Building resilient vineyards

By Jamie Goode | 8th March 2022

One of the largest changes I’ve seen in the world of wine over the last five years has been changing views on how vineyards should be farmed. This is largely prompted by the realization that our climate is currently in a state of chaos, and vines are among the most sensitive crops to changing weather patterns.

It has been the norm to refer to ‘climate change’ or ‘global warming’, but I think the term climate chaos is better, because it describes the situation more accurately and also adds a sense of urgency: this is no ordinary problem. It’s a big deal.

The viticultural scene worldwide is particularly vulnerable to shifts in climate and also chaotic weather patterns. This is because each grape variety is only able to function really well in quite narrow climatic ranges. And some varieties are more fussy than others. South Africa’s wine lands show this really nicely. Pinot Noir only really works well in cool spots like Hemel-en-Aarde and Elgin. Chardonnay has a broader range, and does really well in these two regions, but can also excel in Stellenbosch and Robertson, which are quite a bit warmer. Cinsualt likes the warm, and does really well in the Swartland; Chenin Blanc can do well here too, and also in Stellenbosch and Paarl. In the relative heat of Franschhoek, Semillon and Syrah seem to step up to the plate.

If climate chaos was just a matter of a warming trend, then it could be planned for: grape varieties could shift their range, and new vineyards could be planted in regions that were previously too cool, for example because of altitude. But it’s the chaotic nature of the climate, where some of the predictability of seasons has been lost, that’s causing the real problems. For example, from 2016 onwards there were four years of drought in South Africa’s winelands, and reservoirs were empty. Some seasons are wetter than normal; others drier. Some are cooler; many are hotter. In order to combat this unpredictability, it’s necessary to create vineyards that are more resilient: vineyards better able to adapt to seasonal changes.

This is where the science of agroecology comes in. This is treating the vineyard as an ecosystem, building biodiversity and farming soils, not just thinking about the vines. It’s at the basis of a new way of farming called ‘regenerative’. And a lot of South Africa’s top viticulturalists are thinking about how they can work this way in the conditions they face. One of the fathers of agroecology is a Chilean-born researcher who works at the University of California, Berkeley, called Miguel Altieri.

This is how Altieri describes his research focus:

‘The thrust of my work has been the development of the science of agroecology, which is defined as the application of ecological concepts and principles to the design and management of sustainable agroecosystems, providing a framework to assess the complexity of agroecosystems but at the same time the tools to develop environmentally sound, socially just, culturally diverse and economically viable solutions to problems inherent to the industrial model of agriculture. This science has been nurtured by advances in modern agricultural science and also by elements of traditional farming knowledge. In a sense agroecology has become a bridge that promotes the dialogue of western science and traditional wisdom.’

On my last visit to South Africa I spoke to two winegrowers who were both busy trying to make their vineyards more resilient. Both are working in the Swartland, a warm region that has suffered a lot in the recent drought. The first was Eben Sadie, who agrees that climate change is a problem. ‘It has been a major topic,’ he says. ‘There are definitely areas in the world that are more prone to be affected. Look at areas in Australia, and here in the Swartland. These places that are already warm and dry will be the first to face the full wrath of the storm.’ He reckons that the key thing in the light of climate change is to farm well to protect resources, and to be sustainable. ‘One of the reasons I love the Swartland is not the lack of water, but because it is not a vastly irrigated area,’ he says. He showed me a vineyard that he planted a few years back. ‘This vineyard isn’t irrigated and it was planted in the height of the drought,’ he says. ‘The biggest drought in a century. It is now four years old and it has only known the drought.’

One thing he is doing differently is planting the vineyards completely square, in a sort of grid, so there are no fixed rows. The vines are bush vines at low density. ‘The beauty of planting square is that you can cultivate in different directions,’ says Eben. This means that if he needs to put a tractor in the vineyard, it isn’t always going down the same row, compacting the soil. He’s also moved away from pesticides and herbicides. He plants cover crops to compete with the weeds. ‘In the early stages of summer we use a quad bike to roll the weeds, to avoid compaction. It creates a criss-cross carpet. This brings the evaporation down. It also moderates the soil temperature which is good for plant growth and microlife. After the season, we put compost on top of this, and it’s a great seed bed.’ This year Eben planted triticale, barley, wheat, white and yellow mustard, lupins and fava beans.

Plantings are low density, which suits the warm climate. ‘There is a place for high density, but with our water and hydric stress it might not be the best option,’ he says. He’s also not a fan of trellises in the Swartland. ‘We’ve only been trellising for 100 years. I’m more inclined to trust the past 6900 years. If you put this on a trellis system in our climate it increases your foliage spread. The only thing you put up on plates like that is solar panels. You capture a lot of sun, a lot of energy. But you must do something with that energy. You need more water and nutrients. I don’t view this as sustainable over the long term.’

The second grower is Chris Mullineux, who I visited at his Roundstone farm that is home to Mullineux wines. He showed me a block of Grenache Blanc, which was planted from cuttings taken from an old vineyard in the Picketberg. ‘We didn’t plant these vineyards,’ says Chris. ‘We only took over this farm in 2014.’ Originally, the vineyard was trellised, but the vines were quite small, so the Mullineuxs were able to cut them down and retrain them as bush vines. ‘In the Swartland we prefer bush vines,’ says Chris. ‘The vines are smaller and the yields are smaller, but what we really like about them is that they give a bit more shade to the grapes.’

He doesn’t use any herbicides, but instead grows cover crops and uses mulches. As far as possible they try to match the cover crops to the site. ‘Here on Kasteelberg it is much more cover crops that assimilate carbon, such as wheat and oats,’ says Chris. ‘The soils are relatively nutrient rich. We want to build structure and organic matter in the soil to hold moisture for the vines. In the Paardeberg it is the opposite: the issue is more nutrients because the soil is sandy and poor, so there we plant cover crops like fava beans and lupins that assimilate nitrogen.’

Some of the Syrah vines they inherited were 15 years old and had developed thick trunks. To de-trellis them in order to turn them into bush vines, as they have done with the Chenin and Grenache Blanc, would have resulted in large cuts that might expose them to trunk disease. So they have kept the trellis but allowed the canopies to sprawl. They tuck the main shoots in, but not the side shoots. This helps give the grapes partial shade, which keeps their aromatic complexity in this hot sunny region.

Using mulches and cover crops has made the soils better at retaining water. Before 2014, they were just buying the grapes from this farm, and the owner was using supplementary irrigation. ‘He was irrigating 6-8 times a season,’ says Chris, and this was a couple of years before the big drought kicked in. Since they took over the farm, they have been planting cover crops and mulching. In the 2019/20 growing season, the fourth of the drought, they didn’t have to irrigate the block. ‘It is incredible to see how organic matter is helping,’ says Chris. ‘When we first took over the vineyard you couldn’t take a nail and hammer it into the ground. That is how hard and dead it was. Now, you can see how soft the soil is: it takes three or four years and you can turn it around.’

They have also broken the vineyard into blocks or corridors, and then in between have planted sections of fynbos. ‘This is fynbos that grows on the mountain here. 90% of it is indigenous to Kasteelberg. We went to a local nursery and they took cuttings from the mountain, rooted it out with hormones, and then we planted it. This was planted at the same time as the vines. The idea is that this is a home for wasps and ladybirds to nest, and then they come and feed in the vineyard on aphids, mealybugs or anything that is growing there. It helps to keep the natural balance.’