Caracterización espectral de la quinua (Chenopodium quinoa) de la provincia de Chimborazo mediante la técnica de espectro-radiometría de campo

Abstract

The aim of the experimental work was to spectrally characterise the quinoa (Chenopodium quinoa) grown in the province of Chimborazo. The field spectrometry technique was applied, and the FiledSpec4 Spectrometer was used. The spectra of four leaves and the flower were collected from three randomly selected plants at two phenological stages (beginning of flowering and physiological maturity) of the different types of quinoa, in the canton of Colta (beginning of flowering and physiological maturity stage) and in INIAP (beginning of flowering stage). The spectral similarity value (SSV) and the spectral angle mapper (SAM) were used to describe the difference between the spectra obtained. Using Ward's method, a global hierarchical clustering was performed to establish clusters of leaf and flower spectra sharing similar characteristics. The health status was studied by calculating the normalised difference vegetation index (NDVI) and the green normalised difference vegetation index (GNDVI), among others. The spectral signature in leaves A (FEHA) obtained were: NDVI= 0.8754, GNDVI= 0.69755, NDMI= 0.42886, GCI= 4.7948, SIPI= 0.9958 and the spectral signature in flowers A (FEFA) were: NDVI= 0.6363, GNDVI= 0.6874, NDMI= 0.4487, GCI= 4.4628, SIPI= 1.1395. Based on these results, it is shown that reflectance spectra are subject to parameters such as the amount of water and chlorophyll, thus finding spectral signatures of high similarity in shape and magnitude in plants belonging to the same phenological stage. From the experiences obtained, it is recommended that the sampling be carried out in time periods that are not so distant from each other, as the constant development of the plant can lead to changes in the shape and magnitude of the spectral signature.