Annual and Perennial Crops for Bioenergy: Soil and Environmental Issues

Perennial and annual crops for bioenergy production are increasing. Much of the biomass and oil used for energetic purpose come from cultivations where bioenergy crops are grown with relatively high inputs. Large amounts of nutrients are removed from the soil with the harvest; and inorganic fertilizers lead to risks of soil water pollution. This chapter reviews the effect of bioenergy crops cultivation on soil chemical, physical, and biological properties. Variation is considerable, soil organic C decreased in most soils under conventional row crops, also, soil N2O emissions are common as a result of the use of N fertilizers. There is some evidence for high leaching losses of fertilizer nutrients and loss of biodiversity. Soil erosion is a problem on newly planted land in many parts of the world. It is concluded that annual and perennial bioenergy crops can both substantially contribute to the supply of renewable energy, but an improved crop management is needed to sustain and improve the resource base on which production depends.