Re:Carbon neutral? (Score 3, Informative)

Actually, plants get carbon from the air, and they do it for "free" (solar energy by way of photosynthesis). It's nitrogen that's the issue. It takes energy (and quite a bit of it) to reduce atmospheric nitrogen to a form that plants can use for protein. Fertilizer supplies nitrogen. That's where the carbon "footprint" comes in, since industrial fertilizer production burns carbon (or some alternative energy, of course).