Assessment of the Potential for Producing Liquid Biofuels from Alternative Feedstocks Grown on Degraded Land and Saline Soils

摘要

It is believed that in the absence of appropriate policies, commercial production of traditional crops for biofuels are likely to target high-quality lands, due to better profit margins and high soil requirements of first generation crops. As a result, a number of studies have started to look at the potential of production on "poor quality soils," based on the argument that biofuels compete with other agricultural land uses only if grown on fertile soil. This paper provides a preliminary assessment of the potential for producing liquid biofuels from alternative feedstocks, grown on degraded land and saline soils. First, it reviews some of the projections for world liquid biofuels production under a business-as-usual scenario, and assesses where they are likely to be grown based on existing policies and incentives. Among the different options for feedstocks production, the paper focuses on planting on degraded land, and estimates this potential in the developing world. Secondly, the paper assesses some alternative feedstock options and best farming practices capable of maximising environmental benefits, with particular emphasis on Jatropha L. and Short rotation coppice (SRC) willow. In addition, the potential of salt-tolerant crops as feedstocks for lignocellulosic second generation biofuels is also considered. Thirdly, the paper presents some initiatives in the developing world, aimed at exploiting degraded land for biofuels cultivation while overlapping social and environmental goals, and stresses the environmental risk of restoring degraded land and returning it to intensive production, particularly where land use is/should be aimed at ecosystem services provisions i.e., biodiversity. Finally, the paper raises several issues of concern for the alternative biofuels feedstocks covered here, particularly when cultivation is combined with high yield production, and concludes that more research is necessary in order to determine which crops and management practices can best minimise impacts and maximise benefits.