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constant although NDVI decreases. However, if we are only interested in the characterization of the development 
stage of the crop until reaching the climax, as many authors do, the two agronomical parameters seem to be 
good indicators since they show significant correlation with the NDVI. 
3.2. High spectral resolution analysis 
A similar analysis has been carried out for the correlations between the wavelength of the red edge, and the 
two mentioned agronomical parameters. Figures 4 and 5 show this spectral parameter versus LAI and biomass, 
respectively. 
Figure 4. Xre values versus LAI. Data corresponding to the development and period of maximum activity of the 
plants are represented by closed symbols (pre-L max data), whereas the others corresponding to the senescence of 
vegetation are shown in open symbols (post-L m ax data). The adjustment resulted curves have also been 
represented (continuous and dotted lines, respectively). 
680 
670 , , ; ; ; 
0 200 400 600 800 1000 1200 
BIOMASS (gm - 2 ) 
Figure 5. L re values versus biomass for the first period of the phenological cycle of the crop. The adjustment 
logarithmic curvet has also been represented.