Estimation of sugarcane leaf nitrogen concentration using in situ spectroscopy

The aim of this study was to explore the use of in situ spectroscopy for estimating sugarcane leaf nitrogen (IN) concentration Leaf spectral reflectance was Measured using a field spectroradiometer in the 3502500 rim range from sugarcane variety N 19 crops of 6-7 months Old Under on-farm conditions Lab determined leaf N concentrations of the samples taken ranged from 1 00% to 1 55% Vegetation indices based on simple ratio (SR), viz SIR (743, 13 16). SR (743, 1317) and SR (741, 1323) generated from first-order derivatives of leaf reflectance showed the best correlation with leaf N concentration, with r(2) values of 0 76 (P < 0 0 1), 0 75 (P < 0 01) and 0 74 (P < 0 01), respectively The root mean square errors of prediction (RMSEP) using a leave-one-out cross validation method were 0 089% (P < 0 01) for SR (743, 13 16). 0 092% (11 < 0 0 1) for SR (743, 3 17) and 0 084% (11 < 0 01) for SR (741, 1323) These results suggest that the HI Situ spectroscopy has potential use in predicting sugarcane leaf N (C) 2009 Elsevier B V All rights reserved