Resumo

CRUZ-DURAN, Jairo Aarón de la; SANCHEZ-GARCIA, Prometeo; GALVIS-SPINOLA, Arturo  e  CARRILLO-SALAZAR, José Alfredo. Spectral Indexes in Sweet Pepper for Diagnosis of Nitrogen Nutrient Status. Terra Latinoam [online]. 2011, vol.29, n.3, pp.259-265. ISSN 2395-8030.

The spectrum of the light reflectance for the plant’s foliage is a precise indicator of the fraction of the vegetable coverage, which is highly associated with the radiation interception and crop nutrimental condition. The objective of this research consisted in relating the spectral signatures in pepper to the nitrogen concentration in leaves. A pepper crop experiment was established in hydroponics conditions and a gradient of concentration of nitrate was generated in the nutrient solution: 0, 4, 8, 12, 16, and 20 meq L-1. During the pepper growth cycle, the reflectance in the pepper was monitored in three bands of the visible spectrum and in two of the near infrared, digital images were taken to determinate the foliar area index (FAI) and vegetable samples were collected for the analysis of nitrogen concentration. The utilization of the indexes of vegetation, as the green model (830 nm / 560 nm) - 1 and normalized rate (NDVI 560) / (NDVI 660), in the interpretation of the spectral signatures obtained by the spectrometer, allowed to establish critical levels of reflectance. The indexes of vegetation showed a high correlation (r2 > 0.8) with nitrogen deficiency minor of 3%.

Palavras-chave : remote sensors; NDVI; spectral index.

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