Terroir 2004 banner
IVES 9 IVES Conference Series 9 Study and valorization of vineyards “terroirs” of A.O.C. Cahors (Lot, France)

Study and valorization of vineyards “terroirs” of A.O.C. Cahors (Lot, France)

Abstract

In the current context of market competition and consumption evolution, it is necessary to produce wines of a genuine typicity. The Terroir represents an unique and irreproducible inheritance that can be valorized through the origin and the sensory characteristics of the wines.
Since 1989, the Expérimental Association of « la Ferme Départementale d’Anglars-Juillac » has led research and experimentation on vineyard terroirs, aimed at direct valorization for the winegrowers. The objective is to know (1) the wine-producing potentials of each terroir of the Cahors Appellation, for the principal vine grape cultivars of the Appellation: Malbec N or Cot N or Auxerrois N, (2) the vine behaviour on these terroirs and (3) to valorize this knowledge through technology, agronomy and enological procedures adapted to each terroir.
Cartography of the whole A.O.C. Cahors has been realized (22000ha). Nine terroirs have been identified according to the type of soil and the landscape situation: alluvial terraces of the Lot, “grèzes”, calcareous hillsides, high calcareous plateaus (eventually with marl), and red clays from sidérolithique formations. Agronomic and enological studies of a representative parcel of each terroir have been done since 1994. Pedological pits have also been done with physical and chemical analyses of each described horizon. Each year, maturity controls are carried out on these parcels; each is separately vinified with the same protocol. Wines are analyzed and tasted.
Results show that qualitative terroirs exist on alluvial terraces of the Lot, as well as on high calcareous plateaus. It is not the chemical nature (acid or calcareous) of the soil but the thickness of the soil which determines the quality of a terroir, in relation with the regularity of vine hydrous nutrition. For all that, some terroirs seem well adapted to produce vintage wines, whereas other terroirs seem more adapted to produce regional wines or wines for blending.
This study provides an agronomic and enological basis for advising wine-growers, in order to lead each terroir to its qualitative optimum: adaptation of the cultural practices, especially for new plantations (choice of the rootstock, soil management); adaptation of the method of vinification according to the terroir. The wine-grower has to take care of the terroir, the quality of the grape harvested and the wine. This study has led to a qualitative improvement of A.O.C. Cahors wines. The Cahors Appellation is now experiencing an infatuation for the most qualitative terroirs.
In the future, the start-up of the hierarchical system of the A.O.C. Cahors terroirs and the creation of vintage wines, will allow a large communication on wine quality and typicity, favorable to the whole Appellation Cahors wine business.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

Francis Laffargue (1), Elisabeth Besnard (1) and Marc Garcia (2)

1) Association d’Expérimentation, Ferme Départementale, 46140 Anglars-Juillac, France
2) ENSAT, Centre de Viticulture-Œnologie de Midi-Pyrénées, Avenue de l’Agrobiopole, Auzeville-Tolosane, BP 107 F, 31320 Castanet-Tolosane Cedex, France

Contact the author

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

Modeling island and coastal vineyards potential in the context of climate change

Climate change impacts regional and local climates, which in turn affects the world’s wine regions. In the short term, these modifications rises issues about maintaining quality and style of wine, and in a longer term about the suitability of grape varieties and the sustainability of traditional wine regions. Thus, adaptation to climate change represents a major challenge for viticulture. In this context, island and coastal vineyards could become coveted areas due to their specific climatic conditions. In regions subject to warming, the proximity of the sea can moderate extremes temperatures, which could be an advantage for wine. However, coastal and island areas are particular prized spaces and subject to multiple pressures that make the establishment or extension of viticulture complex.
In this perspective, it seems relevant to assess the potentialities of coastal and island areas for viticulture. This contribution will present a spatial optimization model that tends to characterize most suitable agroclimatic patterns in historical or emerging vineyards according to different scenarios. Thanks to an in-depth bibliography a global inventory of coastal and insular vineyards on a worldwide scale has been realized. Relevant criteria have been identified to describe the specificities of these vineyards. They are used as input data in the optimization process, which will optimize some objectives and spatial aspects. According to a predefined scenario, the objectives are set in three main categories associated with climatic characteristics, vineyards characteristics and management strategies. At the end of this optimization process, a series of maps presents the different spatial configurations that maximize the scenario objectives.

