Presentation on theme: "SPAD Chlorophyll Meter in Greenhouse Horticulture"— Presentation transcript:
1 SPAD Chlorophyll Meter in Greenhouse Horticulture Stephen StanphillApril 12th, 2013
2 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)
3 IntroductionThe SPAD meter determines the relative amount of chlorophyll present by measuring the absorbance of the leaf in two wavelength regions (650 and 940).
4 BackgroundIncreasing SPAD values indicate higher concentrations of Chlorophyll per leaf unit area.Each crop has a unique SPAD rangeUniversity of Missouri and USDA-ARS
5 Determining SPAD Significance 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 experimentY.Y. Cho, et. al. Scientia Horticulturae, 2007
6 Determining SPAD Significance Compare SPAD values to N – rich “strips” in greenhouseUse predetermined industry or university standards as a referenceCollect samples for foliar analysis after SPAD testing to develop an algorithm for predicting chlorophyll content or Nitrogen levels
7 Functional Similarities Non destructive to the plantRapid data collectionCan facilitate on-the-spot accurate N determinations
8 Cost Unit Cost SPAD 502 Plus Chlorophyll Meter $2,195.00 SPAD 502DL Plus Chlorophyll Meter with Data Logger & RS-232$2,595.00Greenseeker® Handheld Crop Sensor$495.00
9 Horticultural Application Cost of handheld Greenseeker unit is much lower than that of the SPAD meterFaster speed of collectionEase of use
10 Horticultural Application Flowering plants begin to interfere with GreenSeeker data collection at anthesisSPAD readings are not affected by background reflectanceRetail floriculture and other horticultural uses could be problematic for NDVI collectionInfrared Image Showing NDVI
11 Horticultural Application With larger flower sizes and variations in color, the GreenSeeker unit becomes increasingly ineffective at determining N content
12 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
13 Solutions Handheld GreenSeeker SPAD Chlorophyll Meter Segregate test plants for disbudding and NDVI data collectionForego data collection of mature plantsDetermine 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
14 ConclusionsIn many ways the SPAD meter is inferior to the more efficient hand-held Greenseeker unit for greenhouse horticulture workIn many horticultural uses however, there may always be a need for the more expensive SPAD unit
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