The vines and the soils need it ! This year we will sow some grass, and some vegetables on the vines. The advantages of the vegetables is that it takes the nitrogen of the air to give it to the soil. The nitrogen isn’t animal nitrogen but mineral. The vines need every years nitrogen, that’s why we are trying to find some for it naturally. The second advantage of the vegetables and of the grass is that they allow the roots of the vines to go deeper and deeper to give them energy, life and water at higher “ratios”. That’s only a winter work, after we’ll destroy what we sow to avoid the concurrence between the grass and the vines.