Cropping systems for biomass production under Mediterranean conditions: implantation techniques and soil carbon balance

The reduction of GHG emission by replacing fossil fuel with biofuel is possible, but the agronomic practices for crop biomass production can have an important effect in the achievement of this objective.In the rural district of Sulcis, in Southern Sardinia (Italy), we evaluated the effect of different implantation techniques of giant reed (Arundo donaxL.) on biomass yield and the effect of different N fertilization levels on soil respiration and soil Carbon (C) balance in the early year of cultivation.In the dairy district of Arborea, in the Central-western coast of Sardinia (Italy), we evaluated the biomass production and soil C balance of maize (Zea maysL.)-based cropping system in relation to the different management of N fertilization sources.The results suggested that, under fertile soil conditions, giant reed can be implanted using the cheapest propagation method (stem cutting) in spring or autumn, while under poor soil conditions, the rhizomes proved to be the best propagation method, independently by implantation season. In the early stages of giant reed growth, compared to the unfertilized treatment, high N fertilization rates determined higher biomass yield, a depressing effect on soil heterotrophic respiration rates and a soil C balance not significantly different from equilibrium.The fertilization with just organic fertilizer reduced the soil C budget in maize-based irrigated cropping systems, in sandy soils under Mediterranean climate.