Índices de vegetação para análise nutricional de Eucalyptus saligna Smith usando espectrorradiometria

Abstract

This study aimed to explain the association between macroand micro-nutrients with vegetation indices and to determine the most important wavelengths for each nutrient. In addition, equations capable of describing the nutritional status of Eucalyptus saligna Smith stands based on spectral radiometric data were suggested. The research was carried out in an 18-month-old plantation located in Barra do Ribeiro, Rio Grande do Sul State, Brazil. For the reflectance measurement 12 samples were used, which also served for the chemical quantification of macro and micronutrients. Nutrients were estimated by using multiple linear regression. The results showed that the visible and red-edge regions are more sensitive for discriminating nutrients in plants, mainly Mn, P, Ca, and S. In the macronutrient modeling, the estimation of N, Ca, and S, yielded the best adjustments, while in the micronutrient group the best adjustments were yielded by Zn, Cu, and Mn. Thus, the present study demonstrated the effectiveness of spectral radiometry to analyze nutrients in vegetation, which can be used in a fast and practical way to diagnose the nutritional status of eucalyptus.