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Move over sugarcane – here comes sweet sorghum

sorghum usda.jpgPosted for Jeff Tollefson

Following months of bad news on biofuels, a non-profit research institute is injecting a bit of optimism into the public debate by highlighting an old crop that can simultaneously provide both food and fuel: sweet sorghum (Reuters).

The timing couldn’t be better, given the ongoing global food crisis and the now ever-present worries about where our next gallon of fuel will come from. One report went so far as to suggest sweet sorghum might be the perfect bioenergy crop researchers have been looking for.

That might be going a little far, but sweet sorghum would appear to have some promising qualities, not the least of which is its ability to grow in dry climates. Mark Winslow an agronomist with the International Crops Research Institute for the Semi-Arid Tropics, more easily known as ICRISAT, went over some of the details this week with Nature.


The upshot is that sugars can be collected from the stalk, as with sugarcane, while grains are harvested separately. As usual, there’s a trade-off: you get a 25% reduction in grains as the plants pump more energy into stalks. But the theory is that the industrial interest in biofuels can be leveraged to increase overall yields in many areas, and thus provide additional food and biofuels despite the loss in grain productivity.

“There’s a potential to double, triple, quadruple yields in Africa,” Winslow said, simply because the yields there are so low compared to sorghum varieties grown in the United States.

It might make sense in the United States, too. Winslow says sweet sorghum performs on par with sugarcane in terms of the overall energy balance and thus could be a far more efficient option than corn ethanol, which, admittedly, isn’t very difficult.

To make all of this happen, farmers would need to switch from more common grain sorghum varieties to sweet sorghum, but Winslow says the transition is beginning in places like India. Industrial giant Tata Group has already partnered up with ICRISAT on a sweet sorghum ethanol plant there.

A pair of studies looking at the bioenergy potential of sweet sorghum are available here and here (subscription required).

Image: a researcher with sorghum flowers / USDA

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    Bob said:

    Quick, Subsidies, we need subsidies for sweet sorghum!

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