Poet say removing cobs for fuel helps corn grow

NEW YORK (Reuters) - Removing cobs from fields may help corn plants grow better and provide a feedstock for next-generation cellulosic ethanol, said a fuel expert at private company Poet, the top U.S. maker of ethanol.

Farmers traditionally use equipment that spits corn cobs back onto the soil after removing kernels for feed or for making traditional ethanol.

There are "indications that removing corn cobs may be beneficial" for growing corn, Mark Stowers, a research vice president at South Dakota-based Poet, told reporters in a teleconference.

When cobs rot in place, he said, they may remove nitrogen from the soil. Decomposing cobs also may leach compounds into the soil that inhibit corn growth, he said.

Poet hopes to be making a bit of cellulosic ethanol from cobs this year at a plant in Scotland, South Dakota.

Cellulosic ethanol is usually made by harnessing tiny life forms to break down the tough, woody bits of crop waste and non-food crops like grasses and fast-growing trees into sugars that can be fermented into fuel.

Companies are racing to make commercial levels of the fuel because the U.S. government has mandated that 16 billion gallons per year of cellulosic to be blended into gasoline by 2022 in an attempt to wean the country off foreign oil.

In Brazil, where ethanol is made from sugar cane, companies are trying to make cellulosic from cane waste. Brazil is the world's top ethanol maker after the United States.

Poet's South Dakota plant will make 20,000 gallons per year of cellulosic. That's a tiny amount compared to the U.S. capacity to make 11 billion gallons per year of traditional ethanol from corn kernels.

By 2011, Poet hopes to make 31 million gallons per year of cellulosic fuel from cobs at its Project Liberty plant in Iowa, which will be added on the back of a traditional ethanol plant that makes the alternative motor fuel from corn kernels.

Poet's chief executive Jeff Broin has said the United States could make 5 billion gallons per year from cobs.

The company collected cobs from 4,000 acres of farmland last year and will collect from nearly 10,000 acres this year to study how to harvest, process and transport the waste.

Some environmentalists have worried that using crop waste to make fuel could harm the soil by removing nutrients and increasing erosion. Stowers said corn cobs represent just 6 percent of the above ground waste of the corn plant and about 3 percent of the plant's nutrients.

Bruce Dale, a professor at Michigan State University, said any erosion from Poet's corn cob use would be well under levels considered acceptable by the government.

Stowers said Poet was also looking at using a little bit more of corn stover, or waste from the crop, to make cellulosic without harming the soil.

(Reporting by Timothy Gardner; Editing by David Gregorio)