Adam Lee wrote: ↑April 5th, 2021, 4:00 am
Marcus Goodfellow wrote: ↑April 4th, 2021, 9:01 pm
Alan Rath wrote: ↑April 4th, 2021, 8:46 pm
Aside from me pulling your chain a bit, there’s an interesting discussion to be had here: you have a French grower saying that irrigation is bad, and the resulting wine is inferior to non-irrigated. I initially interpreted that to mean vineyards which get natural irrigation (random rain) are superior. But your argument seems to be (if I’m interpreting correctly) that dry farming may be the best of all, although a little rain here and there won’t hurt anything.
One thing I’m curious about: if deep roots are good, but irrigation causes vines to be “lazy” and feed from more shallow roots, how does rain promote deep roots?
Frankly, I’m not entirely convinced that deep roots are all that important; and I’m not sure how you prove something like that. But now we’re into the “conventional wisdom” part of our program...
So your first paragraph interpets my opinion correctly.
But the follow up is that rain does not promote deep roots, drought does. The vintages without rain that sends plants into water deficit will help force the plant to seek the water table down below topsoil. Which is why the person preferring deep roots will wade through the dry vintages and rhe vines suffering a bit. (My comments are not applicable to areas as arid as say Red Mountain).
And for whether deeper roots make a difference: the Willamette Valley median for depleting top soil moisture during our dry(ish) summers is 35”. In the Dundee Hills the soils are 48-72” deep and clay based basalt. They hold moisture very, very well and I would hypothesize that the vines there very, very rarely run out of water. In the Ribbon Ridge AVA, the sedimentary soils don’t hold moisture well at all and are generally 12-24” deep. These are vines in water deficit every summer until the roots hit the water table, and you can tell when they do.
We make wines from both AVAs, as well as the Eola-Amity Hills where soils vary considerably but the more common Nekia series is about 36” deep(mixed needs for water based upon the specific vintage weather).
There’s definitely a difference between the wines(terroir) that I ascribe to the differences in water stress. But which is better is definitely personal taste.
Thanks for your comments on this. I appreciate them. Having made wine from these areas myself, why do you necessarily ascribe these differences to water stress rather than to other differences - such as the effects of the Van Duzer Corridor in Eola-Amity? Have you ever done pressure bombs in say the Dundee Hills to see vine moisture content compared to Ribbon Ridge? It's somewhat time consuming but not all that difficult to do.
I shouldn’t have implied that I ascribe all of the differences in the wines to whether the vines are in water deficit or not. There are a myriad of factors making differences in the wines, including the prevailing breezes.
But the differences in soil waterholding capacity are a big player.
I have not done pressure bombs. But I do walk in the vineyards very, very regularly through the years.
You can feel the differences, including the Van Duzer effect which is much higher at Temperance Hill. At Whistling Ridge the wind comes down from the north, not up from the Van Duzer corridor. Both Fir Crest, tucked into the rain shadow of the coast range and Durant in the Dundee Hills see more modest breezes. And wind is a big factor in thickening skins, among other things.
But walking through the vineyards over the years, I realized that there is a distinct difference in humidity too(apologies to anyone in the south, as we don’t have anything at all resembling “humidity” in Oregon during the summer). Walking the rows first at Oracle and Winter’s Hill, and Durant for the last decade, the vineyards are always more pleasant than walking or working at Whistling Ridge or Fir Crest(sedimentary soils). It’s a very perceptable difference, especially if you’re doing something like shoot positioning, leaf pulling, etc.
A lot of the work is done early before it’s too hot, and before breezes kick in. But as the sun gets higher, each vineyard is a very differenct experience, and the cooling effect of having some moisture in the air is quite noticeable. Again-we’re not the south so when I say cooling in reference to higher humidity, I’m not crazy. The difference in the air is most noticeable, between Fir Crest, which gets very hot and drying, and Durant where it’s always pretty pleasant(at the same temps as Fir Crest).
there has been pretty reasonable research on the water holding capacity of the main soil types of the Willamette Valley, and the volcanic soils definitely have a higher potential for holding water. Temperance Hill is the most affected by the Van Duzer corridor, and the breeziest site. But it’s still less dry than Fir Crest or Whistling Ridge. It has distinct wind affected skin tannins, but always more moderate alcohols. While it’s windier and the breeze helps lower the perception of heat, it’s not less humid than the sedimentary sites.