- Planting density and orientation
The planting density is an important issue because it affects both the production quantity and quality as well as the cost of production by impacting the mechanisation conditions. Our appellations require us to have a minimum density of 5,500 vines per hectare, which represents a maximum authorised production amount of 1.3 bottles per vine, which seems excessive for producing high-quality wine. For nearly a quarter of a century, all of our plantings have contained between 6,700 and 7,000 vines per hectare, which allows us to use mechanisation comfortably (1.5 m between rows) and low production per vine, brought back to the legal maximum ranging between 0.8 and 0.75 bottles per vine, although our average target ranges from 0.5 to 0.65 bottles per vine! Under these conditions, we produce between 0.5 and 0.6 kg/m² of exposed leaf canopy, whereas it has been recognised that high-quality grapes can be produced at rates ranging between 1.2-1.5 kg/m² in our region.
Is there any value in significantly increasing the densities? Why not grow 10 or 12,000 plants per hectare? Crowded medieval plantings without mechanisation were much denser (50-60,000) up until the 19th century. The Médoc has average densities of 10,000 vines, for example. Greater density makes it possible to produce less per vine and more per hectare, which certainly improves the potential quality. This very high vine density is well-suited to extremely poor soils, with weak vine vigour and good water availability in summer. On soil that is naturally deeper, as in the case on the entire right bank, and with a higher proportion of clay, high vine density runs the risk of creating much greater individual vigour, which will be only slightly compensated by the increased competition between vines. This increased individual vigour can lead to excessive crowding that is conducive to the development of vine diseases (mildew, grey rot) or problems with shot berries in Merlot, unless the vigour of the rootstock can be drastically reduced; but what about the risk of insufficient water supplies in summer? In addition, the cost of mechanisation is much higher because these conditions require less standard equipment. In the end, apart from the marketing aspect of boasting higher vine density than the neighbours, implicitly suggesting that our production is much higher, I am not convinced of the value of the positive results of such a high increase in vine density at our level, yet, as I have just explained, I do not have a negative opinion on the matter.
The choice of planting orientation directly affects exposure to sunlight. This is therefore a factor that will influence the quality of the grapes. This choice is sometimes simply based on the size or slope of the plot. But in other cases, we must think in terms of the grape variety and soil type. At our latitude in the Bordeaux region, around the 45th parallel north, both exposures are quite possible. The north-south orientation has the advantage of being exposed to the morning sun and having a neutral position when the sun is at its peak, when it is at its hottest, but for a limited time. The east-west position leads to moderate exposure in the morning and greater exposure to the sun in the afternoon and until the sun sets, which results in stronger and longer exposure in summer. It is therefore easy to see that, depending on the depth of the soil, the quantity of extractable water, which produces moderate to high foliage, and whether the grape variety is early or late-ripening, we must choose the most suitable planting orientation wisely and not limit our reflection to the optimisation of traffic patterns for tractors. Foliage management and leaf thinning in particular is handled with this key factor in mind: leaf thinning in east-west vineyards is normally only carried out in the morning to protect the grapes from sunburn.
- Sustainable and eco-friendly training equipment
In our region, the vineyards must be trained using a metal wire frame over wooden stakes. We have always used stakes made of chestnut wood, which last longer over time, and now sometimes use stakes made of acacia wood (split if possible), which is more economical and available locally. Metal stakes offer an interesting, cost-effective alternative in the very long term, yet their carbon footprint is disastrous (4 kg carbon/t compared to 1,000 kg CE/t for galvanised metal). Similarly, the stainless-steel guide wires we used were replaced with galvanised metal, resulting in financial savings and a better carbon footprint (40% reduction in emissions).
All the ties used to attach and train the vines must be made of natural materials (cane, wicker, raffia, recycled fabric): plastic materials are prohibited in Agro-Synergy.