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Abstract

A near IR reflectance spectrophotometric calibration equation was developed for the rapid estimation of total N in ground samples of flue-cured tobacco leaves. Stepwise multiple linear regression techniques were used to develop various models. The most precise mathematical representation for estimating total N was a 7-term calibration equation (data from 7 wavelengths) based on the simple first derivative of the spectral data and it gave an r2 value of 0.91. A model based on the simple second derivative of the spectral data gave an r2 value of 0.88. Total N levels in samples from 1.54 to 3.05% were predicted with a standard error of 0.12%