40 percent of corn straw can be removed from fields without harm

In Canada, scientists at the Indian Head Research Farm in Saskatchewan, studying the impact of corn straw removal on soil nitrogen and soil organic carbon, found that "The results would support the recommendation that some straw could be removed from fields providing that the frequency of removal was less than 66% and that no more than 40% of the aboveground residues other than grain are removed. From a crop management perspective, proper nitrogen fertility combined with no-till would further reduce the possibility of net losses in SOC and SON."

The researchers studied the impact of soil removal over a 50 year period.

A recent study conducted by Iowa State University found that "removing corn cobs from fields for use in cellulosic ethanol production appears to have no substantial impact on soil nutrient content."