Soil engineering: Roussillon’s ultimate balancing act
Roussillon’s 320 days of sunshine a year have earnt it the title of France’s hottest wine region. It has for centuries enjoyed an ideal climate for vine growing, tempered by winds and the influence of mountains and the sea.
In recent years, however, lack of much needed rainfall in winter and spring, coupled with prolonged, intense heat waves in summer, is leaving vine – and pretty much all crop – growers in Roussillon to wonder about the future.
Roussillon’s vines are adapted to dry conditions. The region has a stock of mature and older vines that know to go deep in search of moisture. Its winemakers have a wealth of experience when it comes to sustainable vineyard management, and many are experimenting with new and hybrid varietals. But in recent conditions, and with ongoing hydric stress, vines in some areas are not always able to develop normally or, in extreme cases, to survive altogether.
The lack of water in the soil, and its ensuing inability to regenerate, is what requires focus and innovation.
Finding balance
Agroforestry holds a lot of the cards for re-installing balance in the vineyards. In 2019, Montpellier held the 4th World Congress on Agroforestry, uniting thousands of experts from a hundred countries behind the call for the transformative change needed to ‘make our planet treed again’. The event organized by CIRAD and INRA, in partnership with World Agroforestry (ICRAF), Agropolis International and Montpellier University of Excellence stressed the positive impact trees have on the wider eco-system and their essential role in stable food-production.
As a branch of Agroforestry, Vitiforestry denotes the specific practice of incorporating trees, shrubs or hedgerows into a vineyard. Some in Roussillon have taken to this approach and integrated trees to their vineyards in an effort to reduce soil erosion, create microclimates and boost soil health.
A notable example is Gérard Gauby, at Domaine Gauby near Calce, who planted rows of almond and olive trees between vines, to protect them from the wind but also to attract wildlife.
At Château de Rey in Canet-en-Roussillon, Rémi Sisquelle planted olive, rowan and apricot trees in his efforts to stabilise the ecosystem in the vineyard.
Bringing soils back to life
Another way of improving soil is to directly add organic matter to regulate temperature and lock carbon. The planting and subsequent re-cycling of cover crops to enrich soil is a fairly common practice in many vineyards where organic and other sustainable practices prevail. Cover crops encourage more abundant wildlife and natural balance with predators managing population of pests or keeping undesirables at bay. Once re-integrated into the soil, crops help regulate temperature and bring moisture as well as organic matter to the mix.
A more advanced form of soil amendment is Domaine Lafage’s biochar trial. Biochar was first produced by early populations in the Amazon who covered burning biomass with soil to create a ‘black soil’ with enhanced fertility.
Domaine Lafage makes its modern Biochar using pyrolysis, the burning of plants in a low oxygen environment, a method particularly suitable for agricultural soils due to the higher carbon storage and porosity of the resulting product.
Early results indicate that Biochar can have a positive impact on both soil chemical and physical fertility (e.g. pH & nutrients exchange, porosity, water retention).
More experiments are needed to observe Biochar’s water retention capacity and its ability to concentrate micro-organisms in the soil over the long term. Enhanced vegetative growth in areas treated with Biochar are already showing encouraging results. [View a recent interview of the Lafage team on Wineanorak.com here]
What is certain, is that alongside vine selection, water management and sustainable practices, developing ways of re-engineering soil is key to future-proofing vineyards, in Roussillon and elsewhere.
