Understanding and managing wine production from different terroirs

A « terroir » is a cultivated ecosystem in which the vine interacts with the soil and the climate. Main climatic parameters include temperature, rainfall and reference evapotranspiration. Vine phenology and grape ripening is mainly driven by air temperature, but also by soil temperature. Soil provides water and minerals to the vine, in particular nitrogen. Over the past decades, tools have been developed to quantify terroir parameters. Small scale weather stations can yield temperature data at high resolution which can be used to provide refined maps of temperature summations. Models have been developed to predict phenology in relation to temperature. Vine water status can be assessed with a pressure chamber, or by means of carbon isotope discrimination measured on grape sugar (so-called δ13C). Vine nitrogen status can be assessed with the measurement of yeast available nitrogen (YAN). In this way, terroir parameters can not only be measured but also mapped. This approach allows precise vineyard management to optimize terroir expression, through plot selection, the choice of appropriate plant material in relation to soil and climate, vineyard floor management, fertilization and training system.