If you’re feeling a bit parched on a hot summer’s day, just imagine how thirsty the vines can get when they stand out in the hot Marlborough sun day in and day out. On the face of it, the idea of withholding irrigation from them seems downright cruel.
But it’s exactly what our Marlborough viticulturists are doing. Not out of cruelty (they love their vines), but with the twin objectives of saving water and improving our wine.
“We believe people may have traditionally over-watered the vines,” says David Bullivant, Marlborough Area Viticultural Manager for Babich. That is why Babich volunteered our vineyards for a trial run by NZ Winegrowers. This placed Babich at the forefront of this research in New Zealand.
What happens in most of the New Zealand wine industry is that viticulturists measure the moisture in the soil, and then when the levels get too low, they irrigate – mostly by drip irrigation delivered near the foot of each vine.
“We’ve become much smarter with this over the years,” says David. “On most vineyards, they would irrigate long and deep if the soil has good water-holding capacity, for instance clay soils. Where the soils are more stoney and free draining, we need to water small amounts and often, otherwise the water simply drains right through the soil profile.”
However, he believes further improvements are possible.
One of the breakthroughs is not to measure the water in the soil, but in the vine itself. Using a device they call the “pressure bomb”, our viticulturists measure the pressure of water in the vine, a bit like measuring someone’s blood pressure. This gives a more accurate indication of the level of water stress the plant experiences.
During the ongoing irrigation trials, the trial area only received irrigation when the water pressure in the vine dropped below given thresholds. In the 2018/19 season, this meant that the vines in the trial received less than 50% as much water as their neighbours, who were watered using current industry standards.
“This had a number of impressive benefits,” says David. “For one thing, we saved a lot of water.”
This is great for someone like David who is passionate about our natural resources – water preservation in itself, but also benefiting aquatic life and giving Kiwis the opportunity to enjoy our waterways more.
“This is something of a crusade for me,” admits David.
“In terms of managing the vineyard, we also saved cost, as the drier parts of the vineyard had fewer weeds we had to control. As for the vines, we didn’t have to crop-thin or leaf pluck as much.”
The eventual crop load was higher than from neighbouring vine rows, the berries were smaller and sweeter.
“Our winemakers preferred the wines from the drier vine rows, especially the Pinot Noir. Our senior winemaker, Adam Hazeldine, said the wines from the drier rows showed more density, plushness and complexity.”
After two years, the trial results point at the possibility to do dry farming, i.e. not irrigate at all.
“We’re not there yet and it may not be suitable for all sites, but it is something we definitely want to try at some of our Babich vineyard blocks in future. With less irrigation, there is more incentive for root development. With better root systems, the vine is able to find water further afield. It makes them more robust, able to better withstand the droughts we experience in Marlborough. At the same time, it creates opportunities for the vines to pick up minerals that can be reflected as extra complexity in the eventual wines.”
So, when you feel like a drop in a year or so, the Babich wine you choose may be even more flavourful than what we have now!