Perennial grass production opportunities and constraints on marginal soils

An increasing global awareness that the supply and security of petroleum-based materials is diminishing, coupled with environmental concerns related to climate change, water availability, and soil degradation, has increased demand for more renewable, diversified, and sustainable systems, of which biomass resources are one of the pillars. Yet, in order to meet the 20% EU renewable energy target by 2020, the demand for biomasses is increasing sharply, thus increasing the risk of conflicts on land use due to competition for food and feed. Therefore, segregating the growth of dedicated biomass crops on marginal land is an option to overcome these conflicts. Therefore, the objective of this work was to determine if producing perennial grasses on marginal soils as feedstock for bioenergy, could reduce greenhouse gas (GHG) emissions without depleting soil nutrients, water supplies, or negatively impacting biological and landscape diversity. This study, funded by European Union (EU), was conducted under project OPTIMA (Optimization of Perennial Grasses for Biomass Production) using Life Cycle Assessment (LCA) and Environmental Impact Assessment (EIA) protocols to identify opportunities and constraints of cultivating perennial grasses, in marginal soils. Results indicate that sustainability of perennial grasses production in marginal soils depends on the productivity. The productivity loss diminishes the energy, and the greenhouse savings but the presence of vegetation may contribute to improve the quality of soil and waters and the biological and landscape diversity. However, a higher land area is demanded to produce the same amount of biomass feedstock and the quality of the biomass may limit its use.