Every year this question concerns many vinegrowers who plan to grow a new vineyard.
The best preparation really starts with uprooting the old vineyard. By doing this you should pay close attention that the old vines and as many roots as possible are removed. Otherwise these will be ideal hosts for virus-transferring nematods.
Especially the widely spread disease of fanleaf is transferred by nematods. The removing of vines and roos is best achieved when the vineyard is uprooted by a specialized plough. Here many roots stay at the old vine and can then easily be removed.
But also ploughing is a good way to remove manually the old roots. After one cartload is done with the deep plough, the roots can then be removed. This is indeed very complex but quite effective and still the only real way to remove the reamining roots after uprooting.
Another positive aspect for ploughing is that it is a way to balance nutrient deficits. So phosphat and kalium can be put into deeper regions of the soil. However, you should consider that these two nutrients are in most cases abundantly in the soil. Therefore, it is recommended to do an analasys of the site before.
In the last years people mainly do without ploughing because it has some negative aspects as well.
- Humus is buried.
- At the site boundary remains a deep channel.
- It can compact or smear the soil at the bottom of its travel
- Time consuming
As an alternative to ploughing it is more and more common to spade. This is similar to spading in the garden but is of course done by machine. The spade is put quite vertically into the soil and it is then floated. By doing this you can achieve depths of 0.45m.
These works should be completed before winter so that the soil can stabilize before it is driven on in spring.