Accelerating the Rate of Crop Yield Gains to Ensure Sustainable Biofuel Systems.

High petroleum prices are driving a rapid expansion of global biofuel production capacity from starch, sugar, and oilseed crops. While second generation biofuels made from non-food crops are under development, large-scale commercialization is at least 7-10 years away. In the meantime, biofuel production capacity from food crops will likely build out to a point where crop prices reach levels that make further investment in additional biofuel plants unprofitable. Given this situation, current rates of yield gains and available land for crop production are not adequate to meet demand for human food, livestock feed, and biofuel. Either crop yields must accelerate substantially on existing farm land, or crop production area must expand into rainforest, wetlands, and grassland savannas. At issue is how to accomplish this yield acceleration while also protecting soil and water resources and achieving a net reduction in greenhouse gas emissions. In some major grain-producing regions, yield advances will stagnate as average farm yields begin to approach the genetic yield potential, which in turn has increased little in the past thirty years. A global analysis of the major food crops used for biofuel production will identify those regions where yield stagnation is most likely. We will argue that biofuel production from food crops will not be sustainable without a major coordinated global effort in research, technology development and education to close the gap between current average farm yields and yield potential, and to raise yield potential itself, while preserving environmental quality. Although the magnitude of this scientific challenge has been grossly underestimated, it is possible to achieve the degree of ecological intensification required to ensure global food security in a biofuel world.