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IVES 9 IVES Conference Series 9 Climatic zoning of viticultural production periods over the year in the tropical zone: application of the methodology of the Géoviticulture MCC system

Climatic zoning of viticultural production periods over the year in the tropical zone: application of the methodology of the Géoviticulture MCC system

Abstract

L’objectif de cette recherche est le zonage climatique des périodes viticoles de l’année dans la Vallée du São Francisco, région brésilienne productrice de vins située en climat tropical semi-aride. Dans cette région, la production peut être échelonnée sur tous les mois de l’année. La région est placée sur climat viticole à variabilité intra-annuelle, qui correspond aux régions qui, sur des conditions climatiques naturelles, changent de classe de climat viticole en fonction de la période de l’année au cours de laquelle le raisin peut être produit. La méthodologie adoptée est celle du Système de Classification Climatique Multicritères Géoviticole (Système CCM Géoviticole) (Tonietto & Carbonneau, 2004), en utilisant les fonctionnalités de modulation des indices (indices homologues appliqués sur la phénologie locale des cépages). Les indices climatiques viticoles du Système (thermique, nycthermique et hydrique) ont été adaptés aux conditions biologiques du cépage Syrah de la région, qui présente un cycle moyen débourrement-récolte (d-r) de 4 mois. L’étude utilise une base de données climatiques journalières de la période 1976-2002, avec la simulation de 36 récoltes théoriques par an (une récolte théorique a chaque décade), soit un totale de 972 sur l’ensemble de la période étudiée. Ainsi, l’Indice Héliothermique (IH12d) à été calculé sur 4 mois tout au long de l’année. L’Indice de Fraîcheur des Nuits (IF3d) a été calculé sur les 3 décades précédentes la date théorique de récolte (période de maturation). La quantité de pluie en période de maturation (P3d) a également été prise en compte en fonction des effets sur l’incidence de pourriture. Les résultats ont permis de caractériser 3 périodes climatiques viticoles distincts dans l’année : Période “a” – conditions thermiques moins chaudes pendant le cycle d-r pour l’IH12d, conditions nycthermiques (IF3d) plus fraîches et très sec (P3d) en période de maturation ; Période “b” – climat intermédiaire entre la période “a” et “c” pour l’IF3d et l’IH12d et sec à très sec pour P3d (la période “b” peut être subdivisée en 2 sous-périodes : l’une que s’initie en sortant de la période chaude et humide “c”, avec une réserve hydrique utile au niveau du sol, et évolue avec la chute des températures ; et l’autre sous-période qui débute avec l’augmentation des températures et que finie juste avant la rentrée de la période humide “c”) ; Période “c” – Le plus chaud pour l’IF3d et l’IH12d et sub-humide pour P3d. Les résultats montrent que la production de raisin de cuve pour un même cépage présente des caractéristiques potentielles distinctes en fonction des périodes de production “a”, “b” et “c”. D’une façon générale, la période “c” est la plus susceptible a une maturité du raisin incomplète en fonction du risque de pourriture (pluie et température élevée), qui peuvent amener à une récolte avant la complète maturation du raisin. Déjà les périodes “a” et “b” sont les plus aptes a une bonne maturation du raisin. La période “a” est celle qui présente le moindre risque de pluie et des températures les plus fraîches, avec la possibilité du contrôle total de la disponibilité hydrique du sol par l’irrigation. La probabilité d’occurrence des indices climatiques à été caractérisé par décade et par quartile comme information d’aide à la décision (risque ou avantages) des périodes de production. Des études complémentaires, notamment l’estimation de la réserve hydrique potentielle (Indice de Sécheresse – IS) du sol seront développées. On peut conclure que le concept de climat viticole à variabilité intra-annuelle du Système CCM Géoviticole peut être utilisé comme élément de zonage pour l’établissement, dans un même vignoble, des périodes de l’année avec un potentiel climatique supérieur de production de raisin de cuve. Ce critère climatique va être utilisé dans le zonage intégré de la région, notamment avec les facteurs édaphiques.

The objective of this research is the viticultural climatic zoning of the production periods over the year in the São Francisco Valley, a Brazilian grape-growing region located in semi-arid tropical climate. In this region, the production can be spread over all months of the year. The region is situated in climate with intra-annual variability, that corresponds to the regions which, under natural climatic conditions, change the class of viticultural climate according to the period of the year during which the grape is produced. The methodology adopted is that of the Géoviticulture Multicriteria Climatic Classification System (Géoviticulture MCC System) (Tonietto & Carbonneau, 2004), employing the modulation functions of the indices. The viticultural climatic indices of the System have been adapted to the biological conditions of the Syrah variety, which has an average cycle of 4 months from bud burst to harvest (d-r) in the region. The study is based on a daily climate database from 1976 through 2002, simulating 36 theoretic harvests per year (one theoretic harvest at every ten 10 days), amounting to a total of 972 harvests in the whole period covered by the study. In this way, the Heliothermal Index (HI12d) was calculated over 4 months throughout the year. The Cool Night Index (IF3d) was calculated over the 30 days that preceded the theoretic harvest (maturation period). The amount of rain (P3d) in the maturation period was equally been taken into account according to the potential effect of the incidence of bunch rotting. The results have allowed to distinguish 3 climatic viticultural periods during the year: Period “a” – less warm during d-r cycle (IH12d) and for night temperatures (IF3d) and very dry (P3d); Period “b” – intermediate climate between “a” and “c” period for IF3d and IH12d and dry to very dry for P3d (the period “b” can be subdivided into 2 sub-periods: one which starts with the end of the warm and sub-humid period “c”, with a useful water reserve of the soil, and evolves with the fall of the temperatures, and another which starts with the increase of the temperatures and finishes before the sub-humid period “c” returns); Period “c” – the warmest for the IH12d and IF3d, and sub-humid for P3d. The obtained results allow defining the periods “a” and “b”, even with different climatic viticultural potential, as being the most favorable for the production of grapes for wine. The probability of occurrence of the values of the climatic indices (climatic risk or advantages) was characterized at a ten-day level throughout the year. Other index to complement the study will be included, especially the potential water balance of the soil (dryness index – IS). It can be concluded that the concept of the viticultural climate with intra-annual variability of the Géovitivulture MCC System can be used as a zoning element for establishing, in the same vineyard, periods of the year with a higher climatic potential for the production of quality grapes for wine. This climatic criterion will be used in the integrated zoning of the region, especially with the edaphic factors.

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Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

J. Tonietto (1) and A.H. de C. Teixeira (2)

(1) Embrapa – Centre National de Recherche de la Vigne et du Vin – Cnpuv, Rua Livramento, 515 ; 95700-000 – Bento Gonçalves, Brésil
(2) Embrapa – Centre de Recherche du Tropique Semi-Aride – Cpatsa

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Keywords

Tropical, intertropical, vin, raisin, qualité, climat avec variabilité intra-annuelle, zonage climatique, Système CCM Géoviticole 

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IVES Conference Series | Terroir 2004

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