Soil. We take it for granted don’t we? How often do we think about soil?
Grape growers in the business of making good quality wine are thinking a lot about their soil.
Soil varies from place to place. It’s a part of what the French call ‘terroir’. Inextricably linked to a place.
There are two things to bear in mind with soil; soil texture and soil structure. They are quite different but easily confused. Put simply, soil texture is the size of the particles and soil structure is the way in which those particles bind together.
Think of the difference between a clay soil and a sandy soil.
The particles in a sandy soil are quite large. Water flows through sand easily and it doesn’t retain water. Vines grown on sandy soils tend to produce light fruity wines. Sandy soils drain well.
The particles in a clay soil are tiny. Much smaller than the particles in a sandy soil. They bind together and hold on to the water. Clay soils are generally colder and moister than sandy soils so grapes may take a little longer to ripen and budburst may be later than in a sandy soil.
Why would budburst be later in a clay soil than a sandy soil? Well budburst occurs when the vines come out of dormancy (generally after around 10 days with the temperature being more than 10°C) but also the temperature of the soil makes a difference.
Of course soil needs to be looked after too. it’s easy to damage the ‘structure’ of the soil by running heavy machinery over it when it’s wet. What we want is a soil that’s free, that you can crush in your hand, that’s full of organic material.
After all, when we plant vines, we hope they’ll be around for a long long time. Vines are not rotated with other crops that bring life and nourishment to the soil. It must be looked after.
I took the soil picture yesterday while walking in the vineyards. The parcel is called Les Granges and is owned by micro-vignernon Michel Autran who makes just 10,000 bottles a year.
Rich and free, it’s looking fantastic with tons of organic matter. It’s a living breathing soil that will nourish the grapes well. The recent cold weather broke up the structure nicely. It’s a soil that’s heavy in clay so the frost freed the particles nicely.
Last year soils like this were much harder to work as the heavy rains and then dry weather without a cold spell lead them to set like concrete.
Growers are out ‘working their soils’ at the moment. Turning over the soil underneath the vines so it’s aerated and suffocates weeds naturally without having to resort to chemicals.
I’ll post a picture of a less happy vineyard this week so you can see the difference.
