Viticultura de precisão: avaliação da variabilidade espacial da produtividade e qualidade na casta Touriga Nacional no Alentejo

• Author(s): Pinto, Mariana Cavaca de Oliveira
• Date: 2015
• Persistent ID: http://hdl.handle.net/10400.5/9229
• Origin: Repositório da UTL
• Subject(s): precision viticulture; remote sensing; NDVI; segmented harvest
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Braga, Ricardo Pereira
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do Porto

In this dissertation it was intended to study the spatial variability in a vineyard with the variety “Touriga Nacional” in Estremoz, on the basis of the analysis of various parameters related to the vigour, yield and quality of grapes. After observation of the variability, we tested the use of vegetation index NDVI (Normalised Difference Vegetation Index), obtained by digital aerial photography on a flight performed at veraison, as a tool for the description of the spatial variability of the vineyard. On the basis of the results obtained in 54 vines, in this study, we analyzed the correlation between NDVI and the different variables. In the present essay, the NDVI shows high correlation with the variables related to the vigour and yield such as the Leaf Area Index to the Verasion (r=0,57) and Exposed Leaf Area to bunch closure (r=0,7), in relation to yield, it can be observed a correlation of 0,43. Compared to physical-chemical parameters of the grape, it was only found positive correlation with pH (r=0,56) and negative correlation with the Index of Total Polyphenols (r=0,51). The existence of a correlation between the NDVI and the variables above described, allows us to consider the possibility of using the NDVI to estimate the vigour and production of the vine. The segmentation of the vintage in low NDVI and high NDVI did not have significantly different values with respect to the physical-chemical analyses, however, in terms of sensory analyses, both wines coming from the segmentation of the vintage proved to be more balanced, resulting in an overall top evaluation