Death comes to us all. Life's but a walking shadow | I could only read the abstract and couldn't see the figures but if I understand his premise the gist of it is " Corn stover made into fuel is converted to carbon dioxide faster than if it is not harvested and allowed to degrade naturally." That's stating the obvious. I think it was the University of Minn. that did the long term study comparing residue degrading and soil carbon using no-till vs conventional plowing. The results suggests that under either system the vast majority of crop residue degrades to carbon dioxide within a very few years (1-3) Carbon sequestration is negligible under any typical agricultural cropping system. Significant carbon sequestration only occurs in forestry type situations where the biomass accumulates as woody tissue and even then is relatively modest. The important idea to remember is that by retaining and incorporating enough crop waste you can at the minimum maintain adequate soil organic matter which in turn maintains soil fertility. Too much crop residue can actually decrease productivity by trapping fertilizer nutrients.
His observation and premise simply overlooks the more important idea that biofuels don't add new carbon to the system but recycles what is present and in doing so traps solar energy as motor fuel which we can use.
If there is any argument against biofuels it may be that our conversion processes aren't efficient enough. The fundamental true of the matter is you can trap a tremendous amount of solar energy in the form of biomass with very modest energy costs using agricultural systems. For instance it is simple to show that the energy value of just the grain portion of a corn crop (4-5 ton) is far more than the 10-15 gallons of fuel equivalents it takes to make the nitrogen, grow and harvest the crop. The argument should not be with the overall cost benefit but the efficiency of the process.
I really dislike how some people make a false argument which is then used to discredit the whole program.
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Bad "science" - biofuel post below.
