Effects of management choices on the ecological impact of biofuel crops

Background/Question/Methods

Bioenergy crops are often classified (and subsequently regulated) according to species that have been deemed environmentally beneficial or detrimental, but in practice, management decisions determine the overall environmental impact of a bioenergy cropping system. Although competition between food and fuel crops can exacerbate the environmental impacts of bioenergy, key management decisions can mitigate or reverse those impacts. I will introduce and review examples of this “management swing potential” in both temperate and tropical regions.

Results/Conclusions

Prior land use, harvesting techniques, harvest timing, and fertilization are among the key management considerations that can swing the environmental impact of a bioenergy cropping system from negative to positive or the reverse. Although the management swing potential is substantial for many cropping systems, there are some species (e.g. soybean) that have such low bioenergy yield potentials that the environmental impact is unlikely to be reversed by management. High-yielding bioenergy crops (e.g. Miscanthus, corn, sugarcane, and fast-growing tree species), however, can be managed for environmental benefits or losses, and the bioenergy sector would be better served by adopting a management-based classification of feedstocks rather than the current species-based classification.