Complementarity of measurements of electric resistivity of soils and ΔC13 of must in studies and valorization of wine terroirs

The correlations between vine water deficit cumulated over the ripening period of grapes, assessed by ΔC13 in must sugar, and the main analytic variables of grapes are significant. As a result ΔC13 is a useful tool in zoning homogeneous areas according to their technological qualities when harvesting. There is no significant correlation between ΔC13 in must sugar and soil electric resistivity in the same zone. Thus it is impossible to combine a few measurements of ΔC13 and a zoning of electric resistivity to distinguish areas of which the aptitudes are different. In the event of little water deficit (ΔC13<-25,5‰), a pedological study based on zoning by means of electric resistivity is a complementary tool of zoning according to water uptake conditions, since harvest quality varies a lot with the texture of the sub-soil and its geophysic behaviour.