Before planting a plot of land we let the soil rest for a few years, giving it chance to regenerate and purify itself. It is important to ensure that the roots of the previous vines are all dead, so that they cannot act as a medium for disease-carrying micro-organisms. As for the choice of grafting stock, we prefer low-yield varieties with roots which drive deep underground, wherever the soil conditions and vine variety concerned will allow it. Such graft stocks develop strong root systems in the porous layer below where hydrocarbons form, and are efficient in extracting its mineral content. This contributes to the "soil effect", i.e. making a wine which expresses its own particular soil type. We currently choose graft stocks 161-49, Gravesac or 3309 in preference to the more traditional variety S04, whose presence on our vineyard is being reduced regularly.
The density of planted vines is increased, while still allowing certain operations to be mechanised.
We are careful not to plant rows too close together. This allows the machines to pass through easily, aids the circulation of air, avoids the danger of those diseases which can develop when rows are too close to each other, and above all gives the vines a clear view of the sun.
The most recently planted vines of the Grands Crus Kirchberg and Osterberg are planted at a density of 6250 stocks per hectare.
For the remainder of the vineyard we have chosen a density of around 5600 stocks per hectare. We follow the principle that for a given quantity of produce it is better that the fruit comes from as many individual vine stocks as possible. The fewer grapes each vine stock produces, the greater the chances of obtaining concentration. The variable that we regulate is the distance between stocks in the same row. At present the width of the rows is fixed according to the soil conditions at between 1.50 m for Grand Crus varieties, and 1.60 m to 1.70 m for others.
In winter 1999 we returned to working the soil with the plough. This practice has been somewhat forgotten for several years, but recent studies have shown it to be important for the soil's microbial life, which is itself a major contributor to creating a wine which expresses the soil. We wanted to avoid using decompacting machines for this first process - consisting of ploughing to a depth of 15 to 20 cm - so as not to adversely affect the vines' root systems.
On all the plots of land where it was possible to plough, the work was carried out on just one row in two.
The other row was left grassy. We chose a system of natural vegetation management which consists of regulating the natural level of vegetation by scything, after a maximum number of flowers have blossomed. We preferred this form of plant cover to artificial plant cover because it allows a wide diversity of species to thrive on the land, and so avoids the situation of having just two monocultures - the vine and the plant - living side by side. It is important to conserve a certain biodiversity in the vegetation, which then makes an excellent biotope for numerous insects. Some of them, like the ladybird, prey on insects which destroy the vines.
The height of plant cover and the way it is nurtured do have an effect on the quality of the future harvest. The height should be adapted for every plot of gound, to suit the productive strength of the vines there, and the type of wine to be made. Plots of land which are set to produce late harvest wines ("Vendanges Tardives") and superior grape selection wines ("Sélections de Grains Nobles") are defined in the winter, and the vegetation is cut accordingly. The aim is to produce the very low yields per vine which are necessary for achieving wines of great maturity.
Our choice of phyto-sanitary treatments are veering more toward informed combattive techniques. We have been certified according the TYPLO specification for the 2003 to 2007 vintages. This specification is recognised by the Organisation Internationale de Lutte Biologique et Intégrée. As from 2005 we started in parallele a certification in organic farming.
In the spring/summer of 1999, for example, we kept a regular population count of the spieces of butterflies whose eggs become vine-eating caterpillars, and so were able to evaluate the level of risk they posed. Counting allowed us to avoid one treatment process altogether, and to target a second one solely at areas where it was needed. Accurate knowledge about the population size of vine-eating insects brings the added advantage of allowing the use of products which are more specific to the situation, and more neutral on the environment.
In 1999 all of our vines on the plots devoted to the Grands Crus Kirchberg and Osterberg were protected against grape worms for the very first time by a technique based on sexual confusion. This technique consists of filling the air with the odour molecules the butterflies use to locate each other prior to mating.
If the insects cannot meet, the females cannot lay fertilised eggs, and therefore cannot give birth to caterpillars which would eat into the fruit. No synthetic fertilizer has been used since 1995, so as to limit the productive strength of the vines, and to force them to seek their nutrients in the deeper soil. Only a small amount of plant compost was used in 1999 on certain plots of ground which lacked humus.