The maize grew on a more-than-usual carbon dense medium. It's interesting that it increased its carbon content, but perhaps not surprising. Nice to see it measured and proven.
Of course. There is nothing about biogas or biofuels that's more efficient. We've known this for at least 15 years and nothing in the space has changed.
Well, one thing changed: Peat is an ancient carbon sink, so draining the peat bog and using it as fertilizer is a great way to increase carbon yields.
If only we could somehow feed coal to corn..
In all seriousness though, as you point out, even in the best of cases, biofuel from corn is more carbon intensive than gasoline.
Supposedly, some processes (such as ethanol 85 from sugar cane) make environmental sense.
They can spin it how they like. consuming arable land to make expensive gasoline is just a bad excuse to avoid making better solutions viable. Nevermind that food insecurity and poverty in "third world" countries generates a large amount of CO2 from the burning of fossil fuels for lighting, heating uninsulated structures, etc. Grow food... to feed people.