Intra-vineyard variability description through satellite-derived spectral indices as related to soil and vine water status

摘要

A time series of Landsat 8 OLI multispectral images acquired in the period May 2013 - February 2016 was used to investigate vineyard behaviour in terms of vigour and water content. The study site was located in the Castel del Monte DOCG area; a 'Moscato Reale' (syn. 'Moscato Bianco') vineyard was analysed. Normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) were calculated for all images (preventively calibrated and atmospherically corrected) to describe, at pixel level (30x30 m), vigour, plant and soil water status. Spectral indices cyclicity was also assessed to explore dynamics of vines growing season. Satellite-derived information was compared with ground parameters (midday stem water potential and soil water content), correlation tested and regression models for parameter estimation calibrated. Periodicity of vigour (NDVI) and water content (NDWI') along time was described using a Fast Fourier Transform approach, finding that the most vigorous part of vineyard corresponded to the most regular (cyclic) ones. Middle resolution multispectral imagery from satellite can be effectively used, at vineyard level, to describe cyclicity, water status and soil moisture. This is an important issue to focus on since,as Landsat OLI dataset is free, the entire process is economic enough to be consistent with cost and income of the farming system.