ASA Southern Branch 2007 Annual Meeting
February 4-6, 2007
Mobile, AL
ASA Southern Branch 2007 Annual Meeting
February 4-6, 2007
Mobile, AL
Conventional methods for the measurement of leaf chlorophyll in tree crops, including date palm, are laborious and slow, and always destructive to leaf tissue. Generally, these methods involve taking leaf samples from the field to the laboratory where they are subjected to extraction with acetone or similar organic solvents. An alternative method is the use of a portable Chlorophyll Meter (SPAD-502) developed by the Soil Plant Analysis Development (SPAD) unit of Minolta Camera Company, Japan to measure total chlorophyll in the field. The meter is lightweight (approximately 250g), is powered by two AA alkaline batteries, has a 2-second interval between measurements, and can store up to 30 measurements. The principle of measurement of SPAD-502 is based on the difference in light attenuation at 650 and 940 nm. Operationally, measurement of leaf colour is accomplished by inserting a leaf blade into the head of the SPAD-502 Chlorophyll Meter.
In studies conducted at Sultan Qaboos University in 2004 and 2005 on date palm, Phoenix dactylifera cv Khalas, SPAD readings were significantly correlated with acetone extracted chlorophyll of date palm leaves. The correlation coefficients (R2) ranged from 0.86** to 0.93**. SPAD readings and nitrogen contents were also highly correlated, the correlation coefficients (R2) being 0.82** to 0.91**. Similar high correlation (R2 = 0.85**) was obtained for average bunch yield/ tree and SPAD chlorophyll readings. Although our results have clearly shown that the SPAD-502 Chlorophyll Meter can be used to measure chlorophyll content in date palm leaves, we require further experimentation to determine its usefulness in predicting N use in date palm as has been demonstrated for corn and wheat.
See more of Crops--Specialty Crops
See more of The 2007 SAAS Convention