As the article points out, differences exist between different crops:
Efforts to work out which crops are most environmentally friendly have, until now, focused only on the amount of greenhouse gases a fuel emits when it is burned. Scharlemann and Laurance highlighted a more comprehensive method, developed by Rainer Zah of the Empa Research Institute in Switzerland, that can take total environmental impacts - such as loss of forests and farmland and effects on biodiversity - into account.
In a study of 26 biofuels the Swiss method showed that 21 fuels reduced greenhouse-gas emissions by more than 30% compared with gasoline when burned. But almost half of the biofuels, a total of 12, had greater total environmental impacts than fossil fuels. These included economically-significant fuels such as US corn ethanol, Brazilian sugar cane ethanol and soy diesel, and Malaysian palm-oil diesel. Biofuels that fared best were those produced from waste products such as recycled cooking oil, as well as ethanol from grass or wood.
Given that many government initiatives are mandating a shift to biofuels, these impacts and risks should be cause to re-examine the rationale behind selecting one crop over another.