Remote Sensing to Estimate Chlorophyll Concentration Using Multi-Spectral Plant

Reflectance

P. R. Weckler Asst. Professor M. L. Stone Regents ProfessorN. Maness Professor R. Jayasekara Research EngineerC. Jones Research Engineer

Objective

• Estimate Chlorophyll concentration using chlorophyll content and biomass

BiomassionConcentratlChlorophylYieldlChlorophyl *

Sensors• Passive Sensor

- OSU Plant Reflectance sensor

• Active Sensor- Patchen Weedseeker™ PHD 600 Sensor

- Ntech Greenseeker™ Sensor

• Multi-Spectral Camera

Sensing Equipment

Spring, 1999 and 2000 Fall, 2000 and Spring, 2001

Fall, 2002

OSU Reflectance Sensor

OSU Reflectance Sensor

Patchen Weedseeker™ PHD 600 Sensor

OSU Reflectance Sensor

Ntech Greenseeker™

Sensor No camera used Olympus D-360L digital

camera DuncanTech MS3100 multispectral camera

Sensors

Experimental Plots

Vegetation Through Multi-spectral Camera

Spinach Plot with Reflectance Targets

Results

Chlorophyll Content vs. NDVIFall, 2002

y = 0.4738e4.1817x

r2 = 0.9187

0

5

10

15

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

NDVI

Chl

. Con

t, kg

/ha

Biomass vs. NDVIFall, 2002

y = 462.52e4.4826x

R2 = 0.9395

0.0

5000.0

10000.0

15000.0

20000.0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

NDVI

Bio

mas

s, k

g/ha

ResultsNDVI/%VC vs. Chlorophyll Concentration

Fall, 2002

r2 = 0.0263

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

700 750 800 850 900 950

Chlorophyll Concentration, mg/kg

ND

VI/%

VC

NDVI/%VC vs. Chlorophyll Concentration Fall, 2002

r2 = 0.9508Week 4

r2 = 0.6762Week 5

r2 = 0.5473Week 6

r2 = 0.9845Week 7

r2 = 0.6629Week 8

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

700 750 800 850 900 950

Chlorophyll Concentration, mg/kg

ND

VI/%

VC

ResultsStudy NDVI vs

BiomssNDVI vs.

Chlorophyll

Yield

%Vegatative Coverage vs.

Biomass

NDVI/%VC vs. Chlorophyll

Concentration

Spring,1999 0.80 0.80 No camera data

-----------

Spring, 2000 0.81 0.77 No camera data

-----------

Fall, 2000 0.93 0.73 0.73 0.02

Spring, 2001 0.93 0.87 0.98 0.38

Fall, 2002 0.94 0.92 0.85 0.03

Conclusions• The NDVI readings gathered by the handheld sensors and the

multispectral camera were sensitive to changes in plant biomass and plant chlorophyll content in spinach .

• This study reaffirmed the correlation between %VC and dry biomass found by Lukina et al. (1999, 2000) and Ter-Mikaelian and Parker (2000).

• High correlation was observed between the %VC of the spinach as measured with digital imagery and the spinach biomass as measured in the laboratory (r2 = 0.73 to 0.98).

Conclusions

• The findings of Lukina et al. (1999, 2000) and Sembiring (1998) were also supported regarding NDVI readings producing a stronger estimate of chlorophyll content then of chlorophyll concentration.

• NDVI derived from processing images from a multispectral camera correlated well with handheld sensor NDVI.

• The multispectral camera provided accurate %VC information that correlated well with biomass results.

Further Studies

• Low correlations when predicting chlorophyll concentration from estimates of biomass and NDVI may suggest further investigation in following areas:

- canopy stacking

- background interference with sensors

QUESTIONS?

AcknowledgmentsDr. Jerry Brusewitz

Ted KerstenD. Chrz

Bruce BostianOklahoma Vegetable Research

Station,Bixby,Oklahoma