The chemical analysis of the soil is carried out at least every ten years: once the necessary nutritional elements have been identified, they are supplied with an adequate fertilizer – preferably organic but, in any case, approved and permitted by sustainable forest management systems. If the soil analyses show any mineral deficiency, a targeted fertilization cycle must be performed, limited to the planting period and the first three to four years of the cycle. Sub-irrigation, which reaches the roots in a more targeted way, also reduces the use of water and fertilizers.