Field Data Analysis: Emily L. Sayles Student Airborne Research Program 12 August 2009

Field Data Analysis Emily L. Sayles Student Airborne Research Program 12 August 2009

Photo: Shawn Kefauver

Overview •2 Sites in California’s Central Valley •Almond Orchard in Kern County •Cotton Field in Kings County •Collection of field data from July 2025, 2009 •Two DC-8 research flights over sites, July 22 and 24, 2009 •Purpose of collecting ground data: •Calibration of MASTER data •Inputs for calculations of evapotranspiration, etc.

Photo: SARP website

Relevant Terms and Indices Leaf Area Index (LAI) •Leaf Area/Ground Area Photosynthetically Active •Dimensionless value Radiation (PAR) Apogee Instruments, •Range of light between 400-700 nm

Chlorophyll Content Index (CCI)

Inc.

•Measures optical transmission through a leaf •ratio of percent transmission at 931 nm to

SPAD

Apogee Instruments,

•Minolta’s Special Products Analysis Division •Measures difference in optical density through a leaf

Instruments Used in the Field LAI Readings

Hemispherical Photography

LiCOR LAI-2000 •One above canopy (open sky) •One below canopy •Twilight conditions needed •Concentric ring sensors measure canopy light

AccuPAR •One above canopy (open sky) •One below canopy •No restrictions

Instruments Used in the Field SPAD Measurements

Photo: Shawn Kefauver

Konica Minolta Spadmeter •2 sides of the tree (east, west) •3 levels of canopy (low, mid, high) •4 leaves per side/canopy location •6 readings per leaf •Average to get one value

Summary of Field Data Collected and Analyzed

Analysis of Hemispherical Photographs Threshold Value

Analysis of Hemispherical Photographs

•Highly subjective process •Concern for consistency •2 HemiView analyses per photo

•Average LAI per photo •Average LAI per

Agreement Between LAI Measurement Techniques LAI-2000 and Hemispherical Photographs

•6 almond trees measured using both methods •Half show good agreement, half show poor agreement

Correlation Between Chlorophyll Content and Leaf Area Index Almond Trees

•Expected monotonic relationship between CCI and LAI •Data from photos show pretty well-defined

Correlation Between Chlorophyll Content and Leaf Area Index Cotton Field

•Wide scattering of data •No apparent trend

Nitrogen Treatment and LAI, CCI Almond Trees

Wide LAI and CCI ranges for one nitrogen treatment

Summary of Field Data Analysis •Limited data sets with little overlap •Correlation between LAI methods cannot be asserted •Good agreement with expected results for almond LAI vs. CCI using photos •Rough correlation between almond LAI and CCI using LAI2000 (more scatter) •Significant scatter in cotton LAI vs. CCI •Rough correlation between nitrogen treatments and LAI, CCI •Only one factor among many •Future work: •Analysis of AccuPAR LAI data •Consideration of water, other nutrients in analysis of nitrogen treatments

Acknowledgeme nts •NASA Student Airborne Research Program •NSERC •CSTARS, UC Davis •Shawn Kefauver •Dr. Susan Ustin •Paramount Farms

Questions ?