Threats to any of these elements can lead to lower quality and higher prices.
Winemakers around the world have different tactics for dealing with vineyard disturbances.
One approach is to work with soil scientists. Historically, their role in viticulture has been to map soil types in vineyards, such as volcanic, limestone and calcareous soils.
However, as science advances, winemakers are learning that soil microbes play a monumental role in vine health and wine quality. Scientists, for their part, focus their attention on the community of microorganisms that live in the soil and are called biomes.
We can now see the biological activity and use the information to improve what we want: quality, yield, etc., says Adrian Ferrero, co-founder and CEO of Biome Makers, a company that analyzes microorganisms in the soil.
A healthy soil is rich in organic nutrients. Its fertility is the key to a thriving vineyard.
In the long run, an overview: Soil fertility has been negatively affected by the way we farm, says David R. Montgomery, professor of geomorphology at the University of Washington and author of Cultivating the Revolution : Bringing our soil back to life (W.W.Norton, 2017). Wine production is no exception.
Prolonged temperature increases and drought lead to a gradual decline in organic nutrient content. The result is an unhealthy biome and a decrease in fruit quality and yield.
It’s an evolutionary classic, according to Anne Bickle, biologist and co-author of Nature’s Hidden Half : The Roots of Microbial Life and Health (W.W. Norton, 2015).
Disruption of this sensitive ecosystem means additional stress for the vine. He is forced to produce inferior grapes or die.
The soil biome consists of layers, like an inverted alpine mountain chain. Each layer contains a delicate and biologically diverse community of microbes.
The deeper you go into the ground, the more selective it becomes, explains Nick Weiss, owner and winemaker in St. John’s, Newfoundland. We must let everything live and remain in the order of its horizon as nature has formed it [so that the vine may blossom].
For a long time it was thought that turning over the ground was positive and necessary. It has now been proven that these treatments can be harmful.
I’ve always thought we should go back to the viticulture of 150 years ago, but then people were constantly tilling the soil, Weiss says. Now I know I was wrong.
Mixing topsoil with substrate is not the same as combining raw materials to make cookies. It’s more like chopping strawberries in a blender.
For me, it’s important to have someone else think about the floor, Montgomery says. Over the past century, the industry has learned to think more about tillage methods. We now need to focus on building up the soil and increasing the organic biodiversity in the soil for healthier plants.
These discoveries underscore the importance of the soil biome. Overzealous intervention in the vineyards endangers the production of quality wines. It forces grape growers to find ways to mitigate these hostilities.
However, industry leaders point to a particular type of attack that poses a huge threat to the soil biome and biodiversity.
Climate change, says Marcello Lunelli, head winemaker at Ferrari in Trento, Italy. In particular, the effects of rising temperatures and water shortages.
Drought is considered the most devastating problem of climate change, but dangerous erosion from flash floods caused by heavy rains and high winds has also affected vineyards in regions such as South Africa and Argentina.
In Argentina’s Uco Valley, wind erosion, prolonged heat and drought are destroying the wild flora that surrounds the vineyards.
According to Franco Bastias, chief agronomist at Domaine Bousquet in Mendoza, it drives the dreaded Argentine ants into the vineyards in search of food. They are harmful to the vine and the biodiversity of the soil.
High temperatures have brought into parts of northern Europe pathogens that used to be found only in the Mediterranean region, resulting in catastrophic costs for vineyards. Weiss says Eska, the devastating disease that affects the stem of the vine, is now visible on the Moselle.
Insects such as cicadas, which spread Dore’s disease, are slowly killing the vines in the northern Rhône. The wine growers are now working together on the logging plans.
In La Maison Chapoutier’s vineyard, we treat our vines with warm water, which increases their resistance, explains Michel Chapoutier, Rhône vineyard owner and winemaker.
The microbes in the soil have two tasks: to provide the vine with nutrients and to protect it from pathogens. Synthetic fertilizers and pesticides can manage both, but their use can cause microbial spoilage. This can turn a symbiotic relationship into a competitive one.
Jock Harvey, owner and winemaker of Chalk Hill Wines in McLaren Vale, Australia, says many winemakers in the region treat any threat with synthetic sprays. This overuse threatens the soil biome and biodiversity in the region.
