The Science and Poetry of the Vine, An Interview With Alain Carbonneau

Ξ February 21st, 2014 | → 2 Comments | ∇ A Day at a Time, International Terroirs, Interviews, Languedoc/Roussillon, Wine & Politics, Wine History, Wine News |

Professor Alain Carbonneau is likely an unfamiliar name to much of the wine world. But like researchers and educators everywhere, he is among the most important figures in his field. A viticulturist with a specialty in canopy management, he pioneered the widely used Lyre vine training system. With over 400 publications to his credit, he has expanded not only the science of Viticulture but of Vine Physiology and Adaptation, Vineyard Climatology, Sustainability, and he has deepened our practical understanding of terroir. And though he may have recently retired from INRA and Montpellier SupAgro, he is busier than ever, as you will read. More, I know many will find his remarks on the pending move of the treasured vine holdings at Domaine de Vassal to Pech Rouge especially interesting.
 
My apologies for the length of the interview, but when introducing so important a figure in the science (and the poetry) of the vine, it is right and proper to give due deference, to let him have his say. And so we begin…
 
Ken Payton So how are you, Professor ?
 
Alain Carbonneau Very well. I am a busy retired man with a lot to do ! I am still in charge of GiESCO (Groupe International d’Experts en Systemes viticoles pour la CoOpération) and I am in charge of our historical review, Le Progrès Agricole et Viticole.
 
Looking over your CV, I noticed you felt strongly enough to mention your lasting interest in Literature and Philosophy, Culture and Poetry. Can you tell me a bit about this ?
 
AC I love to write. Sometimes I use the classical Alexandrine poetic form. When I was a student I liked that form very much. And last Saturday I presented two or three poems, one was a dedicated to encouraging students to go on in their studies and another was on a grape variety, Syrah.
 
So Viticulture was a way of summing it all up, the poetry, philosophy, science…
 
AC Yes. The vine was the entrance, the door to imagination.
 
That would seem so with the naming of the Lyre system of vine training you pioneered. And the importance of an aesthetics of vineyard architecture.
 
AC We realized vineyard architecture was very important; first to control the real micro-climate of the leaves and berries and also, indirectly, to assist root development. About 30 years ago we were surprised to find the vine responds to that. We now consider that the training system, or vine architecture in general, is part of the terroir. It is not an artificial element. It is actually something like a filter of different natural elements: Light, temperature, water, wind and so on. Even the wine can be determined by this architecture. Not just the soil and the climate, but the training system also makes a difference.
 
Traditionally the Goblet was dominant in this region…
 
AC Yes. Actually the Lyre system is a very open and high goblet. If you compare the Lyre to the traditional goblet of Chateauneuf du Pape, for instance, the Lyre is more linear, more uniform in its architecture, but the general shape is similar. And in my opinion it is the best for quality, at least for temperate climates.
 
What is Ecophysiology ?
 
AC The idea is to control the response of the vine with respect to growth regulation, fertility, and above all the maturation of the berry and the different components of maturation. All those elements, what I call Ecophysiology, respond to the vine architecture. [See chapter two of the linked article]
 
About rootstock selection, have you done research in that area ?
 
AC Yes. The key point for controlling the type and quality of the wine is to find the optimal water limitation. So you play on different keys: the rootstock, soil management, the variety to some extent, and the architecture. Those elements interact with the general climate and the general water balance. At the moment there is no scientific model explaining the art, but with experience we can find some good solutions. So, yes, I work a little bit on rootstocks, but principally in terms of water regulation.
 
About that, there is limited use of vineyard irrigation in France. Do you believe that climate change will require a rethinking of the regulations governing organic grape growing, for example ?
 
AC Yes. After all, water is a natural product ! Twenty years ago irrigation was taboo because the region was trying to increase quality recognition. Most of the growers were afraid that irrigation would destroy that image. And in fact, due to the certainty of climate change, because summers are increasingly dry – for at least 20 years here – the key to maintaining a regular yield is to control the water uptake. Of course we have to control water stress. If the stress is too much then we lose the proper expression of the vine. We can produce concentrated wines rich in alcohol or with some smoky taste or cooked fruit, but in general we are not looking for that. We prefer to produce wines with better balance, with some floral and fresh fruit character, mixed with spices.
 
And to achieve that we have to control water. So if the water stress is too much then we have to add water. This is the same for nitrogen deficiency. Everybody agrees that nitrogen deficiency does not enhance quality. Therefore irrigation is sometimes necessary. Then there is the question of competition for water. But that is a matter of vineyard and territory management. We encourage growers to capture water when it rains and to create networks of small dams and ponds. We can also use waste [gray] water from the winery and cellar. Wineries use a lot of water. So combining these sorts of water sources we can avoid competition with other users of water such as cities.
 
