Spatial analysis of within-vineyard grape vine sensitivity to solar irradiance patterns. A case study using pinot noir in a complex terrain

14225International audienceWe analyze how the patterns of the solar irradiance affect the growth of Pinot noir grapevines at stand-scale over a hilly terrain bounded by a coniferous forest. The study area is located on the “Vineyard Cost” that produce some of the best wines of the Burgundy region. The work is based on i) a Geographical Information Systems (GIS) and ii) the joint use of both irradiance and phenological models. Results show that the patterns of irradiance deficit are the primary driving force of the growth. Linear trends display good correlation between the total deficit of irradiance, and the developped growth index (R2 up to 0.96). Trends appear strongly modulated by position of the grapevines within the stand. A quadratic relationship between growth index and temperature anomalies (R2 = 0.92) is observed for the low-lying part of the stand. This result suggests the impact of low minimum temperature due to cold air drainage and stagnation. Results lead to propose a model able to capture at stand-scale 90% of the whole spatial variability of the growth. The model accounts for the diffuse component of the deficit of irradiance and the squared temperature anomalies. Combining such models through the use of GIS enables to better understand the driving mechanisms of grapevine growth over complex terrain, towards a better management of the “terroir” potential