Grape growers in the Texas plains and parts of the US Midwest face the devastating threat of synthetic broadleaf herbicides used to control weeds between rows of crops such as corn, cotton and soybeans.
These chemicals can float for miles around vineyards. The supposed crops are genetically modified to be resistant to the chemicals, but the vines are not, and spraying could kill them.
Science-based education and adaptation can help neutralize these threats. Nevertheless, climate change provides unique conditions that must be addressed each year. Wine growers must remain agile to meet any new challenge that arises.
Success is not so much about a single farming practice – traditional, sustainable, organic, biodynamic – as it is about how it is applied. Successful viticulture requires that winemakers think like nature. Creating a balance in and around the vineyard promotes a healthy soil biome and produces the best fruit.
It’s not just the practice of organic farming and direct seeding in hopes of improving the soil, says Jeannie Povall, owner and winemaker of Botanica Wines in South Africa. It is about understanding what is happening in the soil and whether the soil is balanced enough for microbial life to grow in it.
Understand what happens in soil and whether it is sufficiently balanced for microbial life to develop in it. – Jeannie Poval
Covering the soil between the vines with carefully selected plants, the so-called cover plants, makes more organic nutrients available to the vines. This can help vineyards survive high temperatures and drought stress. Like a sponge, these nutrients absorb moisture and slowly release it back into the soil as needed. It also promotes microbial biodiversity. For example, worms make underground tunnels that act as moisture reservoirs for vines.
When you walk in nature, you never see bare land, says Johan Reineke, owner and winemaker of Reineke Wines of South Africa. For the soil to live, it must be covered.
Proper application of organic compost, manure, plant preparations and fertilizers can further increase soil fertility, which will benefit the vineyard.
Reineke says drought is never a problem for him. This is because steeply sloping vineyards receive too much rain, leading to erosion. This is harmful to the vines because it destroys the nutrients in the soil and breaks down the layers of the biome.
To counteract this during the rainy season, cover crops are planted between the rows of vines. It also encourages the growth of local fynbos to help sustain the soil.
As droughts have become more frequent around the world, wine growers have become more aware of the importance of water.
In Paso Robles, California, Dow Vineyards maximizes water use by limiting the water supply to the vines, which some say improves fruit quality. However, the intense heat of 2017 and 2020 proved too much for the vines. Dow decided to water rather than risk losing entire vineyards.
During the Dow’s heat peaks, short sprinklings twice a week keep the soil moist. The tissue is also used to protect leaves from sunburn, and compost and manure activate soil microbes.
These measures help stressed vines survive.
Ferrari monitors soil moisture with high-tech probes in the soil. The vines thus receive the ideal amount of water, which benefits the health of the soil and the vines. According to Ms Lunelli this gives an even clearer expression of the terroir in her wines.
Threats to the soil biome and to biodiversity can be mitigated by good practice.
When Craig Camp, COO of Troon Vineyard in Oregon, arrived in Applegate Valley, Oregon in 2016, the soil was in terrible condition after years of poor farming practices. After careful soil analysis and the introduction of biodynamic and no-till methods, Troon’s soil biome is being restored.
The general awakening of the microbial community and the diversity of conditions throughout the property are striking, Camp said. In addition, the clear improvement of the health of the vine and the quality of the wine is the ultimate goal.
Maximum microbial yield
Anna Bickle, biologist and co-author of The Hidden Half of Nature: The Microbial Roots of Life and Health and David Montgomery, professor of geomorphology at the University of Washington and author of The Growing Revolution : By bringing our soil back to life, we destroy the basis of a healthy biome.
The solidarity community consists of three guilds:
Corrosive fungi and nitrogen eaters extract nutrients from the soil that are not available to the vine. They turn them into food for the vines.
- The exudates act as a force field that protects the vine from the pathogens that threaten it.
- A recipe for a healthy biome is full of useful insights for the community: Minimal soil disturbance.
- Keep live plants in the soil at all times, avoid bare soil and integrate carbon and organic matter to feed the microbes.
- Maintain plant diversity in the soil through cover crops and surrounding areas. This promotes the diversity of exudates and microorganisms to form a strong community.
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