SPAD Chlorophyll Meter in Greenhouse Horticulture
description
Transcript of SPAD Chlorophyll Meter in Greenhouse Horticulture
![Page 1: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/1.jpg)
SPAD Chlorophyll Meter in Greenhouse Horticulture
Stephen StanphillApril 12th, 2013
![Page 2: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/2.jpg)
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)
![Page 3: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/3.jpg)
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).
![Page 4: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/4.jpg)
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-ARS
![Page 5: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/5.jpg)
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
![Page 6: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/6.jpg)
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 levels
![Page 7: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/7.jpg)
• Non destructive to the plant
• Rapid data collection
• Can facilitate on-the-spot accurate N determinations
Functional Similarities
![Page 8: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/8.jpg)
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
Cost
![Page 9: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/9.jpg)
Horticultural Application• Cost of handheld Greenseeker unit is much lower than that of the
SPAD meter
• Faster speed of collection
• Ease of use
![Page 10: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/10.jpg)
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 NDVI
![Page 11: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/11.jpg)
Horticultural Application
With larger flower sizes and variations in color, the GreenSeeker unit becomes increasingly ineffective at determining N content
![Page 12: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/12.jpg)
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 plants
![Page 13: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/13.jpg)
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 plants
![Page 14: SPAD Chlorophyll Meter in Greenhouse Horticulture](https://reader036.fdocuments.in/reader036/viewer/2022062302/56816460550346895dd63aab/html5/thumbnails/14.jpg)
Conclusions
• In 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