Biofuel Crop Yields Often Overestimated, New Study Suggests

Scientists and biofuel manufacturers alike have been optimistic about the potential of food crops to produce energy, but a new study by researchers at the University of Wisconsin-Madison and University of Minnesota suggests that the global yields of most biofuel crops have often been exaggerated.

Matt Johnston and colleagues found that yields of most crops, including corn, rapeseed and wheat, have been overestimated by 100 to 150 percent or more. They discovered that current yield estimates were often based on data from the United States and Europe and didn't account for differences in climate, soils, technology and other factors that influence agricultural outputs in other nations especially in the developing world. For the study, the researchers drew on agricultural data from nearly 240 countries to calculate the potential yields of 10 biodiesel crops and 10 ethanol feedstocks worldwide.

For instance, Johnston noted that in Canada, one of the world's largest producers of rapeseed, the average yield of rapeseed biodiesel is just 550 liters per hectare. This is nearly half the estimates in yield tables, and well below the average for other developed nations.

Read the open-access article published by Environmental research Letters at http://dx.doi.or/10.1088/1748-9326/4/1/014004 The media release is available at http://www.news.wisc.edu/16127