in Greenhouse Horticulture Stephen Stanphill April 12 th 2013 Introduction SPAD SoilPlant Analysis Development Released in 1984 Minolta Co Ltd Japan A lightweight handheld meter for measuring the chlorophyll content of leaves without causing damage to plants Konica Minolt ID: 185351
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Slide1
SPAD Chlorophyll Meter in Greenhouse Horticulture
Stephen Stanphill
April 12
th
, 2013Slide2
Introduction
SPAD: (Soil-Plant
Analysis
Development)Released in 1984 (Minolta Co. Ltd, Japan)A lightweight handheld meter for measuring the chlorophyll content of leaves without causing damage to plants. (Konica Minolta) Slide3
Introduction
The SPAD meter determines the relative amount of
chlorophyll
present by measuring the absorbance of the leaf in two wavelength regions (650 and 940). Slide4
Background
Increasing
SPAD
values indicate higher concentrations of Chlorophyll per leaf unit area.Each crop has a unique SPAD range
University of Missouri and USDA-ARSSlide5
Y.Y. Cho, et. al. Scientia
Horticulturae
, 2007
SPAD values also show linear correlation to other plant variables.Leaf dry weight plotted against SPAD readings in hydroponically grown cucumbers (
Cucumis sativus L.)SPAD data was also utilized to predict leaf area in this experiment
Determining SPAD Significance Slide6
Determining SPAD Significance
Compare SPAD values to N – rich “strips” in greenhouse
Use predetermined industry or university standards as a reference
Collect samples for foliar analysis after SPAD testing to develop an algorithm for predicting chlorophyll content or Nitrogen levelsSlide7
Non destructive to the plantRapid data collectionCan facilitate on-the-spot accurate N determinations
Functional
SimilaritiesSlide8
Unit
Cost
SPAD 502 Plus Chlorophyll Meter
$2,195.00
SPAD 502DL Plus Chlorophyll Meter with Data Logger & RS-232$2,595.00
Greenseeker
® Handheld Crop Sensor
$495.00
CostSlide9
Horticultural Application
Cost of handheld
Greenseeker
unit is much lower than that of the SPAD meterFaster speed of collection
Ease of useSlide10
Horticultural Application
Flowering plants begin to interfere with
GreenSeeker
data collection at anthesis SPAD readings are not affected by background reflectance
Retail floriculture and other horticultural uses could be problematic for NDVI collection
Infrared Image Showing NDVISlide11
Horticultural Application
With larger flower sizes and variations in color, the
GreenSeeker
unit becomes increasingly ineffective at determining N content Slide12
Limitations
SPAD readings cannot be taken from very young seedlings
GreenSeeker would be much more effective at determining N values for flats of many small plantsSlide13
Solutions
SPAD Chlorophyll Meter
Determine cost effectiveness of spending 4 to 5 times more on a tool that will not require the extra labor and inventory loss incurred by the alternative
Handheld
GreenSeeker
Segregate test plants for disbudding and NDVI data collection
Forego data collection of mature plantsSlide14
ConclusionsIn many ways the SPAD meter is inferior to the more efficient hand-held
Greenseeker
unit for greenhouse horticulture work
In many horticultural uses however, there may always be a need for the more expensive SPAD unit