More research reaffirms the use of crop residue for cellulosic ethanol

A group of Canadian researchers published a paper in the Agronomy Journal seeking to quantify the amount of crop residue that can be used for ethanol production without adversely impacting soil quality. They conducted two studies:

1. The first evaluated three harvesting systems and their impact on straw removal with baling
2. The second measured straw removal after 50 yr on soil quality and wheat production using a fallow-spring wheat-spring wheat rotation (F-W-W) with three different treatments imposed

Their conclusion: Measurements of soil organic carbon and nitrogen showed no differences after 50 yr of straw removal, and spring wheat grain yields and grain protein concentration were also not affected based on the second study. The potential therefore exists to use crop residues for ethanol production or other industrial purposes without adversely affecting the long-term productivity of medium- to heavy-textured soils providing that 40% of the total above ground residues other than grain are removed and the frequency of removal is no more than 2 yr out of three.

These findings are similar to other studies we've seen, some of which have shown that as much as 50 percent of the stover can be removed without negatively impacting soil quality. As mentioned in the prior post, POET is working with Iowa State University to study the impact to the soil of using corn cobs for ethanol production and thus far research has shown that it has little to no impact. This is something we will continue to monitor closely and the Agronomy Journal provided an important contribution.