Control of fertilization and crop interventions through the creation of vigor maps

Château Couhins is a Graves Cru Classé located in the outskirts of Bordeaux, in Pessac Leognan area. It’s belong to French National Institut for Agricultural Research (call INRAE). It cover 32 hectars and the estate opted for high quality, environmentally friendly viticulture.
The château is the showcase of INRAE, a place for the production of a Grand Cru Classé from Graves and a demonstration site for the latest innovations from research. Two-thirds of the vineyard is dedicated to red wines (Merlot, Cabernet, and Petit Verdot). The remaining third consists of white ‘Crus Classés de Graves’ (Sauvignon Blanc and Gris).
The wine production of Château Couhins is certified in organic agriculture since 2022. Since 1999, Château Couhins has used neither herbicides nor insecticides and manages its inputs carefully.
Château Couhins prioritizes careful consideration and observation of the vineyard plot by plot and use digital solution for this objective before deciding on any treatment.

The Château Couhins team has been mapping the vigor of each plot on the estate, enabling him to generate intra-plot zoning and adjust fertilization according to the needs of the vines.
They use the Aerial Imaging solution to produce vigor maps once a year and those maps allow them to zone their plots of land.
This zoning and the Know-how of the technical team allows them to produce different treatment recommendations for his tractor drivers and thus adjust the dose of fertilizer and green work.

Farm challenges

Producing perfectly ripe grapes requires a balance between leaf and grape growth on the vine. Château Couhins’ strategy is to practice precision viticulture, taking this leaf area management into account and adjusting its inputs and practices accordingly.

The objectives are :

• to adapt organic fertilization to the vine’s needs, applying only what is necessary in the right place. This aims to reduce inputs and use them only when necessary.
• to optimize cultivation practices throughout the season based on leaf area to achieve the best ratio between leaf and grape growth and optimize allocated time and resources.
• to reduce/improve vineyard heterogeneity.

Assistance / Boost program

Château Couhins did not benefit from any program to implement this project.

Innovative features of the initiative / solution

Once a year, The Château Couhins team is mapping the vigor of each plot on the estate using ultra-high resolution aerial imagery and data insights. They rely on a company specialized aerial-based spectral sensors and a cloud-based image processing service which produces a visual and statistical representative of vigor variability from EVI (Enhanced Vegetation Index) measurements.

Enhance Vegetation Index (EVI) is a ratio of hom much sunlight is reflected off the plants in different colour bands, including infrared.It is used to measure vigor. It is less dependant on the time of day at which the image is taken, less dependant on dhadowing or soil variation than the NDVI.

It give a detailed vigor maps and a granular plant-level resolution of isolated canopy data. Using this data, they identify plot with varaibility and use these map to break up zones for cultivation where inputs and cultivation practices will be adapted to the specific needs of the vines:

Organic soil fertilization is modulated using intra-plot zoning.
Soil maintenance practices and cultivation practices to vines is allocate strategically with high, medium and low vigor.

Results obtanied

The use of NDVI measurements in the form of vigor maps has allowed us for more than 10 years to very precisely guide, on the one hand, our choices of harvest dates and intra-vineyard selection, and our vine management and soil maintenance practices based on vine vigor on the other hand. The main result of using this technology for us is greater adaptability to an increasingly changing, variable, and complex context. In the vineyard, the use of vigor maps and remote sensing has thus allowed us to adjust our management choices to increasingly severe abiotic constraints (droughts, heat peaks), resulting in better resilience in the face of current climate disruption. Thus, while being certified organic, we manage to achieve yields equal to or even higher than the average of neighboring estates in the PDO, while producing wines of a quality consistently recognized by international journalists (A. Galloni, Y. Beck, E. Lister, J. Suckling, etc.).

Analyses of soil microbiology now available should allow us to confirm the positive evolution of the vitality of our soils enabled by this precision viticulture approach.
In the winery, the use of vigor maps quickly allowed us to make progress in the precision of our great white and red wines, particularly in selecting the grapes best suited for making long-aging wines. At the same time, we were also able to make progress in developing new cuvées with an organoleptic profile adapted to new consumer expectations (lighter, fruitier, fresher wines).

Lessons learned

The use of vigor maps has taught us to value the heterogeneity of our vineyards by giving us the ability to understand it objectively. The possibility of adjusting the doses of fertilizers or plant protection products, or of applying differentiated pruning or leaf-thinning instructions, allows the various employees and operators to improve in their work and develop their skills. The opportunities offered in terms of precision viticulture undeniably contribute to the development of our different team members.

Contact

• Website: https://vineview.fr
• Zacarie Kerrim: zacarie.kerrim@vineview.com

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