Análise da imagem digital para estimativa da área foliar em plantas de laranja 'Pêra'

摘要

This work had as purpose to evaluate two methods of the estimative of leaf area, in "Pêra" orange plants, by the digital image analysis obtained with scanner and digital camera. To determine the leaf area, one group of discs was placed on a reading scanner and the image obtained was stored. The same groups of discs were fixed over a white paper and photographed with a digital camera. The images obtained from the digital camera and the scanner was processed utilizing an image editor's tool that allows the pixels counting of a specific color, in this case green. To compare these two methods the discs were submitted to an optic integrator of green leaf, LICOR-3100 model, utilizing the same groups. It was collected 20 leaves (five in each square of the plant) for each parcel of one experiment to compare commercial fertilizers and Zn doses, applied by leaves spraying, in seven years old "Pêra" orange plants. The experiment comprehended seven treatments and four replications with a total of 28 parcels. The two methods presented high correlation with the estimated area considering the optic integrator of area the reference method. The analysis of the image obtained from the photographic camera, with 5.0 megapixel of resolution, had more precision when compared with the estimated area by the optic integrator.