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IVES 9 IVES Conference Series 9 Analyse et modélisation des transferts thermiques dans un sol de vignoble. Effets des techniques culturales

Analyse et modélisation des transferts thermiques dans un sol de vignoble. Effets des techniques culturales

Abstract

Les facteurs naturels tels que le milieu dans lequel est cultivée la vigne jouent un rôle important sur la qualité du vin. Si on veut élaborer un bon vin, il est en effet essentiel de produire un raisin de qualité. Pour cela, il faut valoriser et optimiser l’effet terroir qui, pour l’instant, joue un rôle qui n’est pas très bien connu. Il est donc indispensable, par exemple, de disposer de relations scientifiquement établies et bien quantifiables pour faire admettre le système des aires d’origines contrôlées. R. Morlat (1989) et G. Seguin (1970) ont déjà réalisé des études sur le rôle de certains facteurs du sol sur la qualité du raisin. Ils ont notamment montré l’importance de la température du sol et du contenu en eau. Les relations entre la qualité et le terroir doivent cependant encore être clarifiées et surtout quantifiées afin d’être intégrées dans un système d’aide à la décision permettant d’optimiser les systèmes de conduite en fonction des facteurs naturels du site étudié.

Nous avons choisi, dans un premier temps, de nous intéresser principalement aux températures du sol. Ce facteur est en effet très important car il conditioime la croissance de la plante et certaines propriétés physiques du sol. La plupart de ces processus ne réagissent pas linéairement avec la température, il est donc indispensable de disposer de nombreuses données pour pouvoir évaluer les effets journaliers des températures du sol sur ces mécanismes. La mesure de la température du sol pose de gros problèmes car elle nécessite un dispositif qui est très lourd au niveau de l’installation, surtout dans les sols de vignoble, généralement hétérogènes. De plus, la mise en place des capteurs perturbe le milieu introduisant ainsi un biais dans les grandeurs qui seront mesurées.

C’est pour ces raisons que nous avons choisi de développer un modèle de transfert thermique applicable aux sols de vignobles. L’utilisation de lois physiques décrivant les échanges et des méthodes d’analyse et de modélisation micrométéorologiques paraissent aptes à apporter des réponses au problème posé par la recherche des facteurs jouant un rôle dans la qualité du raisin. Il en est de même pour l’explication des effets de différentes méthodes culturales (désherbage, travail du sol, enherbement).

Il est bien évident qu’il existe d’autres facteurs influant sur la qualité du raisin qui peuvent aussi caractériser l’effet “terroir”. Par exemple, la nutrition azotée et minérale de la plante joue aussi un rôle important, il est donc nécessaire d’étudier la disponibilité de ces éléments dans le sol, ainsi que leurs modes de transfert. De même, le climat de la région concemée est capital, il influe sur la plupart des grandeurs qui sont étudiées. Ces facteurs sont donc, dans un premier temps, étudiés séparément, l’objectif étant à terme la construction d’un modèle complet de l’élaboration de la qualité du raisin, où sont inclus tous les paramètres du climat, du terroir et du système de conduite.

Les transferts thermiques et hydriques sont étroitement liés, ils interagissent, on peut donc difficilement envisager des émdes séparées de ces deux phénomènes. On peut cependant considérer, du moins dans un premier temps, l’état hydrique comme une variable d’entrée.

Le but de l’étude entreprise est donc de comprendre et de quantifier les effets de différents types ouétats de sols et de différents mode de culture sur l’évolution de la température en profondeur. Pour cela, une bonne connaissance physique des transferts thermiques est nécessaire pour arriver à relier les caractéristiques thermodynamiques du sol à la propagation et au stockage de la chaleur.

DOI:

Publication date: March 25, 2022

Type: Poster

Issue: Terroir 1996

Authors

E. PRADEL, P. PIERI

Laboratoires de Bioclimatologie et d’Agronomie – Domaine de la Grande Ferrade – 33883 Villenave D’Ornon

Tags

IVES Conference Series | Terroir 1996

Citation

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