January 11, 2007

US corn farmers use corn stover to make ethanol
 

Ethanol boom has prompted US corn farmers to seek alternative fuel source.

Scientists have now been considering turning crop residues such as corn stover into ethanol. Although corn stover, a leftover material provides nutrients for the soil and prevents erosion, it also has the potential for a new use: making ethanol.

It could provide added income to farmers already supplying the ethanol industry, said Susan Andrews, an ecologist with the Federal Natural Resources Conservation Service.

However, considering residues performed many ecosystem services, their removal should not be taken lightly, Andrews said.

Researchers have now been trying to figure out what percentage could be removed without affecting yields.

More residues could be removed from no-till land than from conventional plow fields, and cooler wet climates could tolerate removal better than dry fields. Low residue crops such as soy decompose fast, so farmers using a corn-soybean rotation should only remove stover and leave behind soy plant residue, explained Andrews.

Gregg Carlson, a soil scientist, said farmers must consider stover's value both as a natural fertiliser and a feed source when determining its worth on the open market.

Energy crops, which include switchgrass, elephant grass and fast-growing trees such as aspen and willow, could produce higher tonnes per acre for the industry, said Bruce Jamerson, president of VeraSun Energy Corp, a Brookings-based ethanol producer adding those plants materials had more energy than residues.

Other potential alternative fuel sources include garbage and forestry resources such as chips, bark and sawdust.

Jamerson said biomass technology was still being developed but had the potential to revolutionise the ethanol and fuel industries.