Desenvolvimento fenologico do trigo (cultivar IAC 24 - Tucurui), comportamento espectral e utilização de imagens NOAA-AVHRR

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The agronomic development of wheat (Triticum aestivum L.) cultivar IAC-24 - Tucuruí and the seasonal evolution of its spectral characteristics were evaluated under field conditions. The study was carried out at an irrigated commercial farm, located in the municipality of Paranapanema, SP. Field experimental observations were collected during the 1995 growing station, from May to August, in seven data of campaign. Biophysical parameters included canopy height, density of plant, number of leaves, phytomass (fresh and dry weight of aerial part of plant and of leaves), leaf area, and leaf area index (LAI). The spectral data included the field radiometry and the NOAA-AVHRR satellite images. Reflectance factor spectra of seven data were measured and then the mean values of the reflectance factor between 580 and 680nm (channel 1) and from 725 to 1,100nm (channel 2) of NOAA, and RATIO, NDVI, and TVI vegetation indexes were calculated. The NOAA-AVHRR images were sectored and radiometric calibration and atmospheric correction were made. Spectral variables from field radiometry were correlated to biophysical variables in each growth stage. Afterward field spectral variables were compared to orbital spectral variables. Maximum reflectance in the near infrared band was reached at beginning of heading process, when maximum LAI was also observed. The vegetation indexes of RATIO, NDVI and TVI had similar behaviours with the maximum values occurred at beginning of heading stage such as it was for maximum LAI. The relationships between biophysical and spectral variables were dependent of growth stage of the crop. The best correlations were obtained from heading through middle maturity. The lower difference between spectral and field data was obtained for TVI, with difference of 4.5%, average of four data values, followed by NDVI. Higher difference was observed to RATIO vegetation index.

ASSUNTO(S)

analise espectral trigo espectro solar sensoriamento remoto satelites meteorologicos

ACESSO AO ARTIGO

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