A multidisciplinary approach to evaluate the effects of the training system on the performance of “Aglianico del Vulture” vineyards

Vineyards are complex agro-ecosystems with high spatial and temporal variability. An efficient training system may counteract the adverse effects of this variability. Moreover, considering the climate change issues, choosing an efficient training system that enhances water use and protects the vines from radiative thermal stress has become a priority for the farmers. A multidisciplinary approach that assesses the soil-crop-yield-wine relationships of vineyards in a distributed and holistic way could bring added knowledge on the behavior of the different training systems. This ongoing research aimed to implement a multidisciplinary approach to study the behavior of “Aglianico del Vulture” grapevines trained with two different systems: a spurred cordon (SC) and an “Alberello in parete” (AL), grown in a high-quality wine production area of Basilicata region (Italy). The approach merged several methods and scales of soil, ecophysiology, must/wine quality, and spectral data collection to assess the influence of the training system. Homogeneous zones (HZs) in both training systems were defined through a procedure based on geomorphological classification, unmanned aerial vehicles (UAV) images analysis, and a traditional soil survey supported by geophysical scanning. During the 2021 season, TDR probes monitored soil water content, while grapevine health status was assessed using eco-physiological measurements (LWP, chlorophyll content, PSII photosynthetic efficiency, LAI, and point-based field spectroscopy). These grapevine in-vivo measurements validated the spectral vegetation indexes (NDVI, RENDVI, CVI, and TVI) derived from the UAV multispectral imagery, which monitored the grapevine status in a distributed and non-invasive way. Grape yield, quality of berries, must and wine were measured to assess the effects of the training systems. The first experimental year results showed the variability of the vineyards and revealed relationships among soil parameters, crop characteristics, and vegetation indices of the SC and AL training systems. This multidisciplinary study could bring new insights into the vineyard training system’s effects on grape yield and wine quality.

Mesoclimate impact on Tannat in the Atlantic terroir of Uruguay

The study of climate is relevant as an element conditioning the typicity of a product, its quality and sustainability over the years. The grapevine development and growth and the final grape and wine composition are closely related to temperature, while climate components vary at mesoscale according to topography and/or proximity to large bodies of water. The objective of this work is to assess the mesoclimate of the Atlantic region of Uruguay and to determine the effect of topography and the ocean on temperature and consequently on Tannat grapevine behavior.

A better understanding of the climate effect on anthocyanin accumulation in grapes using a machine learning approach

The current climate changes are directly threatening the balance of the vineyard at harvest time. The maturation period of the grapes is shifted to the middle of the summer, at a time when radiation and air temperature are at their maximum. In this context, the implementation of corrective practices becomes problematic. Unfortunately, our knowledge of the climate effect on the quality of different grape varieties remains very incomplete to guide these choices. During the Innovine project, original experiments were carried out on Syrah to study the combined effects of normal or high air temperature and varying degrees of exposure of the berries to the sun. Berries subjected to these different conditions were sampled and analyzed throughout the maturation period. Several quality characteristics were determined, including anthocyanin content. The objective of the experiments was to investigate which climatic determinants were most important for anthocyanin accumulation in the berries. Temperature and irradiance data, observed over time with a very thin discretization step, are called functional data in statistics. We developed the procedure SpiceFP (Sparse and Structured Procedure to Identify Combined Effects of Functional Predictors) to explain the variations of a scalar response variable (a grape berry quality variable for example) by two or three functional predictors (as temperature and irradiance) in a context of joint influence of these predictors. Particular attention was paid to the interpretability of the results. Analysis of the data using SpiceFP identified a negative impact of morning combinations of low irradiance (lower than about 100 μmol m−2 s−1 or 45 μmol m−2 s−1 depending on the advanced-delayed state of the berries) and high temperature (higher than 25oC). A slight difference associated with overnight temperature occurred between these effects identified in the morning.