Terroir study boosts Loire quality push

Loire grape growers are being urged to take advantage of a free, in-depth vineyard mapping resource, designed to help producers maximise the quality potential of their sites.

Etienne Goulet of InterLoire compares soil samples at Domaine de la Noblaie in Chinon

Funded by InterLoire, the Unité Terroir de Base (Basic Terroir Unit) programme saw researchers take two soil samples per hectare across the region to create a map capable of showing factors such as the bedrock, soil depth and drainage for individual plots.

From this geological base it is now possible to advise growers on viticultural factors such the location of earlier ripening sites and the most suitable rootstock to use in each vineyard.

“No other region in France is doing it at this scale,” said Etienne Goulet, technical manager for InterLoire, of the initiative, which was completed for the Loire two years ago. Any grower or student can now access the maps for free from their local town hall, or search the Techniloire website’s “e-terroir” link.

Although terroir analysis is becoming increasingly detailed in many parts of the world, such as McLaren Vale’s Scarce Earth project and the Barossa Grounds initiative, this Loire programme goes well beyond sub-region to offer a picture of individual plots of land.

“When growers have this level of resolution, they can manage their practices change their practices, make a special cuvée or blend different cuvées to increase complexity,” outlined Goulet of the potential applications for such a detailed information resource.

Among the first producers to take advantage of the scheme was Jérôme Billard, who took over Domaine de la Noblaie in Chinon from his father in 2003. With the mapping project not yet complete at that time, he commissioned and paid for the same in-depth plot analysis across his own 24 hectares at a cost of €200/ha.

“It’s maybe the cost of one spray,” said Billard as he emphasised the far more valuable return on investment he has been able to enjoy as a result of such a detailed picture of his vineyard.

“At first you understand nothing, but after two or three years when you have different vintages then you start to really understand,” he remarked. “All our wines start with that study.”

Among the most important benefits for Billard is the recognition that “there’s not a good soil or a bad soil; it’s important for me to understand the best kind of wine I can do here.”

He also highlighted the resource as a particularly valuable tool to support the estate’s conversion to organic viticulture, explaining, “it was really important to understand how the soil was working and how the roots were absorbing food.”

To illustrate the effect of this mapping on Noblaie’s wine portfolio, Billard remarked: “When I took over there was one red, one white and one rosé; now we have four reds, two whites and two rosés, including one sparkling.”

What’s more, he continued, “We now do three wines from the same block. The bottom of the slope has much more food and water and the soil is deep so all the vines at the bottom are for sparkling wine and rosé. We have early picking and prune later because in springtime we can have frost at the bottom. It’s interesting because for my father that block wasn’t good for wine, but we can make something very nice.”

Goulet shows off a map depicting the most suitable rootstock to be used in different plots

The availability of such a detailed picture is particularly helpful in a region where chalk, clay, gravel, flint, sand and, to the west in parts of Anjou, schist, all feature in proportions that can vary considerably from one metre to the next.

“Most growers understand there are good soils and bad soils, but that is not the way of this tool; the aim is to show different soils,” explained Billard.

Despite the resource’s free availability and positive reports from growers, Goulet pointed to the results of a survey carried out three years ago by InterLoire, which suggested that just 25% of Loire growers were using this tool “regularly”. However, he also noted that many vineyard consultants draw on the information available, thereby extending its reach still further.

“It’s a fantastic tool we have here in the Loire Valley that is not used enough,” asserted Billard. “When you have this kind of tool you can adapt every project. It’s a base you can put lots of things on. I do not understand why not so many people use it – for that kind of cost you’d want to do it everywhere in the world. For young guys with no knowledge of their vineyard it gives a base to work on.”

He suggested that uptake of this resource was most prevalent among producers with higher ambitions for their wine, saying: “That kind of tool is interesting for people who do more in terms of quality. You have to be sincere in what you are doing.”