Sunday, 11 October 2015 15:00

Dry farming success

Written by 
William Hoare. William Hoare.

Dryland farming is not that easy for grape growers in New Zealand. But one company in Marlborough has had success, although it hasn’t been achieved overnight.

Fromm Winery began its conversion from irrigating to dry farming back in 1999. These days 60 percent of the vines are not irrigated, with some of the older blocks having not been irrigated since 2004. Water savings are calculated at 9.5 million litres a year. (Irrigation lines are still present, even if they are not used.)

Fromm General Manager William Hoare says once they made the decision to move away from irrigating, it has been a 10-year process. Initially all the young vines planted are irrigated, to allow them to grow in balance and not be stressed. 

“We aim for the square metres of leaf to be the same as the square metres of roots. So we get them up, get them strong and then we look at irrigating the vines in the same way as rain.”

That means gradually weaning the vines off daily irrigation, and watering only every two or three weeks - depending of course on the season - for about four to six hours.

“We irrigate in such a way that the vine’s roots have to work to go after the water. We even went to the extent of changing the times each day when the vines were irrigated – this way they don’t rely on their 10 am feed. We have dug holes two and a half metres deep and the roots down there are the size of your fingers, big tap roots.”

It is not something you can decide to undertake tomorrow, not unless you want to stress the vines out he says.

“Vines are just like people - if you stress them out, they won’t work.  A stressed vine makes really tannic and bitter wines. If you are looking at dry farming, you need old vines and you need to have grown them so the roots have travelled well down.”

William says when French soil scientist Claude Bourguigon visited the vineyard four years ago he made an interesting comment that made sense to the Fromm team.

“He said that with new world wines, where everyone irrigates, the roots don’t have to go looking for water, so they stay in a ball under the dripper. That means the vines make varietal wines, pretty wines, but they can be quite simple. Whereas if you dry farm you try and get the vine roots to go deep. Then the vine has to suck moisture from deep within the soil which makes the wines taste of that site. That helps make each of those wines special and that can be the difference between a really good wine and a great wine.”

While most varieties will benefit from dry farming, William believes you need to be careful with Sauvignon Blanc.

“... because if you stress Sauvignon Blanc you end up with much more of the tropical, pineapple characteristics coming out. They end up looking a bit more like Hawke’s Bay Sauvignon, rather than the typical Marlborough. You can get an incredibly concentrated aromatic, but it will be different.”

Fromm Winery has a strong organic approach when it comes to its vineyards. But that doesn’t mean it has abandoned science. William says they now do more testing for nutrient and moisture levels than they did prior to stopping the irrigation. And thanks to a steady compost and mulch regime, the nutrient levels along with moisture levels have been almost perfect according to tests taken. 

Perhaps the biggest test was this recent season, which was an extremely dry one. While the older vines coped well, the younger vines, which are still being irrigated, didn’t fare as well.

“We have six-year-old Riesling in front of the winery, which we have been irrigating. But this year it got stressed, the base leaves went yellow, and we had issues with potassium and pH levels, which for a winemaker becomes a hassle. While this didn’t affect the finished wine, it’s a hassle for the winemaker to manage through the winemaking process. The vines we hadn’t irrigated though were totally fine. The root systems were big enough that they could get what they wanted, when they wanted it and the wines look really good. 

“What seemed to happen was we would irrigate those young vines, then they would dry out, so we would irrigate again. But the vines began to stress, because we couldn’t get the water levels quite right. It is a guessing game in conditions like that.”

It makes perfect sense that vines, like most organisms, are lazy. They do only as much as they need to to survive. So if the water is being delivered on a daily basis, the roots will stay close to the surface, getting everything they need without having to dig deeper.  Gradually remove that source of water and they will have to work for what they require, in the end creating a stronger, more balanced vine. That balance is something William says is apparent in dry farmed vines, when it comes to canopies. 

“We only trim them once, maybe twice a year and they have that nice balance where the growing tips are healthy but you are not dealing with big canopies. Leaf plucking is easier, trimming is easier and the actual canopy is easier because it is not being pumped up artificially.”

In terms of advice, he says if you are considering moving towards dry farming, take a good look at your soil type, your root stock, what wine style you are trying to make and the age of your vines.

“If you have older vines, and by that I mean 10 years or older, it is a positive. I would get soil monitoring to measure the humidity in the soil. And then go slowly. Don’t just randomly do it. It has taken us 15 years to get the vines to the stage where we don’t have to irrigate them. It cannot be done overnight.”

 

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