Engineering360: "Materials innovations sparked from agricultural waste"

Just to be clear, corn stalks are not "collected" by a combine harvester. In the corn header, the stalks are pulled downward at high speed by counter-rotating "rollers" through a pair of gapped "stripper plates" where the ear of corn pops off and proceeds into the combine. Stalks rarely enter the inside of the combine, though small bits and pieces may do so if they fracture during the stripping off of the ears. The residue out the back end of a combine includes cob pieces, dust, a few corn leaves, husks, silks, pieces of tassel, and occasional stalk chunks. If one were to try and collect any quantity of stalks, it would be necessary to do some secondary processing of the standing and broken-down stalks, move them into windrows, then bale them. Cattle feeding operations do this routinely for bedding/fodder.

Author here- absolutely true! Poor wording on my part in the caption, I had to go back and figure out why I was talking about "collecting" corn stalks when I saw your comment.
As a kid, I watched these run around in the fields north and west of my house. They didn't do much to collect the chunks afterwards, so that would be an additional step to actually collect it for other purposes.
Good catch, and thanks for the comment!