Chlorophyll and nitrogen determination for plantation-grown Eucalyptus nitens and E-globulus using a non-destructive meter

Portable non-destructive meters are used successfully with many species for estimating foliar chlorophyll or nitrogen (N) content. In this study, we investigated the use of the Minolta SPAD-502 for estimating chlorophyll and N content of Eucalyptus nitens and E. globulus foliage. This meter measures leaf absorbance at wavelengths 650 and 940 nm to estimate chlorophyll or N. The accuracy of the SPAD was determined, and the effects of species, site and plant type (pot-grown versus field-grown) on the SPAD-chlorophyll or SPAD-N relationship were examined. There was a strong curvilinear relationship between foliar chlorophyll content and the SPAD chlorophyll index (CI). This relationship was species-specific, and could be applied to similar-aged E. globulus grown at two contrasting sites. It differed between pot- and field-grown plants, indicating that separate calibration curves may be required for glasshouse and field situations. It was concluded that the SPAD-502 is a useful tool for screening foliar chlorophyll content in E. globulus and E. nitens plantations if adequately calibrated. The SPAD proved less useful in estimating foliar N content; only a weak relationship existed between foliar N and Cl for E. globulus and E. nitens. (c) 2005 Elsevier B.V. All rights reserved.