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"We need to preserve for longevity what has worked for 2,000 years"

26.10.2021

The dean of the Geisenheim University of Applied Sciences and climate researcher Professor Dr Hans Reiner Schultz expects fundamental changes in the work of viticulture in the coming years due to the effects of climate change. He explained this in an interview with the editors of the European wine platform wein.plus.

"We have to pull out all the stops to keep something long-lasting and sustainable where it has been working long-lasting and sustainable for 2,000 years. That's where patterns of thought have to be changed," Schultz demanded. He is internationally regarded as one of the most important researchers on the consequences of climate change in viticulture. In 2018, for example, he said, the university recorded an average temperature of around 18 °C during the vegetation phase in Geisenheim (Rheingau), which lies exactly on the 50th parallel. "That corresponds to what we measured at the beginning of this century in Santiago de Chile or in Adelaide Hills in South Australia. Both places are on the 34th parallel," Hans Reiner Schultz pointed out.

Drought and dryness now pose a massive threat to viticulture, not only in the European growing regions. Schultz expects a significant water shortage in many regions in the coming years and decades. Therefore, he considers the strategy of many producers to secure their harvest through irrigation to be wrong: "It will soon come to an end in many wine-growing regions, because vines as a luxury good take water away from the necessary agriculture. Irrigation can at most have an intermediate function."

"It is an urgent international task to address research in a collaborative manner"

For him, the most important strategy against drought failures is rootstocks that are resistant to heat and drought. "In research, we need to focus much more on drought-tolerant rootstocks," Hans Reiner Schultz explained. "Almost all rootstocks used by winegrowers today still come from breeding developed against phylloxera. That was over 120 years ago!" he explained. Today, viticultural researchers have to "look at the existing, natural gene pool of grape varieties with molecular biological tools under completely different aspects". However, he said, there are currently only a few institutions working on this. "It is an urgent international task to tackle this research in a network," the climate researcher emphasised in conversation with wein.plus editor Alexander Lupersböck.

The faster breeding of fungus-resistant grape varieties (Piwis) and their large-scale use in the growing regions is also crucial for the preservation of viticulture in the coming decades: "Without Piwis, we will not manage to comply with the EU's Green Deal. The 50 percent reduction in plant protection products stipulated in this deal is a challenge - especially for viticulture, which has the highest consumption of fungicides. In the future, we will need grape varieties with even stronger resistances than today's varieties."

Breeding and research, however, are currently mainly the responsibility of state institutions. In federally structured countries like Germany, it is much more difficult to organise them. "With new strategies, we can - and must - make faster progress. We no longer have 25 to 30 years to breed and approve a new grape variety, as we used to. By then it will be too late," said Prof. Schultz.

"The organic farming system of the present is not the system of the future"

In the course of the changes he expects, organic viticulture could possibly also be given a more important role than it has today: "We know from all the data collected worldwide that organic or biodynamic cultivation yields 20 to 25 per cent less on average. However, in the warm years of 2018, 2019 and 2020, the yield of the organic plots in our trial sites was higher than in the conventionally managed plots. This may indicate that organic systems adapt more quickly. There are also indicators that organic plots produce less greenhouse gases than conventional ones." But organic winegrowers will also have to change their work in the future, Hans Reiner Schultz expects: "The organic farming system of the present is not the system of the future. It must be further developed and adapted. There are endless adjusting screws that we still have to research."

Read the complete interview She here.

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