Cover crops, or green manure, are an essential agronomic technique in the management of San Polo’s vineyards and fundamental to the winery's production philosophy of absolute respect for the land. Cover crops act as a fertilizer and give vitality to the soil, facilitating the plant’s development. The first step in the process is fertilizing with compost, an organic and completely natural substance. Then, different seeds are sown and each one will give specific properties to the soil. These seeds consist of different plant varieties, combined in a mix tailor-made for the needs of each individual plot. Cover crops consisting of legumes, thanks to their nitrogen-fixing properties, significantly increase the nitrogen content of the soil. When the selected seeds become plants with very deep root systems, they enrich the topsoil with nutrients taken from deeper layers. Another example is graminaceous plants, like barley and rye, which have a bundled root system with shallow development, impoverishing soils which have too much vitality. These plants are often tilled and incorporated into the soil once they flower and since they are rich in fiber they will shift decomposition towards creating “compost” rather than supply immediate nutrients. Brassicas, on the other hand, have a taproot structure. These plants are able to extract less accessible nutrients, like phosphorus, and they also reduce soil compaction.