And by using the Lyre architecture we increase the exposed leaf area and the transpiration demand. Initially we thought the Lyre was not suitable here because it can increase the severity of the water deficit. In fact the opposite is true. In contrast to VSP and other canopies, the Lyre maintains better water comfort for the plant. There was less stress. How can this be, we wondered. It turns out the answer is that we have to deal with the vine in all seasons, not just during the driest week in winter. In spring the Lyre intercepts much more light, produces more sugar and encourages the roots to grow and strengthen, to grow deeper and explore a larger water reservoir in the soil. The root growth stops between fruit set and veraison, and that corresponds to the beginning of the driest period. Now, the Lyre may then exaggerate the demand in transpiration, but because of better root development, it is able to withstand this period of water stress.
 
Because you want to encourage roots to grow deep, do you mean to discourage drip irrigation, for example ?
 
AC No no no. This is a legend. That is only true if irrigation is the only source of water for the vine. Additional irrigation doesn’t modify the root morphology or the root distribution in the soil. To be sure there are a few more surface roots under the grapes, but not too much. And this also depends on the texture of the soil. If the drainage is good then right after irrigation the water sinks quickly to the roots. So in this case you can combine deep rooting with additional irrigation. We’ve studied this in our vineyard on campus. It has a very coarse sand with stones. We use only drip irrigation; perhaps 70% of the vines’ water requirements are satisfied this way. And the root systems are deep. So I agree that we have to avoid the surface watering of a vineyard where the root system is too close to the surface, but if we handle irrigation properly, this is not a problem.
 
There are at a minimum two schools of thought in the organic community: one holds that biodiversity – flowers, grasses, herbs – competes with the vine for water; then there is another persuasion which encourages inter-row biodiversity precisely because it denies water to surface roots and thus forces the roots down deeper to find water…
 
AC Yes. The ideal, I think, is to combine controlled irrigation and grass cover. Flowers are also encouraged.
 
How do ‘terroir sciences’ differ from ecophysiology ?
 
AC Ecophysiology is a pure discipline, a holistic science. The aim is to explain how the whole plant functions. You restrict water, you increase temperatures, for example, and then you check the plant’s response at all levels: the leaves, the fruit, the roots. The final objective is to build a model which can explain this functioning of the whole plant.
 
I regret that in France at least, that few young scientists are working in this field. Sadly, the priority is Molecular Biology, so everybody is going into that field. It is quite easy to publish, I understand that, but I believe it is time to give a better balance between these two scientific disciplines.
 
Even old school hybridization, despite its historical successes, is under-utilized…
 
AC Yes. And terroir science is a very integrated approach, something like sustainable viticulture. So the aim is to build a new vineyard combining new varieties, new techniques for soil management, new canopy management, and to find the optimal interaction among all of these elements. So it is a science of interactions. Ecophysiology is part of that.
 
There are all kinds of restrictions and requirements on grape varieties within the AOP system. In a world of climate change it would seem the system must adapt.
 
AC Yes. To be honest, I am afraid for the future of the AOP system because it is too rigid. I think the best solution could be to tolerate inside each AOP 1% of the surface area to be free for experimentation with new varieties, new rootstocks, new training systems, irrigation, and so on. And let the experimentation go on for 10 to 15 years after which we may learn valuable lessons and thereby encourage change. Due to climate change and due to social changes, it will be absolutely necessary to utilize other varieties in the mid-term. We therefore need changes within the AOP system.
 
What has always puzzled me is that farmers are the ones doing the practical labor, the experimenting, everyday. Yet even as they are learning, this new agricultural knowledge is not necessarily persuading the AOP to change.
 
AC I agree. The representation of growers in the official AOP is important. Many people elected to the AOP assemblies are among the most famous growers so they do not really want to change all that much. They are far too conservative. But in terms of regulation and law, it is possible for any AOP to change because the decisions are coming from the growers themselves. It is a question of democratic majorities. But I am a little bit afraid because even though we are certain of climate change, too few things are changing in the vineyard.
 
There is the enormous grape variety resource of Domaine de Vassal, for example. They are certainly ready and able to assist with any new initiatives and experiments.
 
AC Yes. There is a real problem here. Domaine de Vassal’s collection is huge. But if you want to determine the adaptation potential for different varieties, in fact that collection is not well-situated. It is a very good site to preserve genetic diversity, to note the growth cycles of a given variety or something like that. But to estimate adaptation to climate change, we have to change its location. I hope this collection can eventually be re-installed in a more suitable place.
 
So you are hoping for the relocation of Domaine de Vassal ?
 
AC Yes. Personally I think it is really necessary.
 
Even if grafting is required.
 
AC Yes, of course. Grafting is absolutely necessary if you want to determine the normal behavior of a variety. We have to separate the matter of varieties preserved in sandy soils from their real world application in other soil types. We need to experiment with their potential under normal conditions, which means grafting.
 
Where do you think would be a good location for the Vassal collection ?
 
ACI think INRA has an ideal site in Pech Rouge. There is plenty of space to install that collection. Especially if we want to select the very best varieties for tomorrow, and even if those varieties are very old. We may yet be surprised ! One example: I was in Lebanon a few years ago. I observed that Zinfandel was more susceptible to high temperatures than Marselan. It was really evident. We have those varieties at Vassal, but without proper real-world conditions no one could know that. So we must work with unknown or rare varieties with high oenological potential in the real world. And I am sure in the coming years we can select some old or rare varieties to diversify the range of wines available and to as well respond to climate change.
 
