I can back up J-Allen's story. When I was in engineering school, our civil engineering students also had a concrete canoe contest. Either it's a common practice for civil engineering students, or J-Allen and I went to the same school (University of Illinois at Chicago).
I had read the DuPont article and I re-read it. I have four comments. I own some DuPont stock so I wish them well. I design concrete structures and I like what pozzolans do, so I'm happy to have more sources. They and you talk to farmers other than those I see either making silage from cornstalks or plowing it under - or both, which is the primary similarity - they don't leave much in the field. I don't see any having trouble getting rid of such "waste." I've never talked to any who had any such "waste," either. They will often plant a rye cover crop over the winter for erosion control and to have something green to turn under in the spring, so the corn from last year doesn't "interfere with corn planting." Maybe this is it: they rotate their crops every few years; from the comment that the stover can "house insects and diseases that damage corn plants" it sounds like the Iowa farmers just grow corn. I mentioned this to my 12th-grade daughter who had an immediate and strong reaction: "Anyone who takes AP Environmental Science knows that one wants to use any organic matter they have in their soil." She has that class this year.
j-allen, on first reading, your story about concrete canoes sounds like a cross between a Mafia movie and one about college students' jokes. OTOH, I know these things are real, because there's a cement ship on the beach south of the Santa Cruz harbor. According to the local history I've heard, this one was originally built as a supply ship in 1918, and then got towed over here to become an entertainment spot. Here's the history: http://www.santacruzsentinel.com/ci_17234906 and here's a better photo (scroill down a ways): http://www.beachcalifornia.com/cement-ship-seacliff-beach.html
Evidently this ash is much different from "just a filler", used to reduce density. Foam peanuts are a filler that reduces density but does not add strength. The ash somehow enters into the chemical structure, which is totally different.
You're right, Ann, that second generation of biofuels isn't getting the same coverage as the first generation. It's good to see this new industry is turning to non-food crops grown on non-food-ready soil.
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