaryField Boundary

Average Normalized YieldAverage Normalized Yield

Broken out of native grass pasture Broken out of native grass pasture in 10 ac increments in the 1970’sin 10 ac increments in the 1970’s

Farm since homesteadedFarm since homesteaded

Disease Effect on Estimated

Yield -Enid, OK

5% Set-Aside Ground5% Set-Aside Ground

ChisholmChisholm

21802180

Carrier, OK – 1999 Yield

Hail DamageHail Damage

Tonkawa, OK

Sprayed with Sprayed with Metribuzin for Metribuzin for CheatCheat

Not sprayed for Not sprayed for cheatcheat

Area was Area was intensively intensively grazed by 105 grazed by 105 calves. Wheat calves. Wheat yield was about yield was about 3 times greater 3 times greater than estimatedthan estimatedSaline SoilSaline Soil

Tonkawa, OK

What may be gained by even higher What may be gained by even higher resolution sensing?resolution sensing?

25 m Resolution (Re-sampled) 25 m Resolution (Re-sampled) Landsat TMLandsat TM

1m Resolution NDVI1m Resolution NDVI

Conclusions

• Satellite imagery can be used to predict yields.

• Normalized estimated yield can be used for management decisions:– Define average relative yield– Identify regions of high and low yield whose

cause changes slowly over time• Drainage• Soil type• Organic matter• pH

Conclusions• Images can be used to define

management zones for the purpose of managing these variables.

• Imagery can complement yield monitor data or when yield data are not available can serve as a surrogate.

• Currently, Landsat TM images are the only source of historical data for the entire United States, and, despite the coarse resolution provides, a means to begin managing less than field size areas.

30 by 30 m

Sensing and Treatment Resolution

1 m by 1 m