It is surprising that with the 1000s of varieties available in the world that we seem to see the same narrow range of choices in the marketplace.
 
AC Indeed, we have now found a new hybrid which is fully resistant to Downey and powdery mildew – no pesticide needed – but we still have to determine if the resistance is sustainable and stable over time. Now in terms of research, depending on soil type, we try to build a new viticulture using those varieties in no need of pesticides, combined with new architectures and soil management techniques including grass cover and drip irrigation.
 
So you believe science can ultimately overcome traditional barriers to innovation ?
 
AC Yes. I have worked in viticulture for 40 years and this is the first time, in France at least, that I have noticed a strong demand from growers to be able to plant new hybrids and to experiment.
 
What are the greatest risks with a move from Domaine de Vassal to a new location ?
 
AC Time and money. In our vineyard on the campus we have over 300 Vitis vinefera varieties. And they were transferred from Vassal. So we do have experience in the transfer of at least a part of the collection. Sometimes there are some mistakes. And sometime we fail. But it is a matter of time and means. And with a relocation, here is an great opportunity to check on the sanitary health of each plant. Indeed, at Vassal a full 50% of the plants are not fully ’safe’. I do hope INRA will provide enough funding to make this operation a success. It will take a minimum of 10 years, I believe. Ten hectares are waiting at Pech Rouge.
 
So relocation will require grafting. Does grafting change the character of finished wines ? Does it alter the vinifera variety in any way ?
 
AC Grafting on a resistant rootstock may change a vine’s general vigor, its fertility and and milieu; for sure you will change something in terms of maturity. But with respect to changing the flavor profile of the wine itself, I don’t think so. The problem is not that of the grafted vine; the problem is the non-grafted vine because it is not representative of a normal adaptation in a vineyard. Even if there is no phylloxera. Take Riesling, for example, which on its own rootstock is not fertile, it does not develop very well. But if you graft it on to a rootstock then it has good fertility and so on. So if you want to extrapolate the results from the collection to the practice, then you must be as close as possible to the practical conditions. For us the collection is not only the preservation of genes, it is also a tool for studying adaptation to a particular terroir.
 
Are you a little disappointed than you have now retired ? there seems to be so much going on !
 
AC Yes! This is the reason I am still working. In fact, we have begun experimental plantings in our vineyard in Pech Rouge to discover more about sustainable models for viticulture. These vines are only two years old, so I will be involved for some years.
 
Do you have your own personal vineyard ?
 
AC Yes, but it is very, very small. It is just for the weekends. I am very pleased to practice viticulture because it is important for a teacher to appreciate directly what are the problems in the field. Now, for example, I can say that due to climate change we can control the vineyard by using only four or five pesticide applications per year. Because I am doing just that !
 
Returning to Vassal for a moment, how long has this question of relocating been in the air ?
 
AC Thirty years. I was personally convinced 10 years ago that it was necessary to relocate, and for many reasons. But this operation is so huge that people prefer to ignore it. I think that the INRA in Paris was dreaming that some new in-vitro techniques would replace a field collection. But realistically, we are not preserving genes; we are preserving plants. It is not the same. Now everybody agrees on that. And I do hope that we can give to this exceptional collection the safe and secure environment it needs and deserves, and for a very long time. This is not the case at Vassal. Apart from problems with the owners, the land rental, competition with tourism, the main problem is one of salt water intrusion into the underground aquifer, which is an invisible effect of climate change. That is the basic problem with Vassal: salinity.
 
Nevertheless, there is a great deal of resistance to the move. A petition was recently circulated…
 
AC Personally, I think it is a mistake. But I understand my colleagues: they are afraid of losing this tool. This is the reaction. But in fact, this petition is counter-productive. This is my opinion. It is a question of sufficient technicians and money. It would have been better to have begun this 10 years ago. We had money then. But in the current economy, I hope we can do it. We must be optimistic! The positive effect of the petition is to give some consciousness to the hierarchy that this is really important to many, many people.
 
We began this conversation by touching on your poetry. Do you plan to publish ?
 
AC Well, after last Saturday’s poems I read to students and our new director, they were very pleased with them. So now I am quite obliged to publish! Perhaps I will write a poem on ampelography . It could be a good way to interest people to change varieties, to explore diversity… because, like poetry, wine is part of culture. Yes, it could be important for human health, but above all it is part of culture. I have some really good open-minded Muslim friends in Turkey. They are now producing very good wines. And I help them. I have just written an article on an old variety, Papazkarasi, and they are very enthusiastic about this grape. Wine culture can improve the relations between men. This is the most exciting part of our work.
 
Thank you, Professor Carbonneau.
 
AC You are welcome.
 
———————————————-
 
Ken Payton, Admin
 
Great thanks to Louise Hurren for her assistance.

 

2 Responses to ' The Science and Poetry of the Vine, An Interview With Alain Carbonneau '

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  1. Joel Burt said,

    on March 27th, 2014 at 4:57 pm

    Very nice interview, thanks!

  2. Admin, Ken Payton said,

    on May 18th, 2014 at 8:30 pm

    You are very welcome, Joel.

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