Ξ March 1st, 2009 | → 0 Comments | ∇ A Day at a Time, Interviews, Technology, Wine News, Winemakers, Wineries |
After my exchange with Zed Rengel, a gifted soil scientist from the University of Western Australia, now comes a second look at vineyard soil by a superb winegrower from Oregon I loosely called ‘non-interventionist’: Jason Lett of The Eyrie Vineyards would perhaps be better understood as ‘pro-vine’. To that point, there are a number observations Jason makes below that I have never before heard expressed as clearly, invitations to new avenues of research. Indeed, Jason is no dreamer. He is a practical, humble man. He claims no knowledge the vineyard itself has not first expressed.
For additional detail I would encourage folks to read my May 13th, 2008 interview with Jason Lett.
Admin What is your definition of ‘health’ in vineyard soils?
Jason Lett The balanced vine. Soils that test “perfect” nutrionally may not support the vine properly, whereas others that test poorly may in fact offer perfect balance.
Is microbial species diversity an index of soil health?
JL I look at the macro level – the vines and the companion plants – because I’m no soil scientist. My understanding of the micro-processes are those observed from the macro level, for example the very slow progress of phylloxera in our vineyards, versus those of neighbors. I SURMISE that this has to do with a healthy soil ecosystem, but I have no proof! I leave that to the scientists.
Grape quality is to some degree dependent on a vine’s struggle for nutrition. How does the organic and/or conventional winegrower determine how much nutrition to add to a vineyard soil?
JL I am not a big believer in additions of any kind, even organic. I think the vine and its companion organisms are well able to provide for themselves, through mychorrhizal associations and natural mineralization. In fact, having had a few hundred million years to figure out their needs, I’d say that the vine and it’s companion organisms know best what they need and how to get it. Human approaches tend to be simplistic and blunt-force-type applications.
How is terroir affected, if at all, by organic additions to vineyard soil?
JL Any efforts to increase the homogeneity of any aspect of winegrowing will lead to homogeneous expression.
Could you expand a bit on your answer on the matter of soil quality and vine vigor and grape quality? I’m trying to get at the issue of the relation between a vine struggling in poorer or natural, unadulterated soils, what we might call terroir, and grape quality.
JL Yes. For starters: Terroir. A term so co-opted by marketeers and wine geeks trying to impress their dates that it should be ceremonially buried in a gathering of all true lovers of wine.
Terroir is a cultural term – the qualities which many people, over many generations, perceive from wines produced by many people from the same site over many generations. What are we missing here in the US? The GENERATIONS: of winegrowers, of vines, of wine drinkers. If terroir – the taste of place – is a true thing then it’s expression should transcend vine, clone, spacing, oak regime, farming practices, extractive technique, winemaker, vintage, and decade. Certain vineyards in the “old world” have shown they can transcend, after many hundreds of years of observation, all these illusory influences in favor of a deeper expression.
Yet every 20-something marketing director working for Domaine Le Generique wants to claim terroir for their brand.
I don’t claim terroir for my site. I have found there are immutable aspects to our vineyards that express themselves through the passing of my father’s winemaking generation to mine, but I am not arrogant enough to claim “terroir.” Culture is a better explanation: the techniques I inherited, the clones, the spacing, the environment of the cellar. Those will all have to be shaken up a few times before we will know if the site sings true.
My children’s great grandchildren may have the privilege, if we are lucky enough to be still making wine from our ground in a century or two, to claim terroir. Until then, it strikes me as sheer arrogance to do so.
So I can not speak to terroir. I can claim some knowledge of what makes wines that age well and that consistently express a certain spectrum of Pinot noir/Chardonnay/Pinot gris’ vast range – in short, good wines that cellar.
So, to do this, you need vines in which the canes are not too stout or too thin. You need vines which have just enough leaves but not too many. They should hang just the right amount of fruit, and they should do so without intervention or heavy thinning. A certain amount of struggle is vital, but not too much.
Notice that I am not applying any specific metric to any of these. That’s because what may work for one row may not for another. Or individual vine, for that matter.
I believe that you can achieve good balance in any soil that is basically suitable for viticulture by adjusting spacing and clone. If you have to manipulate with cover crop, irrigation, or fertilizer you haven’t done those basic jobs well. Beyond that, the vines must have a deeply resonant community of plants, animals, bugs, fungi, humans, and bacteria, and God knows what else living around them.
Then you pick the grapes, bring them to the cellar, and try not to screw them up. That’s the secret to winemaking, to growing grapes, everything that goes into the glass.
That’s my opinion, not terribly original or well put, but I do appreciate you handing me a soapbox to express it.
Very good answer. Now, knowing the importance of the first few centimeters of soil for microbial activity, what types of insecticides and herbicides currently in use play the greatest role in microbial population decline?
JL Shifts in the natural ground cover will result in a shift in microbial communities, whether herbicidal or not. Even mechanical tilling can result in big swings in the soil populations, away from fungal organisms and towards bacterial. Grapes tend to try to maximize fungal associations so this, in my understanding, is not a good practice to utilize in the vineyard. But back to herbicides: they too can shift the soil ecosystem. Roundup, for example, is a fairly “soft” chemical and is considered to be of low toxicity because it breaks down quickly. However, that breakdown is facilitated by bacteria, and the presence of large bacterial populations, plus the lack of host companion plants, can drive down the fungal populations important for grapes.
Do ‘native’ or ‘wild’ yeast populations vary from vineyard to vineyard? And does viticultural practice in general have an effect on ‘wild’ yeasts?
JL I believe wild yeasts do vary from vineyard to vineyard. As to viticultural practices, I don’t experiment widely with yeast in mind, so I can’t say. However, my father did some experiments with native yeasts in the early 1970’s and concluded that the yeasts of the time were problematic. These days I have been reintroducing native yeast fermentations very successfully, so I can only conclude that the increasing numbers of planted grape acreage in our region has shifted the native yeast populations for the better.
Is it possible to determine, based on a vineyard’s soil elemental profile alone, whether it is under an organic or conventional farming regime?
JL Elemental profile? You meant the chemical elements or the physical ones? Physically, it’s pretty easy to tell by eye, by species composition, by soil structure under the row.
How deep must a vine’s roots plunge before terroir may be detected?
JL About a half an inch.
How old must a vineyard be to best express terroir?
JL Vineyards express terroir surprisingly early. The 1975 Eyrie South Block Reserve made quite a stir around the world, from a vineyard in it’s ninth year after planting. The South Block still maintains the same strong sense of identity today.
Thank you, Jason.
JL Thanks for thinking of me!
Next up, later this week, my interview with Peter Schmidt, the final post of this modest series on vineyard soils.