The vine species that we make wine from is called Vitis Vinifera & it evolved in Europe over a million years ago. Vitis Vinifera wants to grow near a creek or river & climb a tree to hang its fruit near the top where the birds nest. This provides a balance of sunlight, water, and the ability to spread its seeds.
In a forest, the soils are dominated by fungi, which help facilitate the breakdown & transport of water & nutrients for the vines and the surrounding plants. Fungi create connectivity in the soil & help the vines to handle extreme weather, drought, and other stressors.
What They Currently Have
Currently, most vineyards are planted in areas more similar to grasslands, and this creates a few challenges for vines. The soils in a grassland are dominated by bacteria and typically have significantly fewer fungi. In an effort to maximize sun exposure, most of the trees in or near vineyards have been cut down, which puts the vines in growing conditions that are very far from what they evolved to thrive in. Adding to this is our addiction to tilling soils regularly, which breaks down the delicate mycorrhizae & other connections that the vines have been able to build with their soil environment. Tilling takes the precious stored carbon from the soil and releases it into the atmosphere, adding to climate change.
The effects of the vines growing in foreign conditions have led to a number of viticultural problems, that we have had to remedy with rootstocks, sprays, soil amendments, and more in an effort to bring the vines some semblance of harmony.
Ways To Bring Balance
It is unrealistic to expect a vineyard owner to rip up their vineyard to look for a forest and a creek to replant in, just to bring the vines closer to their evolutionary comfort zone, but there are ways that they can add balance to their soil that will bring health to the vines.
Let Growing Grasses Lie
Tilling has had such a stronghold in agriculture because it gives a short-term boost to vigor in the soils by breaking down & oxidizing nutrients. This oxidation though is the very thing that makes tilling damaging in the long term. Allowing native grasses, or cover crops to grow all season, then just mow them, helps to leave the soil intact and build it up each year as the roots of the grasses break down. Certain plants when used as cover crops, add nitrogen, phosphorus, and other nutrients into the soil. The other benefit of not tilling is its ability to help the soil grow its water retention capabilities. The more carbon in soils, the more it holds water, tilling takes carbon out of the soil. Also, by leaving the roots of grasses and plants on the soil, they are able to slow the movement of water through the soil, giving the vines a chance to drink when they need to.
One way to accomplish both the goals of increased soil carbon, as well as encouraging fungal growth in the soil, is the addition of wood products. I got to see the benefits of this firsthand when working with James Mantone at Syncline Winery in Lyle. The poor soils on the estate vineyard were desperate for greater water-holding ability, and James decided to spread bark-a-mulch in the vineyard. Bark-a-mulch is the pithy layer in between the bark & the hardwood of a tree. it is a waste product for our local milling industry & so the price was affordable enough to purchase large quantities. Bark-a-mulch is high in carbon, which over time increased the water-holding capabilities of the soil, but it also had the added benefit of bringing a multitude of fungal spores with it from the forest. In a few seasons, it was quite common to see mushrooms growing wildly down the rows of vines in the Spring and Fall. We were also able to see less water stress in the vines throughout the Summer.
Compost, Compost, Compost
If vines were growing in a forest, then there would almost certainly be animals present. The importance of animals being regularly or seasonally around the growing vines is the animals' droppings. Whether it is birds, goats, cows, deer, or other animals, their very valuable droppings add nutrients back into the soil around the vines. These, combined with the ever-present fungi, provide an abundance of natural compost for the vines. Adding a seasonal rotation of animals into the vineyard routine can be a huge undertaking for a winery or vineyard, but there are ways to minimize the needed efforts. Can't you have compost without animal droppings though? Of course! There are however tremendous benefits of adding animal products to a composting regimen. Animal stomachs (especially cows) can break things down to a greater degree for the vines to absorb.
Working With What You Have
Very few vineyards in the world can change their soils and their vineyard practices so drastically as to return to the ideal conditions that vines have thrived in for a million years. The point is not for all vineyard soils to be the same either, the point is to help vines better adapt to our changing climate while making expressive wines that inspire. If you are a vineyard owner and can begin to implement some practices to bring your vines into greater harmony with the soil they grow in, then great! If you are just an enjoyer of wine, like myself, then you can ask the wine shops, wineries, and restaurants that you buy wine from about the practices of the vineyards they work with. Returning vineyard soils to something closer to what vines have evolved to grow in, not only makes healthier vines & more expressive wines but also helps to combat the climate change that is threatening all of us.