Soil fertility and its organic functions are maintained and bolstered each year by rotating durum wheats and pulses, ameliorative crops par excellence. Their roots capture nitrogen in the air and turn it into organic substances, thanks to the presence of certain microorganisms, in symbiotic coexistence with the plant's root structure, thus guaranteeing optimal production. The burial of crop residues encourages the mobilisation of low-mobility mineral elements such as phosphorous and potassium.