Estimativa do índice de área foliar por métodos óticos e sensoriamento remoto para calibrar modelo ecofisiológico em plantios de eucalipto em áreas de relevo ondulado

• Autor(a) principal: Paiva, Yhasmin Gabriel
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5282
• topic: Meteorologia agrícola; Análise foliar; Sensoriamento remoto; Eucalipto - Crescimento - Modelos matemáticos; Eucalipto - Efeito da radiação solar; Agricultural meteorology; Leaf analysis; Remote sensing; Eucalyptus - Growth - Mathematical models; Eucalyptus - Effect of solar radiation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

The purpose of this study was to estimate the leaf area index (LAI) in eucalyptus forest plantations, using optical instruments and satellite imagery to evaluate the response to the physical and climatic conditions of the study area, and based on these data, calibrate and simulate yields with an ecophysiological growth model. The study was conducted in four eucalyptus stands of two ages in the following two regions: Cocais, at a higher altitude and Rio Doce, at a lower altitude, in the Rio Doce basin, in eastern Minas Gerais. Nine plots were marked in each stand, according to the exposure of the relief surface. The experimental data were collected in August 2008 (dry season) and January 2009 (rainy season). The LAI was estimated by measures of the plant area index (PAI) by the equipment LAI-2000 (LI-COR) and hemispherical photographs. The expression PAI was adopted since these sensors do not measure only the leaf element. The method of destructive analysis was used to check the accuracy of the LAI estimates. Meteorological data were collected at two monitoring stations installed near the stands in each region of the study. The model 3PG (Physiological Principles in Predicting Growth) was run using the parameterization established in previous studies for the same regions. The 3PG was calibrated with vegetation indices (VIs) of the sensor Moderate Resolution Imaging Spectroradiometer (MODIS). The model simulation was performed based on the corrected global radiation according to the slope and exposure of the relief surface. It was found that the PAI derived from LAI2000 was the indirect method that correlated best with the observed LAI. Eucalyptus responded to climatic seasonality, with lower LAI values in the dry than in the rainy season. The LAI,in the stands at higher altitudes (Cocais) exceeded that of the lower plots (Rio Doce), probably due to the higher evapotranspiration demand in the Rio Doce basin. The incidence of solar radiation on the northern slope surfaces was higher, in agreement with the correction performed for inclined surfaces. On this face, again, higher LAI values were measured in the field and estimated by the model 3PG well as for other estimated variables that express the crop productivity. The results for the inclined areas were not conclusive. Studies should investigate whether the response pattern is repeated in analyses of the influence of the latitude of the site. The estimates of the model 3PG calibrated by the normalized difference vegetation index (NDVI) agreed well with the observed data and temporal data verified by MODIS-VI.